Hydrangea

Life-forms

Classification System: APG IV

Superregnum: Eukaryota
Regnum: Plantae
Cladus: Angiosperms
Cladus: Eudicots
Cladus: Core eudicots
Cladus: Asterids
Ordo: Cornales

Familia: Hydrangeaceae
Subfamilia: Hydrangeoideae
Tribus: Hydrangeeae
Genus: Hydrangea
Sectiones: H. sect. Asperae – H. sect. Broussaisia – H. sect. Calyptranthe – H. sect. Cardiandra – H. sect. Chinenses – H. sect. Cornidia – H. sect. Decumaria – H. sect. Deinanthe – H. sect. Dichroa – H. sect. Heteromallae – H. sect. Hirtae – H. sect. Hydrangea – H. sect. Macrophyllae – H. sect. Pileostegia – H. sect. Schizophragma – H. sect. Stylosae
Species: H. acuminata – H. albostellata – H. alternifolia – H. amamiohsimensis – H. ampla – H. anomala – H. arborescens – H. arguta – H. aspera – H. asterolasia – H. barbara – H. bifida – H. bretschneideri – H. caerulea – H. chinensis – H. chungii – H. cinerea – H. coenobialis – H. corylifolia – H. crassa – H. daimingshanensis – H. davidii – H. densifolia – H. diplostemona – H. fauriei – H. febrifuga – H. fistulosa – H. glaucescens – H. goudotii – H. gracilis – H. heteromalla – H. hirsuta – H. hirta – H. hydrangeoides – H. hypoglauca – H. integrifolia – H. involucrata – H. jelskii – H. kawagoeana – H. kwangsiensis – H. kwangtungensis – H. lingii – H. linkweiensis – H. liukiuensis – H. longifolia – H. longipes – H. luteovenosa – H. macrocarpa – H. macrophylla – H. mangshanensis – H. mathewsii – H. moellendorffii – H. mollissima – H. nebulicola – H. obtusifolia – H. ofeliae – H. paniculata – H. peruviana – H. petiolaris – H. platyarguta – H. preslii – H. quercifolia – H. radiata – H. robusta – H. sargentiana – H. scandens – H. schizomollis – H. seemannii – H. serrata – H. serratifolia – H. sikokiana – H. steyermarkii – H. strigosa – H. stylosa – H. taiwaniana – H. tarapotensis – H. tomentella – H. viburnoides – H. xanthoneura – H. yaoshanensis – H. zhewanensis
Nothospecies: H. × amagiana – H. × mizushimarum

H. aspera - - H. macrophylla - H. paniculata - - H. quercifolia

Source(s) of checklist:

Govaerts, R. et al. 2021. Hydrangea in Kew Science Plants of the World Online. The Board of Trustees of the Royal Botanic Gardens, Kew. Published online. Accessed: 2021 Oct 16. Reference page.

Paleospecies: †P. iljinskajae – †H. knowltonii
Name

Hydrangea Gronov. in L., Sp. Pl. 1: 397. (1753) [ emend. De Smet et al. (2015)]

Typus Hydrangea arborescens L.

Synonyms

Deinanthe Maxim., Mém. Acad. Imp. Sci. St. Petersb. ser. 7, 10: n. 16, 2 (1867)
Broussaisia Gaudich., Bot. Freyc. Voy. 479, t. 69 (1826)
Pileostegia Hook.fil. & Thomson, Journ. Linn. Soc. 2: 57, 76, t. 2 (1858)
Decumaria L., Sp. Pl. ed. 2, Append. 1663 (1763)
Forsythia Walter, Fl. Carol. 154 (1788) non Wahl (1805)
Cardiandra Siebold & Zucc., Fl. Jap. 119, t. 65, 66 (1839)
Dichroa Lour., Fl. Coch. 301 (1790)
Adamia Wall., Tent. Fl. Nep. 46. t. 36 (1824)
Cyanitis Reinw., Blume, Cat. Gew. Buiten. 68 (1823)
Cianitis Reinw.
Schizophragma Siebold & Zucc., Fl. Jap. 58, t. 26 (1835)
Hortensia Comm. ex Juss., Gen. 214 (1789)
Platycrater Siebold & Zucc., Fl. Jap. 1: 62, t. 27 (1835)
Cornidia Ruiz & Pav., Prod. 63. t. 35 (1794)
Calyptranthe (Maxim.) Nakai, Bull. Nat. Sci. Mus., Tokyo, No. 31, 52 (1952)
Calyptranthe (Maxim.) H.Ohba & S.Akiyama, J. Jap. Bot. 91(6): 349 (2016), comb. superfl.
Heteromalla (Rehder) H.Ohba & S.Akiyama, J. Jap. Bot. 91(6): 349 (2016)
Sarcostyles J.Presl ex DC., Prod. 4: 15 (1830)
× Didrangea J.M.H.Shaw
Macnemaraea Willemet
Hydrangia L.

Distribution
Native distribution areas:

Continental: Asia & America
Alabama, Argentina South, Arkansas, Assam, Bolivia, Borneo, Cambodia, Chile Central, Chile South, China North-Central, China South-Central, China Southeast, Colombia, Costa Rica, Delaware, District of Columbia, East Himalaya, Ecuador, El Salvador, Florida, Georgia, Guatemala, Hainan, Hawaii, Honduras, Illinois, India, Indiana, Inner Mongolia, Japan, Jawa, Kansas, Kazan-retto, Kentucky, Korea, Kuril Is., Laos, Lesser Sunda Is., Louisiana, Malaya, Maryland, Mexico Central, Mexico Gulf, Mexico Northeast, Mexico Northwest, Mexico Southeast, Mexico Southwest, Mississippi, Missouri, Myanmar, Nansei-shoto, Nepal, New Guinea, New Jersey, New York, Nicaragua, North Carolina, Ohio, Oklahoma, Panamá, Pennsylvania, Peru, Philippines, Qinghai, Sakhalin, South Carolina, Sulawesi, Taiwan, Tennessee, Thailand, Tibet, Venezuela, Vermont, Vietnam, Virginia, West Himalaya, West Virginia

References: Brummitt, R.K. 2001. TDWG – World Geographical Scheme for Recording Plant Distributions, 2nd Edition
References
Primary references

Linnaeus, C. 1753. Species Plantarum. Tomus I: 397. Reference page.

Additional references

De Smet, Y., Granados Mendoza, C., Wanke, S., Goetghebeur, P. & Samain, M.-S. 2015. Molecular phylogenetics and a new (infra)generic classification to alleviate polyphyly in tribe Hydrangeeae (Cornales: Hydrangeaceae). Taxon 64(4): 741–753. DOI: 10.12705/644.6 Open access PDF Reference page.
Manchester, S.R. (1994) "Fruits and seeds of the Middle Eocene Nut Beds Flora, Clarno Formation, Oregon." Palaeontographica Americana 58: 1–205.
Samain, M.S., Mendoza, C.G. & Salas, E.M.M. 2021. On Hydrangea peruviana, an endangered species from Ecuador, and Hydrangea oerstedii, very common in Costa Rica and Panama, and seven threatened Central and South American Hydrangeas, which have been confounded with these. PhytoKeys 171: 91-153. DOI: 10.3897/phytokeys.171.56351 Open access Reference page.

Links

Govaerts, R. et al. 2021. Hydrangea in Kew Science Plants of the World Online. The Board of Trustees of the Royal Botanic Gardens, Kew. Published online. Accessed: 2021 Oct 16. Reference page.
International Plant Names Index. 2021. Hydrangea. Published online. Accessed: Oct 16 2021. Reference page.
Tropicos.org 2021. Hydrangea. Missouri Botanical Garden. Published online. Accessed: 16 Oct 2021.
Hassler, M. 2021. Hydrangea. World Plants: Synonymic Checklists of the Vascular Plants of the World In: Roskovh, Y., Abucay, L., Orrell, T., Nicolson, D., Bailly, N., Kirk, P., Bourgoin, T., DeWalt, R.E., Decock, W., De Wever, A., Nieukerken, E. van, Zarucchi, J. & Penev, L., eds. 2021. Species 2000 & ITIS Catalogue of Life. Published online. Accessed: 2021 Oct 16. Reference page.

Vernacular names
dansk: Hortensia
Deutsch: Hortensien
Ελληνικά: Ορτανσία
English: Hortensia, Hydrangea
Esperanto: Hidrangeo
español: Hortensia
suomi: Hortensiat
français: Hortensia
magyar: Hortenzia
Bahasa Indonesia: Kembang bokor
italiano: Ortensie
日本語: アジサイ属
Lëtzebuergesch: Hortensen
lietuvių: Hortenzija
Nedersaksies: Attinsioa
Nederlands: Hortensia
norsk: Hortensia
polski: Hortensja
português: Hortênsia
русский: Гортензия
српски / srpski: Хортензија/Hortenzija
svenska: Hortensiasläktet
ไทย: ไฮเดรนเยีย
Tiếng Việt: Tú cầu
中文: 繡球花

Hydrangea (/haɪˈdreɪndʒə/[3][4] or /haɪˈdreɪndʒiə/[5]), commonly named the hortensia, is a genus of more than 70 species of flowering plants native to Asia and the Americas. By far the greatest species diversity is in eastern Asia, notably China, Korea, and Japan. Most are shrubs 1–3 m (3 ft 3 in – 9 ft 10 in) tall, but some are small trees, and others lianas reaching up to 30 m (100 ft) by climbing up trees. They can be either deciduous or evergreen, though the widely cultivated temperate species are all deciduous.[6]

The flowers of many hydrangea act as natural pH indicators, sporting blue flowers when the soil is acidic and pink ones when the soil is alkaline.[7]
Etymology

Hydrangea is derived from Greek and means ‘water vessel’ (from ὕδωρ húdōr "water" + ἄγγος ángos or ἀγγεῖον angeîon "vessel"),[8][9][10] in reference to the shape of its seed capsules.[11] The earlier name, Hortensia, is a Latinised version of the French given name Hortense, honoring French astronomer and mathematician Nicole-Reine Hortense Lepaute.[12] Philibert Commerson attempted to name the flower Lepautia or Peautia after Lepaute. However, the flower's accepted name later became Hortensia. This led to people believing Lepaute's name was Hortense, but the Larousse remarks that this is erroneous, and that the name probably came from hortus, garden.[13]
Life cycle

Hydrangea flowers are produced from early spring to late autumn; they grow in flowerheads (corymbs or panicles) most often at the ends of the stems. Typically the flowerheads contain two types of flowers: small non-showy fertile flowers in the center or interior of the flowerhead, and large, sterile showy flowers with large colorful sepals (tepals). These showy flowers are often extended in a ring, or to the exterior of the small flowers. Plants in wild populations typically have few to none of the showy flowers, while cultivated hydrangeas have been bred and selected to have more of the larger type flowers.

There are two flower arrangements in hydrangeas with corymb style inflorescences, which includes the commonly grown "bigleaf hydrangea"—Hydrangea macrophylla. Mophead flowers are large round flowerheads resembling pom-poms or, as the name implies, the head of a mop. In contrast, lacecap flowers bear round, flat flowerheads with a center core of subdued, small flowers surrounded by outer rings of larger flowers having showy sepals or tepals. The flowers of some rhododendrons and viburnums can appear, at first glance, similar to those of some hydrangeas.

Hydrangea flowers, when cut, dehydrate easily and wilt very quickly due to the large surface area of the petals. A wilted hydrangea may have its hydration restored by first having its stem immersed in boiling water; as the petals of the hydrangea can also absorb water, the petals may then be immersed, in room-temperature water, to restore the flower's hydration.[14][better source needed]
Colors and soil acidity
Hydrangea flower color changes based on the pH in soil. As the graph depicts, soil with a pH of 5.5 or lower will produce blue flowers, a pH of 6.5 or higher will produce pink hydrangeas, and soil in between 5.5 and 6.5 will have purple hydrangeas.

Hydrangea flower color can change based on the pH in soil. As the graph depicts, soil with a pH of 5.5 or lower will produce blue flowers, a pH of 6.5 or higher will produce pink hydrangeas, and soil in between 5.5 and 6.5 will have purple hydrangeas. White hydrangeas cannot be color-manipulated by soil pH because they do not produce pigment for color. In other words, while the hue of the inflorescence is variable dependent upon cultural factors, the color saturation is genetically predetermined. In most species, the flowers are white. In some, however, (notably H. macrophylla), they can be blue, red, or purple, with color saturation levels ranging from the palest of pinks, lavenders & powder blues, to deep, rich purples, reds, and royal blues. In these species, floral color change occurs due to the availability of aluminium ions, a variable which itself depends upon the soil pH.[15][16] For H. macrophylla and H. serrata cultivars, the flower color can be determined by the relative acidity of the soil: an acidic soil (pH below 7), will have available aluminum ions and typically produce flowers that are blue to purple,[17] whereas an alkaline soil (pH above 7) will tie up aluminium ions and result in pink or red flowers. This is caused by a color change of the flower pigments in the presence of aluminium ions which can be taken up into hyperaccumulating plants.[18]
Partial list of species
Hydrangea paniculata

Hydrangea anomala – (climbing hydrangea) Himalaya, southwest China
Hydrangea arborescens – (smooth hydrangea) eastern North America
Hydrangea aspera – China, Himalaya
Hydrangea bretschneideri – China
Hydrangea chinensis – China and Taiwan
Hydrangea chungii – China
Hydrangea cinerea – (ashy hydrangea) eastern United States
Hydrangea coenobialis – China
Hydrangea davidii – China
Hydrangea febrifuga – central & southern China to Malesia and New Guinea
Hydrangea glaucescens – China, Myanmar and Vietnam
Hydrangea gracilis – China
Hydrangea heteromalla – Himalaya, west and north China
Hydrangea hirta – Japan
Hydrangea hydrangeoides – Ulleungdo, Japan, Kurils
Hydrangea hypoglauca – China
Hydrangea integrifolia – China
Hydrangea involucrata – Japan, Taiwan
Hydrangea jelskii – Andes
Hydrangea kwangsiensis – China
Hydrangea kwangtungensis – China
Hydrangea lingii – China
Hydrangea linkweiensis – China
Hydrangea longifolia – China
Hydrangea longipes – western China
Hydrangea macrocarpa – China
Hydrangea macrophylla – (bigleaf hydrangea) southeast Japan, southern China
Hydrangea mangshanensis – China
Hydrangea paniculata – (panicled hydrangea) eastern China, Japan, Korea, Sakhalin
Hydrangea peruviana – Costa Rica and Panama, Andes
Hydrangea petiolaris – (climbing hydrangea) Japan, Korea, Sakhalin
Hydrangea quercifolia – (oakleaf hydrangea) southeast United States
Hydrangea radiata – (silverleaf hydrangea) southeast United States
Hydrangea robusta – China, Himalaya
Hydrangea sargentiana – western China
Hydrangea scandens – southern Japan south to the Philippines
Hydrangea serrata – Japan, Korea
Hydrangea serratifolia – Chile, western Argentina
Hydrangea strigosa – China
Hydrangea stylosa – China
Hydrangea tarapotensis – Andes
Hydrangea xanthoneura – China
Hydrangea zhewanensis – China

Fossil record
Hydrangea knowltoni

†Hydrangea alaskana is a fossil species recovered from Paleogene strata at Jaw Mountain Alaska.[19] †Hydrangea knowltoni has been described from leaves and flowers recovered from the Miocene Langhian Latah Formation of the inland Pacific Northwest United states. The related Miocene species †Hydrangea bendirei is known to from the Mascall Formation in Oregon, and †Hydrangea reticulata is documented from the Weaverville Formation in California.[20][21]

Four fossil seeds of †Hydrangea polonica have been extracted from borehole samples of the Middle Miocene fresh water deposits in Nowy Sacz Basin, West Carpathians, Poland.[22]
Cultivation and uses

Hydrangeas are popular ornamental plants, grown for their large flowerheads, with Hydrangea macrophylla being by far the most widely grown. It has over 600 named cultivars, many selected to have only large sterile flowers in the flowerheads. Hydrangea macrophylla, also known as bigleaf hydrangea, can be broken up into two main categories; mophead hydrangea and lacecap hydrangea.[23] Some are best pruned on an annual basis when the new leaf buds begin to appear. If not pruned regularly, the bush will become very "leggy", growing upwards until the weight of the stems is greater than their strength, at which point the stems will sag down to the ground and possibly break. Other species only flower on "old wood". Thus, new wood resulting from pruning will not produce flowers until the following season.

The following cultivars and species have gained the Royal Horticultural Society's Award of Garden Merit under the synonym Schizophragma:[24]

S. hydrangeoides var. concolor 'Moonlight'[25]
S. hydrangeoides var. hydrangeoides 'Roseum'[26]
S. integrifolium[27]

Hydrangea root and rhizome are indicated for the treatment of conditions of the urinary tract in the Physicians' Desk Reference for Herbal Medicine and may have diuretic properties.[28] Hydrangeas are moderately toxic if eaten, with all parts of the plant containing cyanogenic glycosides.[29] Hydrangea paniculata is reportedly sometimes smoked as an intoxicant, despite the danger of illness and/or death due to the cyanide.[30][31]

The flowers on a hydrangea shrub can change from blue to pink or from pink to blue from one season to the next depending on the acidity level of the soil.[32] Adding organic materials such as coffee grounds and citrus peel will increase acidity and turn hydrangea flowers blue.[33] A popular pink hydrangea called Vanilla Strawberry has been named "Top Plant" by the American Nursery and Landscape Association.

A hybrid "Runaway Bride Snow White", from Japan, won Plant of the Year at the 2018 RHS Chelsea Flower Show.[34]
In culture

In Japan, ama-cha (甘茶), meaning sweet tea, is another herbal tea made from Hydrangea serrata, whose leaves contain a substance that develops a sweet taste (phyllodulcin). For the fullest taste, fresh leaves are crumpled, steamed, and dried, yielding dark brown tea leaves. Ama-cha is mainly used for kan-butsu-e (the Buddha bathing ceremony) on April 8 every year—the day thought to be Buddha's birthday in Japan. During the ceremony, ama-cha is poured over a statue of Buddha and served to people in attendance. A legend has it that on the day Buddha was born, nine dragons poured Amrita over him; ama-cha is substituted for Amrita in Japan.

In Korean tea, Hydrangea serrata is used for an herbal tea called sugukcha (수국차) or isulcha (이슬차).

The pink hydrangea has risen in popularity all over the world, especially in Asia. The given meaning of pink hydrangeas is popularly tied to the phrase "you are the beat of my heart," as described by the celebrated Korean florist Tan Jun Yong, who was quoted saying, "The light delicate blush of the petals reminds me of a beating heart, while the size could only match the heart of the sender!"[35]

Hydrangea quercifolia was declared the official state wildflower of the U.S. state of Alabama in 1999.[36]

Hydrangeas were used by the Cherokee people of what is now the Southern U.S. A mild diuretic and cathartic, it was considered a valuable remedy for stone and gravel in the bladder.[37]

Gallery

Hydrangea macrophylla
Hydrangea macrophylla
Hydrangea flowers close up.
Hydrangea flowers close up.
Flowers
Flowers
Hydrangea macrophylla, flowers
Hydrangea macrophylla, flowers
Hydrangea macrophylla, flowers
Hydrangea macrophylla, flowers
Hydrangea sp painted by the botanical artist Redouté.
Hydrangea sp painted by the botanical artist Redouté.
Hydrangea quercifolia
Hydrangea quercifolia
Hydrangea macrophylla, leaves
Hydrangea macrophylla, leaves
Wild Hydrangea v. Annabelle Hydrangea arborescens
Wild Hydrangea v. Annabelle
Hydrangea arborescens
Wild Hydrangea v. Annabelle Hydrangea arborescens
Wild Hydrangea v. Annabelle
Hydrangea arborescens
8" Annabelle Hydrangea Bloom. Hydrangea arborescens.
8" Annabelle Hydrangea Bloom. Hydrangea arborescens.
Hydrangea aspera ssp. sargentiana
Hydrangea aspera ssp. sargentiana
Hydrangea paniculata
Hydrangea paniculata
Hydrangea flowers from Kerala, India
Hydrangea flowers from Kerala, India
Hydrangeas in front of the Office de Tourisme Building in Chartres, France
Hydrangeas in front of the Office de Tourisme Building in Chartres, France
Hydrangea flowers at the "Cerro El Avila" National Park, Venezuela
Hydrangea flowers at the "Cerro El Avila" National Park, Venezuela
Hydrangea flowers, Srinagar, Kashmir, India
Hydrangea flowers, Srinagar, Kashmir, India
Hydrangea flowers
Hydrangea flowers
Hydrangea flowers in Petrópolis, Brazil
Hydrangea flowers in Petrópolis, Brazil
Hydrangeas near the Black Lake of Gramado, southern Brazil
Hydrangeas near the Black Lake of Gramado, southern Brazil
Purple hydrangea flowers
Purple hydrangea flowers
Hydrangea arborescens leaf
Hydrangea arborescens leaf
Flower of hydrangea
Flower of hydrangea
Flower of hydrangea
Flower of hydrangea
Vein structure of a hydrangea leaf
Vein structure of a hydrangea leaf
Hydrangea arborescens (Smooth Hydrangea) in Calgary, Canada
Hydrangea arborescens (Smooth Hydrangea) in Calgary, Canada

Diseases
Main article: List of hydrangea diseases
References

This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). "Hydrangea". Encyclopædia Britannica. Vol. 14 (11th ed.). Cambridge University Press. p. 34.

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Łańcucka-Środoniowa M.: Macroscopic plant remains from the freshwater Miocene of the Nowy Sącz Basin (West Carpathians, Poland) [Szczątki makroskopowe roślin z miocenu słodkowodnego Kotliny Sądeckiej (Karpaty Zachodnie, Polska)]. Acta Palaeobotanica 1979 20 (1): 3-117.
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"RHS Plant Selector - Schizophragma hydrangeoides var. hydrangeoides 'Roseum'". Retrieved 3 June 2013.
"RHS Plant Selector - Schizophragma integrifolium". Retrieved 5 March 2021.
PDR for Herbal Medicine 3rd Edition Page 453
"Hills of Snow". Retrieved 31 May 2018.
"Erowid Hydrangea Vault". www.erowid.org. Retrieved 31 May 2018.
Willsher, Kim (6 February 2014). "High danger hydrangea? French police hunt gang peddling 'cheaper weed'". the Guardian. Retrieved 31 May 2018.
"Everything You Need to Know About Hydrangeas". www.gardenista.com. 2018-06-10. Retrieved 15 June 2018.
"Hydrangeas: How To Change Color from Pink to Blue". www.gardenista.com. 2016-05-10. Retrieved 15 June 2018.
"This plant has been named 'plant of the year' at the Chelsea Flower Show". 2018-05-22. Retrieved 31 May 2018.
"Hydrangeas, Hydrangeas, Hydrangeas - Roll Gardening & Green :: Roll Magazine: Creative Living in the Hudson Valley". www.rollmagazine.com. Retrieved 31 May 2018.
State Botanical SymbolsBy Alan McPherson, p.3
Hylton, William H. (1974). The Rodale herb book: how to use, grow, and buy nature's miracle plants (Eighteenth Printing — September 1979 ed.). Emmaus, Pa.: Rodale Press Book Division. p. 474. ISBN 0-87857-076-4. OCLC 610291480.