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Hydrangea

Hydrangea is a genus of approximately 75 species of flowering plants in the family Hydrangeaceae, native to eastern Asia and the Americas.^[1] These deciduous shrubs or climbers typically feature opposite, simple leaves that are 4 to 8 inches long, with toothed or lobed margins, and produce terminal clusters of flowers in rounded or umbrella-shaped corymbs.^[2] The flowers, which bloom from spring to fall, are small and fertile or larger and sterile, appearing in shades of white, pink, blue, or purple, with colors in some species like H. macrophylla influenced by soil pH—acidic conditions (pH below 5.5) yielding blue hues and alkaline conditions (pH above 6.5) producing pink.^[2] The genus name derives from the Greek words hydor (water) and aggeion (vessel), alluding to the cup-shaped seed capsules.^[2] Notable species include the bigleaf hydrangea (H. macrophylla), native to East Asia and prized for its mophead or lacecap inflorescences; the panicle hydrangea (H. paniculata), from China and Japan, which grows as a shrub up to 15 feet tall with cone-shaped flower clusters; the smooth hydrangea (H. arborescens), native to eastern North America and forming rounded bushes 3 to 5 feet high; the oakleaf hydrangea (H. quercifolia), also North American, known for its lobed leaves resembling oak foliage and exfoliating bark; and the climbing hydrangea (H. anomala subsp. petiolaris), a vine reaching 30 to 40 feet that clings to structures with aerial rootlets.^[3] Hydrangeas generally prefer moist, well-drained soils and partial shade to full sun, depending on the species, and many provide multi-season interest through summer blooms, attractive fall foliage, and winter structure.^[3] However, parts of the plants contain cyanogenic glycosides, making them toxic to humans and animals if ingested, though with low severity.^[2]

Taxonomy

Etymology

The genus name Hydrangea derives from the Ancient Greek words húdōr (ὕδωρ), meaning "water," and angeîon (ἀγγεῖον), meaning "vessel" or "capsule," alluding to the plant's cup-shaped seed capsules that resemble water-holding containers.^[4] This etymological reference highlights a key morphological feature of the genus, where the dehisced capsules retain moisture, reflecting the plant's affinity for damp environments.^[4] The name was first formally established in scientific nomenclature by Carl Linnaeus in his 1753 work Species Plantarum, where he described the type species Hydrangea arborescens based on specimens from Virginia.^[5] Linnaeus's description marked the genus's introduction into binomial taxonomy, building on earlier observations of North American specimens introduced to European gardens in the early 18th century.^[6] An alternative historical association links the common name "Hortensia"—a Latinized form used particularly in French contexts—to Nicole-Reine Lepaute (1723–1788), a prominent French astronomer and mathematician known as Hortense, who contributed to comet discoveries and ephemeris calculations in the 18th century.^[7] This naming is attributed to the botanist Philibert Commerson, who encountered Asian hydrangeas during his voyages and reportedly coined "Hortensia" around 1771, possibly in her honor, though the precise inspiration remains a subject of botanical lore.^[8]

Classification

Hydrangea belongs to the family Hydrangeaceae in the order Cornales, which is situated within the core eudicots clade of angiosperms.^[9] The genus encompasses approximately 70–100 species of shrubs, small trees, and climbers, with the most recent assessments accepting 98 species.^[9] Within the family Hydrangeaceae, Hydrangea is placed in the subfamily Hydrangeoideae, specifically the tribe Hydrangeeae. Close relatives include genera such as Philadelphus (mock-orange) and Deutzia, which belong to the sister tribe Philadelpheae; these relationships were established through phylogenetic analyses using DNA sequences, including chloroplast and nuclear markers, conducted in the early 2000s.^[10] Recent taxonomic revisions have refined the classification of Hydrangea based on molecular phylogenetic data, leading to ongoing debates about its infrageneric divisions, such as recognition of subgenera like Hydrangea and others derived from sections like Cornidia. For instance, phylogenomic studies from 2024 propose an updated framework incorporating character evolution and expanded taxon sampling to resolve polyphyly in certain clades.^[11]^[12] As of 2025, complete genomic sequencing for the genus remains limited, with high-quality assemblies available only for select species like H. macrophylla, while ongoing research explores polyploidy in cultivated varieties to inform breeding and evolutionary insights.^[13]^[14]

Description

Morphology

Hydrangea plants display a range of growth forms, predominantly as deciduous shrubs that typically reach heights of up to 3 m, though certain species can develop into small trees or, in the case of evergreen climbers like H. seemannii, ascend to 10–12 m using aerial rootlets for attachment.^[15]^[16] These woody perennials often exhibit a rounded or upright habit, with some forming multi-stemmed structures from the base.^[17] The leaves of Hydrangea are arranged oppositely on the stems, simple in shape, and range from ovate to elliptic, with serrate or dentate margins and lengths of 4–20 cm; stipules are absent, and venation is typically pinnate or acrodromous.^[16] The stems are woody, featuring lenticels for gas exchange, and in some species such as climbing forms, the bark is exfoliating or peeling, adding textural interest.^[18] The root system is fibrous, frequently forming symbiotic associations with mycorrhizal fungi to enhance nutrient uptake.^[19]^[20] Inflorescences are borne terminally as corymbs or panicles, measuring 10–30 cm across, and comprise a mix of small, fertile flowers—each with 4 sepals, 4 petals connate at the base, and 8–10 stamens—and larger, showy sterile florets featuring 4 enlarged, petaloid sepals that attract pollinators.^[16]^[21] Following pollination, the ovary develops into a dry, dehiscent capsule containing numerous small seeds, which aids in wind dispersal.^[16]

Life Cycle

Hydrangea species are perennial shrubs or climbers, mostly deciduous but some evergreen, that complete their life cycle over multiple years, typically spanning 20 to 50 years in the wild depending on environmental conditions and species.^[22] The cycle begins with seed germination, which occurs in spring under moist, protected conditions, requiring light exposure and consistent humidity for the tiny dust-like seeds to sprout within about two weeks.^[23] Vegetative growth follows during summer, characterized by rapid leaf expansion and stem elongation, forming the rounded habit typical of most species, with dark green, serrated leaves emerging from overwintered buds.^[24] Flowering initiates in late spring to early summer, continuing through autumn (typically May to October in temperate zones), as inflorescences develop from buds formed the previous year on old wood in many wild species.^[25] These buds overwinter and break dormancy with warming temperatures, producing clusters of fertile and sterile florets in lacecap or mophead forms. Reproduction is primarily sexual, with fertile flowers pollinated by insects such as bees (Hymenoptera) and flies (Diptera), leading to the production of small, winged seeds dispersed by wind.^[26] Sterile florets enhance showiness to attract pollinators, while some species exhibit limited asexual reproduction through clonal propagation via rhizomes or suckers in natural settings.^[27] As autumn progresses, senescence occurs with leaf coloration and drop in deciduous species, transitioning the plant into winter dormancy where above-ground growth ceases and energy is conserved in roots and crowns.^[28] This dormant phase lasts through cold months, with buds protected against frost to ensure spring resurgence. Wild Hydrangea species generally flower once annually on old wood, though certain cultivars vary by reblooming on new growth produced in the current season.^[25]

Environmental Factors

Flower Colors and Soil pH

The flower colors of certain Hydrangea species, particularly the mophead and lacecap varieties of H. macrophylla, can range from blue and purple to pink and red, depending on soil conditions. In contrast, species such as H. paniculata typically produce white or green flowers that remain unaffected by soil pH variations.^[29]^[30] This color variation arises from the behavior of anthocyanin pigments, primarily derivatives of delphinidin such as delphinidin-3-glucoside, which are present in the sepals. In acidic soils with a pH below 5.5, aluminum ions (Al³⁺) become more available for uptake by the plant, forming stable blue-colored complexes with these anthocyanins. In alkaline soils with a pH above 6.5, aluminum availability decreases as it precipitates out of solution, allowing the anthocyanins to exhibit pink or red hues. At neutral pH levels between 5.5 and 6.5, a mixture of these forms results in purple coloration, reflecting an ionic equilibrium where metal complexation influences pigment stability and absorbance properties.^[31]^[32]^[33] Gardeners can adjust these colors practically by amending the soil: applying aluminum sulfate lowers pH and promotes blue flowers, while adding lime raises pH to encourage pink ones, with changes typically visible in 3 to 6 months as the plant absorbs the altered chemistry. The responsiveness to these adjustments varies by cultivar due to genetic differences; for instance, H. macrophylla 'Nikko Blue' readily turns blue in acidic conditions with sufficient aluminum.^[30]^[34]^[35] Recent research as of 2025 has explored the genetic underpinnings of this pH-dependent coloration, identifying key genes in anthocyanin biosynthesis pathways, such as HmWDR68, a WD40 transcription factor that regulates blue pigment formation in infertile flowers. Studies on gene expression profiles in H. macrophylla cultivars reveal how environmental pH influences regulatory networks linking aluminum uptake to delphinidin production, providing insights into selective breeding for stable colors.^[36]^[37]

Habitat and Distribution

Hydrangea species are primarily native to eastern and southeastern Asia, with the majority of the genus's 70–75 total species occurring there, with concentrations in China, Japan, Korea, the Himalayas, and extending to Indonesia. In the Americas, around 20 species are found, mainly in the southeastern United States, Mexico, Central America, and western South America. These distributions reflect the genus's origins in diverse temperate and subtropical regions, with the highest species diversity in Asian montane forests. Preferred habitats for Hydrangea include moist, shaded woodlands, stream banks, rocky slopes, and ravine edges, often in understory positions within forests. These plants thrive in subtropical to temperate climates, tolerating altitudes from sea level to over 3,000 meters, and favor well-drained, humus-rich soils with consistent moisture but partial shade to avoid desiccation. In the Americas, species like Hydrangea arborescens are commonly associated with mesic forests and floodplain edges, while Asian counterparts such as Hydrangea macrophylla occupy similar humid, low-light niches in evergreen broadleaf forests. Ecologically, Hydrangea species serve as key understory components in forest ecosystems, offering nectar and pollen resources for pollinators including bees and butterflies, and aiding in soil stabilization along waterways to prevent erosion. Some species demonstrate adaptations to local conditions, such as drought tolerance in drier Asian uplands through reduced transpiration, though the genus overall faces threats from climate change, with modeling studies predicting northward range shifts and habitat compression due to altered precipitation and temperature patterns in regions like China.

Diversity

Species

The genus Hydrangea comprises 98 accepted species, primarily shrubs or small trees, with a few vines and lianas, distributed across Asia, the Americas, and the Pacific.^[9] The greatest species diversity occurs in eastern Asia, notably in China, Japan, and Korea, where environmental conditions support a wide array of forms adapted to temperate forests and mountainous regions.^[9] For instance, Hydrangea involucrata, endemic to eastern Honshu in Japan, exemplifies regional endemism with its compact shrub form and lacecap inflorescences.^[38] Among the most prominent species is Hydrangea macrophylla, the bigleaf hydrangea native to southern Japan, renowned for its large, rounded mophead or flat lacecap flower clusters that can shift colors based on soil pH.^[39] In North America, Hydrangea arborescens, known as the smooth hydrangea, is a deciduous shrub with white, rounded blooms, widespread in the central and eastern United States.^[40] Hydrangea paniculata, the panicle hydrangea originating from central and southern China, Sakhalin, Japan, and Taiwan, features distinctive cone-shaped inflorescences that age from white to pink.^[41] Other notable North American species include Hydrangea quercifolia, the oakleaf hydrangea from the southeastern United States, characterized by its deeply lobed leaves resembling oak foliage and white pyramidal panicles.^[42] Hydrangea serrata, the mountain hydrangea from Korea and Japan, is often a smaller, dwarf shrub with serrated leaves and lacecap flowers, serving as a wild relative to cultivated bigleaf forms.^[43] The genus also exhibits diverse growth habits, such as the climbing vine Hydrangea anomala subsp. petiolaris, a self-clinging deciduous species native to Japan, Korea, and parts of China, with heart-shaped leaves and white lacecap blooms. In contrast, Hydrangea seemannii from northern Mexico to Central America is an evergreen liana with glossy leaves and creamy white flowers, highlighting the genus's adaptation to subtropical environments. No new Hydrangea species have been described since 2023, though taxonomic reclassifications continue, particularly within the H. aspera species complex in section Asperae, where historical mergers and splits of nominal taxa have refined classifications based on morphological and genetic evidence. A 2024 phylogenomic study proposed an updated infrageneric classification for Hydrangea sensu lato, recognizing five subgenera (including three newly elevated) and 19 sections, incorporating several satellite genera to resolve paraphyly.^[44]^[45]

Fossil Record

The fossil record of Hydrangea begins in the Paleogene, with the earliest confirmed evidence consisting of leaf impressions attributable to †Hydrangea alaskana from Oligocene (~34–23 million years ago, mya) shaly sandstones at Jaw Mountain on the Alaska Peninsula. These fossils, described from Tertiary strata, exhibit dentate margins and venation patterns closely resembling those of modern Hydrangea species, indicating the genus's presence in high-latitude, temperate to subtropical forests during a period of global warming post-Eocene.^[46] Fossil diversity increases from the Oligocene and Miocene (23–5 mya), with remains including fruits, seeds, and inflorescences documented from both Europe and North America; notable examples are the four †Hydrangea polonica seeds extracted from middle Miocene freshwater deposits in the Nowy Sącz Basin, Poland, and fruiting panicles from the Oligocene Bridge Creek flora in central Oregon. These Miocene specimens, often preserved as compressions or impressions, reveal morphological features such as capsular fruits and compound inflorescences akin to extant taxa. Pollen grains assigned to Hydrangea-like types have also been identified in Neogene sediments across Laurasia, collectively evidencing the genus's diversification within humid, broadleaf forests spanning the northern continents.^[47]^[48]^[49] Paleobotanical and phylogenetic data suggest Hydrangea originated through vicariance and dispersal across the Bering land bridge connecting Asia and North America during the late Paleogene to early Neogene, facilitating migration and subsequent radiation into western North American and eastern Asian habitats; limited evidence points to possible trans-Atlantic spread via the North Atlantic land bridge. The scarcity of macrofossils post-Miocene implies that by the Pliocene, Hydrangea distributions had stabilized, with modern patterns reflecting climatic cooling and habitat fragmentation.^[49] Although the macrofossil record provides a robust timeline, molecular clock studies as of 2025 remain constrained by sparse calibration points, estimating the stem divergence of Hydrangeeae (including Hydrangea) from other Cornales at approximately 48 million years ago in the middle Eocene (~40–50 mya range). This gap underscores the need for integrated fossil-genomic approaches to refine evolutionary timelines.^[49]

Cultivation

Growing Requirements

Hydrangeas thrive in partial shade, receiving 4 to 6 hours of direct sunlight daily, particularly morning sun followed by afternoon shade to prevent leaf scorch in warmer climates.^[50] In cooler regions, they can tolerate full sun provided the soil remains consistently moist, but excessive exposure in hot areas leads to wilting and reduced blooming.^[51] Well-drained, fertile soil that retains moisture without becoming waterlogged is essential for healthy growth, often enriched with organic matter like compost to improve structure and nutrient availability.^[52] Mulching around the base with organic materials helps conserve soil moisture and suppress weeds, while soil pH can be adjusted to influence flower color as discussed in the Flower Colors and Soil pH section.^[53] Consistent watering is crucial, with plants requiring about 1 inch of water per week, especially during dry periods or after establishment, as they are sensitive to drought stress that can cause bud drop and poor flowering.^[54] Once established, mature plants are somewhat more tolerant but still perform best with regular irrigation to maintain even soil moisture.^[55] Most hydrangea species are hardy in USDA zones 5 to 9, tolerating winter temperatures down to -20°F (-29°C) in protected sites, though young plants may need frost protection such as mulching or burlap wraps in colder zones.^[25] Pruning timing depends on whether the plant blooms on old wood (previous season's growth, prune after flowering) or new wood (current season's growth, prune in late winter), to avoid removing potential flower buds.^[56] Fertilization should use a balanced NPK formula, such as 10-10-10, applied in early spring at a rate of about 2 cups per 100 square feet, with additional light applications in May and July if growth is vigorous.^[55] Excess nitrogen should be avoided, as it promotes lush foliage at the expense of strong stems and blooms, potentially leading to leggy growth and increased disease susceptibility.^[28]

Propagation

Hydrangea plants are commonly propagated through asexual methods to maintain desirable traits in cultivars, as many hybrids produce sterile seeds. Softwood cuttings, taken from new growth in early summer, are a primary technique, particularly for species like Hydrangea macrophylla. These cuttings, typically 4-6 inches long, are treated with 1,000 ppm indole-3-butyric acid (IBA) and rooted in a moist peat-perlite medium under intermittent mist, achieving near 100% rooting success in 3-5 weeks.^[57] For H. arborescens and H. paniculata, similar protocols yield 100% rooting in 2-4 weeks, with cuttings overwintered for establishment.^[57] Hardwood cuttings offer a simpler alternative for hardy species, using dormant stems collected in late winter. These 6-8 inch cuttings, often from H. macrophylla or H. paniculata, are dipped in rooting hormone and planted directly outdoors in well-drained soil or pine bark substrate, rooting at 50-80% success by late spring.^[57] This method suits outdoor propagation without controlled environments, though it requires protection from extreme cold for optimal survival.^[58] Layering provides an effective in-situ method, especially for climbing or sprawling forms like H. anomala subsp. petiolaris. Ground layering involves bending a low branch into a shallow trench in early summer, wounding the stem and covering it with soil to encourage rooting while attached to the parent plant; roots typically form in 1-2 months before severing.^[59] Air layering, applied to upright stems, entails girdling a section, applying hormone, and wrapping with moist sphagnum moss in plastic; this is useful for non-climbers and achieves high success in humid conditions.^[60] Seed propagation is less common due to hybrid sterility in many cultivars, limiting it to species like H. quercifolia. Seeds are surface-sown in shallow trays in fall or spring without stratification, germinating in 2-8 weeks under cool, moist conditions at 60-70°F; however, germination can take months for other species and often results in variable offspring.^[57]^[61] Tissue culture, or micropropagation, has been used commercially since the 1980s to produce uniform, disease-free plants from meristem explants of cultivars. Shoots are initiated on Murashige-Skoog medium with cytokinins like benzyladenine, followed by rooting on auxin-enriched media; this method yields higher branching and quality compared to cuttings, particularly for H. quercifolia, and supports large-scale production.^[62]^[63]

Varieties and Cultivars

Hydrangea macrophylla, commonly known as bigleaf hydrangea, boasts thousands of registered cultivars, far exceeding those of other species in the genus, with selections primarily divided into mophead and lacecap types. Mophead cultivars feature large, rounded inflorescences composed mostly of showy, sterile florets, while lacecap varieties display flatter flower heads with fertile florets surrounded by a ring of sterile ones, offering a more delicate appearance. These cultivars have been bred extensively for enhanced color stability, particularly in achieving consistent blue or pink hues through aluminum uptake influenced by soil pH, as well as for reblooming capability on both old and new wood. A notable example is the 'Endless Summer' cultivar, introduced in the early 2000s, which produces mophead flowers in shades of blue or pink from late spring through fall, extending the bloom period significantly compared to traditional non-reblooming types.^[64]^[65]^[32]^[66] Breeding of Hydrangea cultivars originated in Europe during the 19th century, following the species' introduction from East Asia around 1789, with early selections focusing on ornamental flower forms and colors for garden use. By the late 1800s, nurseries in France, Belgium, and the United Kingdom had developed hundreds of H. macrophylla variants, emphasizing compact growth and vibrant inflorescences suitable for temperate climates. In the 2020s, modern breeding programs have prioritized disease resistance, particularly against powdery mildew, resulting in lines like the Cityline series of H. macrophylla, which exhibit strong tolerance while maintaining large, colorful blooms. These advancements build on interspecific hybridization techniques to incorporate traits from related species, improving overall vigor and reliability in cultivation.^[67]^[8]^[68]^[69] Among other species, H. paniculata cultivars like 'Limelight' are prized for their cone-shaped panicles that emerge lime-green and mature to pink or burgundy, providing seasonal color shifts on sturdy stems up to 8 feet tall. H. arborescens selections, such as 'Annabelle', produce massive white mophead flowers up to 12 inches across on compact plants reaching 4-5 feet, with improved stem strength in recent iterations for better display. Oakleaf hydrangea (H. quercifolia) hybrids and cultivars, including 'Snow Queen' and 'Alice', highlight the species' distinctive lobed foliage and exfoliating bark, with flowers transitioning from white to pink and exceptional resistance to leaf spot diseases. All Hydrangea cultivars adhere to the International Code of Nomenclature for Cultivated Plants, which governs naming conventions to ensure clarity and uniqueness in horticultural trade, distinguishing them from wild taxa.^[70]^[71]^[72]^[73]

Uses and Culture

Ornamental and Medicinal Uses

Hydrangeas are prized in ornamental gardening for their large, showy flower clusters and adaptability to various landscape features, including borders, hedges, and containers. Species such as Hydrangea paniculata and Hydrangea macrophylla thrive in these settings, providing structural definition and seasonal interest with blooms that often last from midsummer into fall.^[17]^[74] Their extended bloom period, sometimes spanning several months, enhances garden aesthetics, while the ability of certain varieties to shift flower colors based on soil pH adds dynamic visual appeal in cultivated settings.^[34] In landscaping, hydrangeas contribute to erosion control on slopes due to their dense root systems that stabilize soil, particularly in shaded or partially shaded areas where they naturally occur.^[75] They pair effectively with companion plants like ferns and hostas, which share preferences for moist, shaded conditions, creating layered textures and supporting biodiversity in woodland-style gardens.^[76] Medicinally, parts of hydrangea plants, particularly the roots and bark, have been utilized in traditional Chinese medicine, with Hydrangea paniculata employed to treat inflammation, fever, and kidney disorders, and research suggesting benefits for hypertension and renal protection.^[77]^[78] The plant contains bioactive compounds such as coumarins and flavonoids, which contribute to its purported anti-inflammatory properties, though clinical evidence remains limited.^[78] Despite these uses, hydrangeas pose toxicity risks due to cyanogenic glycosides present throughout the plant, which can release cyanide upon ingestion and cause symptoms including vomiting, diarrhea, lethargy, and in severe cases, respiratory distress or collapse.^[79] This toxicity affects pets like dogs and cats, as well as children, necessitating warnings to prevent accidental consumption; the plant is not recommended for internal use without proper processing under medical supervision.^[80]^[81] Industrially, hydrangea flowers serve as a source of natural dyes, yielding greens and blues when extracted and used in textile or artistic applications, leveraging their pigment content for eco-friendly colorants.^[82] Additionally, extracts from hydrangea leaves and flowers feature in some Asian cosmetics, particularly Korean formulations, where they provide moisturizing, soothing, and anti-aging benefits through antioxidant activity.^[83]^[84]

Cultural Significance

In Japan, hydrangeas, known as ajisai, hold a prominent place in cultural traditions, blooming during the late June rainy season and inspiring annual festivals such as those at temples like Meigetsu-in in Kamakura, where visitors admire thousands of blooms.^[85] These festivals celebrate the flower's association with gratitude and apology, stemming from a legend in which an emperor sent blue hydrangeas to his neglected consort's family as a gesture of remorse and appreciation for their understanding.^[86] Conversely, the plant's ability to change flower color based on soil pH has led to symbolism of fickleness or heartlessness, evoking impermanence in Japanese poetry and folklore.^[87] Native Asian species like Hydrangea macrophylla have been cultivated since the 8th century, with the earliest records appearing in the Man'yōshū anthology, highlighting their ornamental role in gardens and literature.^[88] In Western culture, particularly during the Victorian era, hydrangeas symbolized boastfulness and frigidity in the language of flowers, often gifted to convey arrogance due to their showy blooms that produce no fruit or coldness in relationships.^[89] This negative connotation arose from early 19th-century floriography texts, such as Henry Phillips' 1825 dictionary, which labeled the flower a "boaster" for its ostentatious display without substance, while sources like Robert Tyas' works equated it to "you are cold" or heartlessness.^[89] By the mid-19th century, however, hydrangeas gained popularity in European gardens for their lush foliage and versatility, adorning estates from England to France as symbols of abundance despite their earlier symbolic baggage.^[90] In Korea and China, hydrangeas feature in traditional practices emphasizing harmony and aesthetics, with species like Hydrangea serrata used to brew sugukcha tea, valued for its ornamental beauty in historical contexts.^[91] Chinese lore ties the flower to the Eight Immortals, portraying clusters of blooms as emblems of enlightenment and unity, with records of their cultivation in Ming Dynasty gardens like those in Suzhou.^[92] In both cultures, hydrangeas appear in bonsai forms and tea ceremony settings, where their rounded shapes enhance themes of balance, though they lack the centrality of more iconic plants like pine or camellia.^[93] In modern contexts, hydrangeas appear in literature and art without strong religious ties, evoking themes of memory and transience; for instance, Marcel Proust references them in In Search of Lost Time to symbolize fleeting beauty and emotional depth, drawing on their changeable hues.^[94] Japanese ukiyo-e prints from the Edo period further immortalize ajisai in serene landscapes, influencing contemporary floral art worldwide.^[93] In the 2020s, amid rising interest in sustainable gardening, hydrangeas symbolize adaptability and resilience, with drought-tolerant varieties promoted in eco-landscapes for their low-maintenance appeal and ability to thrive in varied soils, reflecting environmental harmony.^[95]

Pests and Diseases

Common Pests

Hydrangeas are susceptible to several insect and animal pests that can damage foliage, stems, flowers, and buds, though healthy plants often resist severe infestations.^[55] Common pests include sap-sucking insects like aphids, spider mites, and scale, as well as chewing pests such as Japanese beetles and browsing animals like deer and slugs.^[96] These pests thrive in stressed or poorly maintained plants but can be managed through monitoring and targeted interventions.^[97] Aphids, often green or black in color, are small soft-bodied insects that cluster on new growth and tender shoots of hydrangeas, sucking sap and causing leaves to curl, yellow, or distort.^[98] Their feeding also produces honeydew, a sticky excretion that promotes sooty mold growth on leaves.^[96] Control options include spraying with insecticidal soap or introducing natural predators like ladybugs.^[55] Spider mites, particularly the twospotted variety, are tiny arachnids that infest hydrangeas in hot, dry conditions, producing fine webbing on leaf undersides and causing stippling or bronzing of foliage.^[97] High populations can lead to leaf drop and reduced plant vigor.^[96] Management involves increasing humidity around plants, using miticides, or applying horticultural oils to disrupt mite life cycles.^[55] Scale insects, such as armored oystershell scale, appear as small, immobile bumps on stems and leaf veins, feeding on sap and weakening hydrangeas over time, often resulting in yellowing leaves or branch dieback.^[96] They are protected by waxy coverings that shield them from predators.^[99] Effective controls include wiping infested areas with alcohol swabs or treating with horticultural oils during the crawler stage.^[55] Other notable pests include slugs and snails, which chew irregular holes in hydrangea foliage, particularly in moist, shaded areas; deer, which browse on buds and young shoots, leaving jagged tears; and Japanese beetles, metallic green insects that skeletonize leaves and flowers during summer.^[100]^[101]^[96] Slugs and snails can be deterred with iron phosphate baits or cultural practices like reducing mulch; deer damage is best prevented with fencing or repellents; and Japanese beetles may be handpicked into soapy water or controlled with targeted insecticides.^[51]^[102]^[55] Prevention of pest issues in hydrangeas emphasizes integrated pest management (IPM) strategies, such as maintaining optimal growing conditions with proper watering, mulching, and pruning to promote plant health and resilience.^[97] Regular scouting for early signs of infestation allows for timely, non-chemical interventions like encouraging beneficial insects, alongside judicious use of approved treatments as needed.^[96]

Diseases

Hydrangeas are susceptible to several fungal, bacterial, and viral diseases that can compromise plant health, particularly in humid or poorly ventilated environments. Fungal pathogens are the most common, leading to leaf spots, wilts, and blights that reduce vigor and aesthetic appeal. Bacterial infections are less frequent but can cause similar symptoms under wet conditions, while viral diseases are rarer yet challenging to manage due to limited treatment options. Early detection and cultural practices, such as improving air circulation, are essential for mitigation. Powdery mildew, caused by the fungus Erysiphe polygoni, manifests as a white, powdery coating on the upper surfaces of leaves, often accompanied by yellowing or purplish blotches on the undersides.^[103] This disease thrives in shaded, humid areas with poor air movement, commonly affecting bigleaf hydrangea (Hydrangea macrophylla) in greenhouses or dense plantings.^[104] Treatment involves applying sulfur-based fungicides preventively in spring or early summer, with cultural controls like spacing plants for better airflow reducing incidence.^[103] Verticillium wilt, induced by soilborne fungi Verticillium dahliae or V. albo-atrum, leads to vascular discoloration, wilting of individual branches, and eventual dieback starting from the lower canopy.^[105] Hydrangeas, especially smooth hydrangea (H. arborescens), show yellowing leaves and stunted growth as the pathogen clogs water-conducting tissues, persisting in soil for years.^[106] No chemical cure exists; infected plants should be removed and destroyed to prevent spread, with resistant cultivars selected for replanting in affected areas.^[105] Anthracnose, primarily caused by Colletotrichum gloeosporioides, produces irregular brown leaf spots with dark margins that may coalesce into large blotches, along with sunken stem cankers in prolonged wet weather.^[107] This fungal disease favors cool, moist conditions and can defoliate plants severely if untreated, impacting H. macrophylla most.^[108] Management includes pruning infected parts and applying copper-based fungicides at bud break, combined with avoiding overhead watering to limit spore dispersal.^[107] Botrytis blight, or gray mold, results from Botrytis cinerea infection, appearing as water-soaked spots on leaves and flowers that develop fuzzy gray spores in high humidity.^[109] Flower buds often fail to open, turning brown and blighted, particularly during cool, wet periods when plants are overcrowded.^[110] Control focuses on cultural improvements like enhancing air circulation and removing debris, with fungicides used only if symptoms persist.^[109] Viral diseases in hydrangeas are infrequent but include hydrangea ringspot virus (HdRSV), which causes chlorotic ringspots, mosaic patterns, and leaf distortion on H. macrophylla.^[111] Transmission occurs mechanically via tools or sap, with no known vectors like insects.^[111] At least 17 viruses affect hydrangea as of 2024, emphasizing symptom management through rogueing infected plants and sanitation, as no curative treatments exist.^[111]

References

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Cultivate Hydrangeas - BYGL (osu.edu) - The Ohio State University
Jul 18, 2016 · Taxonomic Notes: The genus Hydrangea with its ~ 75 species of East Asian and American origins is in, ta dah – the Hydrangeaceae. Other familiar ...
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Hydrangea - North Carolina Extension Gardener Plant Toolbox
Hydrangeas are deciduous shrubs or climbers with flowers in terminal, round or umbrella-shaped clusters in colors of white, pink, or blue, or even purple. If ...
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Hydrangeas 101 | Chicago Botanic Garden
The genus Hydrangea includes flowering shrubs, small trees and climbers. Shrubs vary in size from dwarf specimens to enormous bushes. The two species native to ...
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Hydrangea - FNA - Flora of North America
Nov 5, 2020 · 1753. Craig C. Freeman. Common names: Graybeard sevenbark hortensia. Etymology: Greek hydor, water, and angeion, diminutive of angos, vessel or ...Missing: origin | Show results with:origin
[5]
Hydrangea arborescens in Flora of North America @ efloras.org
Hydrangea arborescens Linnaeus, Sp. Pl. 1: 397. 1753. [E]. Wild or smooth hydrangea Wild or smooth hydrangea. Hydrangea arborescens var. oblonga Torrey & A.Missing: Plantarum | Show results with:Plantarum
[6]
Hydrangea arborescens - Trees and Shrubs Online
H. arborescens is the type species of the genus, described scientifically by Linnaeus (1753). It was already in European gardens, introduced to Britain in 1736, ...
[7]
In a Word: An Anthology of Summer Blooms
Aug 5, 2021 · The hydrangea is also called the hortensia, a name honoring Nicole-Reine Hortense Lepaute, a French astronomer and mathematician. It's a ...
[8]
https://hortensien-garten.de/en/blogs/allgemeines/die-faszinierende-botanik-der-hortensien-ursprung-vielfalt-und-besonderheiten
[9]
Hydrangea Gronov. ex L. | Plants of the World Online | Kew Science
Accepted Species. Includes 98 Accepted Species. KB. Hydrangea acuminata Siebold & Zucc. Hydrangea albostellata Samain, Najarro & E.Martínez · Hydrangea ...
[10]
Hydrangeaceae - FNA - Flora of North America
Nov 5, 2020 · The two North American genera in the tribe, Decumaria and Hydrangea, are circumscribed here in their traditional senses. The Hydrangeaceae are ...
[11]
Molecular Phylogeny, Character Evolution, and Biogeography of ...
Jun 28, 2021 · In this study, we present a phylogenetic framework based on sequences from two low copy nuclear genes from a comprehensive taxon sampling of H. section ...
[12]
An updated infrageneric classification based on phylogenomics and ...
Mar 22, 2024 · In this study, we propose a comprehensive taxonomic reassessment of Hydrangea based on a reconstruction of its molecular phylog-eny based ...
[13]
insights into genomic recombination, gene transfer, and RNA editing ...
Aug 16, 2025 · Despite its importance for enhancing hydrangea varieties, no genomic resources have been published for this species to date. To bridge this ...
[14]
A Review of the Cytogenetic Studies in Hydrangea - ResearchGate
Aug 6, 2025 · A Review of the Cytogenetic Studies in Hydrangea. March 2025; Flower Research Journal 33(1):1-11. DOI:10.11623/frj.2025.33.1.01.
[15]
Hydrangea seemannii|Seemann's hydrangea/RHS Gardening
A woody, evergreen climber with aerial roots and leathery leaves up to 15cm long. Domed flower-heads, composed of greenish-white, fertile flowers surrounded by ...
[16]
Hydrangeaceae in Flora of North America @ efloras.org
Trichomes in most Hydrangeaceae consist of a long, unicellular portion, often borne on a multicellular base. The unicellular portion often bears tubercles on ...
[17]
Hydrangea paniculata (Panicle Hydrangea, Peegee Hydrangea)
Panicle hydrangea is a large, multi-stemmed, woody, deciduous shrub or small tree that is rapid-growing and coarsely textured.
[18]
Climbing Hydrangea - Bellarmine University
Besides its capability of growing in every plane and its feature of using aerial roots to climb trees or buildings its bark peels, which is unique among vines.
[19]
Best Tips for Healthy Bigleaf Hydrangea Roots - Greg
Oct 11, 2024 · Bigleaf hydrangeas boast a fibrous root system that plays a crucial role in their overall health. These roots are designed for efficient ...
[20]
Influence of endo-mycorrhiza on Hydrangea macrophylla subsp ...
Aug 5, 2025 · Mycorrhiza are symbiotic associations between plant roots and certain soil fungi which play a key role in nutrient cycling in the ecosystem ...
[21]
Hydrangea - Trees and Shrubs Online
Linnaeus (1753) first used the name for H. arborescens, the type species. It derives from the Greek hydor (water) and aggeion (vessel, container), presumably a ...
[22]
Smooth Hydrangea - The Ultimate Growing Guide - Proven Winners
The lifespan of smooth hydrangea can vary, depending on the variety and growing conditions. In general, individual plants will live for 20 to 50 years. Should I ...
[23]
Growing Hydrangeas From Seed - Gardening Know How
Jan 23, 2023 · Keep the soil moist and protect the seeds from cold and wind. They normally germinate in about 14 days. Gardening tips, videos, info and more ...
[24]
Hydrangea macrophylla (group) - Plant Finder
Hydrangea macrophylla, commonly called big leaf hydrangea, is a deciduous shrub with a rounded habit that, in the St. Louis area, typically grows 3-6' tall ...
[25]
FS1152: Hydrangeas in the Garden (Rutgers NJAES)
In cultivation, the plants generally grow to 3–5' tall, although in the wild, they can reach heights to upwards of 15'! Following several centuries of ...Missing: inflorescence | Show results with:inflorescence
[26]
Molecular Phylogeny, Character Evolution, and Biogeography of ...
Jun 29, 2021 · Background: Hydrangea section Cornidia consists of 26 currently accepted species and a yet undefined number of new species and erroneously ...
[27]
The Sterile Flowers of Hydrangea - In Defense of Plants
Jun 28, 2017 · These sterile flowers are technically colored up sepals. They don't produce reproductive structures or pollen. They are simply calling cards to insects that ...Missing: petals stamens
[28]
Hydrangea | Home and Garden Education Center
Hydrangea is a deciduous woody ornamental shrub or climbing plant that is known for its showy clusters of flowers that come in a large variety of colors.Missing: inflorescence | Show results with:inflorescence
[29]
Hydrangea blooms turn colors based on soil pH levels
Sep 20, 2012 · Soil pH indirectly changes flower color by affecting the availability of aluminum in the soil. When the soil is acidic (pH 5.5 or lower), ...Missing: macrophylla | Show results with:macrophylla
[30]
Hydrangea Care in South Carolina - HGIC@clemson.edu
Oct 31, 2025 · For blue flowers, maintain soil pH 5.0 to 5.5 (acidic) using sulfur or aluminum sulfate when new growth emerges in April. For pink flowers, ...
[31]
Insight into chemical mechanisms of sepal color development and ...
In this review, we summarize our recent studies on the chemical mechanisms underlying hydrangea sepal color development.
[32]
Curious Chemistry Guides Hydrangea Colors - American Scientist
The bloom colors are what really make the hydrangea stand out: They range from pink to blue, including all shades of lavender to violet to purple, as well as ...This Article From Issue · November-December 2014 · A Single PigmentMissing: HfDEL | Show results with:HfDEL
[33]
Identification of biochemical and molecular markers of blueability ...
The main anthocyanin form present in hydrangea sepals is delphinidin (up to 99 %, in Yuan et al. 2023) mainly in the form of delphinidin-3-glucoside (Del) ( ...
[34]
Hydrangeas For Mississippi Gardens
Smooth hydrangea is a shrub 5 to 6 feet high with weak twigs, slender leaf stems, and thin leaves. The leaves are 3 to 6 inches long and can be oval or heart- ...
[35]
Growing Tips: Hydrangeas, Color and Fertilizing - UMass Amherst
Too much lime can cause new growth to yellow due to lack of iron. To lower pH apply an acidic fertilizer such as aluminum sulfate, or wettable sulphur. Mulch ...
[36]
Regulation of blue infertile flower pigmentation by WD40 ... - PubMed
Feb 23, 2024 · This study investigates the WD40 transcription factor HmWDR68's role in developing the distinctive blue infertile flower colors in Hydrangea ...
[37]
Function of Anthocyanin and Chlorophyll Metabolic Pathways in the ...
Feb 28, 2025 · Hydrangea cultivars show varying colors even in the same soil, highlighting intricate gene regulatory mechanisms and the association between ...
[38]
Hydrangea involucrata Siebold | Plants of the World Online
Hydrangea involucrata Siebold ... The native range of this species is Japan (E. Honshu). It is a shrub and grows primarily in the temperate biome.
[39]
Hydrangea macrophylla (Thunb.) Ser. | Plants of the World Online
The native range of this species is S. Central Japan (to Izu Ōshima), Kazan Rettō. It is a shrub and grows primarily in the temperate biome.
[40]
Hydrangea arborescens L. | Plants of the World Online | Kew Science
Hydrangea arborescens L. ... The native range of this species is N. Central & E. U.S.A. It is a shrub or tree and grows primarily in the temperate biome.
[41]
Hydrangea paniculata Siebold | Plants of the World Online
Hydrangea paniculata is a shrub or tree native to Central & S. China, Sakhalin to Japan, and Taiwan, growing in the temperate biome.
[42]
Hydrangea quercifolia W.Bartram - Plants of the World Online
The native range of this species is SE. USA. It is a shrub and grows primarily in the temperate biome.
[43]
Hydrangea serrata (Thunb.) Ser. - Plants of the World Online
The native range of this species is Korea, Japan. It is a shrub and grows primarily in the temperate biome.
[44]
Hydrangea hullaballoo - Nursery Management
Aug 4, 2022 · Certainly, taxonomists do not agree on the number of species within Hydrangea. The “Flora of China” lists 73 species worldwide with 33 species ( ...Missing: 2023 | Show results with:2023<|separator|>
[45]
A New Fossil Species of Hydrangea - jstor
Locality: Jaw Mountain, Alaska Peninsula, 20 miles N.W. of. Aniakchak Bay. Formation: Tertiary shaly sandstone. Collector: W. R. Smith, U. S. Geological ...Missing: alaskensis | Show results with:alaskensis
[46]
[PDF] XVI (2)
Fossil localities of Hydrangea L. and Schefflera Forst, from the Tertiary of Poland: 1 Nowy Sącz, 2 Chyžne, 3. Ryc. 1. Stanowiska kopalne rodzajów Hydrangea.
[47]
[PDF] OREGON GEOLOGY - Cloudfront.net
It is rare at the Fossil locality and is also present but rare at Gray Ranch, Bridge Creek, and Dugout Gulch. A fruiting panicle of Hydrangea from Bridge Creek ...<|control11|><|separator|>
[48]
Phylogenomics and historical biogeography of Hydrangeeae ...
Jul 26, 2023 · The age estimate for the stem age of Hydrangeeae is 48.4 Ma (node 3; 95% HPD: 33.67–66.75 Ma), whereas the crown node age is estimated at 23.02 ...
[49]
Shrubby hydrangeas / RHS Gardening
Plant hydrangeas in sun or light shade in a spot sheltered from cold winds. Dislikes. Growing hydrangeas in very dry soil and full sun can lead to leaf scorch ...How to grow shrubby... · Hydrangea by colour · Hydrangea by plant size
[50]
General care for hydrangeas | OSU Extension Service
Hydrangeas like mostly shady spots, but some varieties can take more sun. The more sun your hydrangea gets, the more frequent watering that may be necessary ...Location, Planting And... · Soil · Color
[51]
Selecting Hydrangeas for the Home Landscape - Ohioline
Jul 20, 2018 · This fact sheet will help Ohio gardeners select hydrangeas based on the ability to attract pollinators, plant maintenance needs, and site requirements.Missing: subgenera Kirkianella
[52]
Hydrangea macrophylla (H)|hortensia/RHS Gardening
Cultivation. Grow in any moist but well-drained soil in partial shade or grow in sun if soil remains reliably moist. · Propagation. Propagate by softwood ...
[53]
Growing Hydrangeas : Landscape : Center for Agriculture, Food ...
Its large, lobed leaves resemble oak leaves and are up to 8" long and 5' wide. Oakleaf hydrangea grows with upright stems, reaching a height of 8'. It slowly ...Missing: inflorescence | Show results with:inflorescence
[54]
Hydrangea | Home & Garden Information Center - Clemson HGIC
Aug 15, 2024 · Hydrangeas, like bigleaf, have pink or blue flowers based on soil pH. They grow 4-12 feet tall, need well-drained soil, morning sun, afternoon ...Missing: inflorescence | Show results with:inflorescence
[55]
Hydrangea pruning / RHS Gardening
When to prune hydrangeas. Most pruning is carried out in late winter or early spring. However, climbing hydrangeas are pruned after flowering in summer.
[56]
[PDF] Hydrangea Production: Species-Specific Production Guide
The genus Hydrangea is expansive and includes approximately 1,000 species, hybrids and cultivars, which can be deciduous or evergreen shrubs, small trees or ...
[57]
Rooting Hydrangea Cuttings in Five Easy Steps - Illinois Extension
Sep 13, 2017 · Take 5-6" cutting, remove lower leaves, dip in hormone, insert in damp medium, water, cover, keep in shade, and expect roots in 2-3 weeks.Missing: hardwood | Show results with:hardwood
[58]
Get more hydrangea with these simple steps - MU Extension
May 16, 2023 · To layer, dig a trench and bend a limb section down into the trench. Remove a 1 inch small ring of the bark all the way around the limb. This is ...
[59]
Growing Bigleaf Hydrangea - CAES Field Report - UGA
Bigleaf hydrangeas need morning sun, afternoon shade, moist, well-drained soil. Prepare soil with compost, water when wilting, and avoid dry, exposed sites.
[60]
[PDF] Hydrangea Production - Tennessee State University
Pruning: Flowers on old wood so should be pruned after flowering. Propagation: By cuttings: Fairly easy to propagate using softwood cuttings and 5000 ppm IBA.<|separator|>
[61]
[PDF] Hydrangea Production: Cultivar Selection and General Practices to ...
Similarly, fresh H. quercifolia seeds, sown directly after collection, germinate at high percentages two weeks later. For detailed seed propagation informa-.
[62]
In vitro propagation of Hydrangea quercifolia Bartr. - ADS
In vitro propagation of Hydrangea quercifolia is possible through differentiation of leaf callus into plantlets and stimulation of axillary bud release from ...
[63]
Hydrangea Section Macrophyllae Cultivars I–J
The vast number of cultivars in this Section forces us to list them (still only a sample of the thousands which have been named) on a series of alphabetical ...
[64]
6 Types of Hydrangeas Demystified - Proven Winners
Learn about 6 types of hydrangeas including bigleaf, panicle, oakleaf & more. Discover key differences, bloom times, and hydrangea care tips for success.Missing: subgenera Kirkianella
[65]
Hydrangea - Breeding Insight
Traits that are most important to bigleaf hydrangea breeding are unique inflorescence architecture and flower color variation, floral induction (reblooming for ...<|separator|>
[66]
Hydrangeas | The Garden History Blog
Jul 27, 2024 · The final idea came from France where botanists had already determined that it was a new plant they had named Hortensia , the name that is still ...<|control11|><|separator|>
[67]
New Hydrangeas to Grow in the Garden - Horticulture
Feb 13, 2023 · The year 2023 sees several new hydrangeas coming to the retail market. Here's the rundown on some of these exciting shrubs.
[68]
[PDF] Hydrangea arborescens - Spring Meadow Nursery
Cityline® hydrangeas create irresistible one gallons, with large, vividly colored flowers, strong stems, dark glossy foliage, and excellent mildew resistance.
[69]
'Limelight' - Panicle Hydrangea - Proven Winners
In stock Rating 4.6 (107) 'Limelight' hydrangea has large, football-shaped flowers that change from green to pink/red/burgundy, blooms yearly, and is a time-tested classic.
[70]
Hydrangea arborescens 'Annabelle' (Smooth Hydrangea)
Beloved by gardeners, Annabelle Hydrangea is an exceptional flowering shrub with large flower clusters, up to 12 in. across (30 cm).
[71]
15 Varieties of Oakleaf Hydrangea - Epic Gardening
Jul 30, 2024 · Oakleaf hydrangeas are carefree growers with a naturalized aesthetic. Native to the southeastern US, they tolerate hot and humid summer conditions.
[72]
[PDF] International Code of Nomenclature for Cultivated Plants
German); Hydrangea macrophylla Groupe Hortensis (in French); Tulipa Grupo Darwin (in. Spanish); Rhododendron Jacqueline-Gruppen (in Swedish). Page 39. Art. 15 ...
[73]
[PDF] Hydrangea paniculata - Environmental Horticulture
Uses: container or above-ground planter; hedge; near a deck or patio ... Panicle Hydrangea can be used in a shrub border as a large sized accent ...
[74]
The many jobs hydrangeas can can fill in the garden
May 11, 2017 · Slopes can prove challenging because they are prone to erosion and they are not always the easiest terrain to maintain, but hydrangeas are an ...
[75]
Hydrangea Companion Plants: 20 Top Picks | Garden Design
Ferns are a great companion plant for hydrangeas, preferring the same growing conditions of partial shade and rich, moist soils. Japanese painted fern produces ...Missing: erosion control
[76]
Hydrangea paniculata coumarins attenuate experimental ... - NIH
Nov 22, 2023 · As a traditional Chinese medicine and a local food additive to improve flavor, Hydrangea paniculata has been used in southern China to treat ...<|separator|>
[77]
Hydrangea | ASPCA
Cyanogenic glycoside. Clinical Signs: Vomiting, depression, diarrhea. Cyanide intoxication is rare - usually produces more of a gastrointestinal disturbance.Missing: children | Show results with:children
[78]
Houseplants and Ornamentals Toxic to Animals - Toxicology
Clinical signs of toxicity include vomiting, diarrhea, almond-flavored breath, tachypnea, respiratory distress, hypotension, arrhythmias, sudden collapse, ...
[79]
Toxicology Answer: Take Care with the Bigleaf Hydrangea
Aug 9, 2022 · The most poisonous component is the cyanogenic glycoside amygdalin. There are other biologically active compounds found in the hydrangea species.Missing: credible | Show results with:credible<|separator|>
[80]
Create natural dyes with plant materials - Sweet Living Magazine
Hydrangea flowers – with added copper, a beautiful celery green. Broom stem – green. Calendula flowers – luminescent green. Camellia (pink, red petals) – green
[81]
Hydrangea Macrophylla Leaf Extract | Korean skincare
Hydrangea leaf extract moisturizes, soothes, protects skin, promotes cell regeneration, and improves skin tone and texture, also giving a natural glow.
[82]
Korean research links hydrangea extract to beauty-from-within ...
Mar 4, 2019 · “Our in vitro and in vivo experiments showed that [hydrangea extract] effectively prevents skin photoaging,” they wrote in their report, ...
[83]
Japanese Hydrangea (Ajisai) - Japan Guide
Dec 15, 2024 · Hydrangeas typically bloom during the rainy season in June and July, making them a symbol and the most popular flower of the season.
[84]
https://www.nutraingredients.com/Article/2019/03/04/Korean-research-links-hydrangea-extract-to-beauty-from-within-properties/
[85]
Why do blooming hydrangeas come in different colors? Japan ...
Jun 11, 2023 · Due to their color-changing characteristic, hydrangeas can symbolize fickleness in the "language of flowers," or floriography. The original ...Missing: heartlessness | Show results with:heartlessness
[86]
Historical changes of preference for planting of hydrangea in Japan
The oldest record of hydrangea in the country was described in Man'yōshū, a Japanese classic anthology written in the 8th century (Osawa & Arai 2016).
[87]
[PDF] Occasional Papers from the RHS Lindley Library
Dec 18, 2012 · This paper, from the RHS Lindley Library, focuses on the Victorian language of flowers, and is part of a series of occasional papers. The ...<|control11|><|separator|>
[88]
Hydrangea Meaning: Symbolism + History | Proflowers Blog
Aug 15, 2016 · The etymological meaning of hydrangea stems from the Greek words for water, hydros and jar, angos. It was given to the plant because of its ...
[89]
Hydrangea (Xiu Qiu, Chang Shan) | White Rabbit Institute of Healing
Hydrangea roots and rhizomes (Hydrangea arborescens) are used to treat urinary tract disorders, kidney toxicity and bladder infections and stones. The plant ...
[90]
The Chinese Myth behind Hydrangea (The Eight Immortals Flowers)
The cultivation of Hydrangea in China was very early, according to the record, it has been planted in the gardens of Suzhou in the Ming Dynasty. The Myth behind ...
[91]
Hydrangeas – 紫陽花 – ajisai – in Japanese art and elsewhere
Dec 18, 2011 · In Chinese art and culture – Joseph Needham quoted a 13th century text which described the chü-pa-hsien or 'assembly-of-the-eight-immortals- ...Missing: bonsai | Show results with:bonsai
[92]
The Two Hundred Sixty-Seven Plants in the Writings of Marcel ...
The two hundred sixty-seven plants in the writings of Marcel Proust, 18711922 : a documentary interpretation of the botanical influences on his literature.
[93]
Martha Stewart revives the art of floral landscaping for 2025
Jul 7, 2025 · Martha's lush garden features a variety of gorgeous hydrangeas, which elevate her outdoor space as well as provide a dynamic look to her greenhouse.
[94]
Hydrangea Diseases and Pests | Home and Garden Education Center
Other insects and pests that can sometimes cause damage to hydrangeas include oystershell scale (Lepidosaphes ulmi), and stem, leaf, and root-knot nematodes.
[95]
Hydrangeas - Alabama Cooperative Extension System -
Dec 10, 2018 · Hydrangeas, with their pink or blue cloud-shaped flowers and large, soft-green leaves, compose images of lazy summers in the shade.Missing: inflorescence | Show results with:inflorescence
[96]
Managing Pests in Gardens: Trees and Shrubs: Hydrangea—UC IPM
In some varieties, flower color can be affected by soil pH. Prune after bloom ... Aphids. Green peach aphid; Melon aphid. Armored scales. Oystershell scale.
[97]
Hydrangea: Identify and Manage Problems
Feb 6, 2024 · Cottony camellia scale is a sucking insect that feeds on the undersides of leaves. The feeding activity produces honeydew that grows sooty mold ...
[98]
Snails and Slugs / Home and Landscape / UC Statewide IPM ...
Look for silvery mucous trails to confirm that slugs or snails caused the damage, rather than other pests. ... hydrangea, California poppy, nasturtium, and ...
[99]
[PDF] Minimizing Deer Damage in Landscapes and Gardens
Strategies to minimize deer damage include repellents, fencing, scare devices, deer-resistant plants, and understanding deer behavior. Fencing is most ...
[100]
Ornamentals and Deer: Realities and Landscape Plant Options
Jan 31, 2023 · Deer damage can be managed by using repellents, fencing, and choosing plants with hairy, rough, or spiny textures, or aromatic compounds. ...
[101]
Hydrangea Diseases - Penn State Extension
Nov 21, 2023 · Botrytis Blight, Petals turn brown and fall. Leaf spots form, especially where faded petals have fallen. Flower buds are killed before opening.
[102]
Hydrangea: Powdery mildew | Hortsense
Jun 28, 2025 · Space plantings and prune to provide good air circulation. The cultivar 'Veitchii' is resistant to powdery mildew, while 'Nikko Blue' is ...Missing: Modern | Show results with:Modern
[103]
Verticillium Wilt of Trees and Shrubs - Wisconsin Horticulture
Mar 2, 2024 · Do not bury or compost these branches. Be sure to clean your pruning tools between cuts by treating them for at least 30 seconds in a 10% bleach ...
[104]
Verticillium Wilt: Identify, Prevent and Treat it - Gardenia.net
What are the Symptoms? · Wilting and Yellowing: Infected plants often show signs of wilting and yellowing of the leaves, particularly on one side of the plant.
[105]
Hydrangea: Fungal leaf spots - Hortsense
Jun 28, 2025 · Anthracnose may cause large, round or angular blotches which can appear all over the plant, including the flower heads. Both of these diseases ...
[106]
[PDF] HYDRANGEA | Disease and Insect Resistant Ornamental Plants
Anthracnose on hydrangea is caused by the fungus Colletotrichum gloeosporiodes and is prevalent on H. macrophylla (3). Symptoms first appear as brown spots ...<|separator|>
[107]
Hydrangea-Bud and Flower Blight
Hydrangea blight is caused by Botrytis cinerea fungus, needing 5-8 hours of wetness. Symptoms include water-soaked spots, reddish-brown blotches, and leaf ...
[108]
Botrytis Blight - Missouri Botanical Garden
Botrytis blight, or gray mold, is a fungal disease affecting buds, flowers, leaves, and bulbs, causing brown spots and gray mold. It spreads by wind or water.
[109]
[PDF] Viruses of Hydrangea | Purdue Landscape Report
Hydrangea mosaic virus (HdMV) none known; mechanical. Hydrangea latent virus (HdLV) none known; mechanical. ✔️. Hydrangea ringspot virus (HdRSV).