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hydrangea

{{Short description|Genus of flowering plants}}

{{Redirect-several|Hydrangea|Hortensia}}

{{Automatic taxobox

|image=Hydrangea arborescens 139866012.jpg

|image_caption=Hydrangea arborescens in Catoctin Creek Park & Nature Center, Maryland, USA

|taxon=Hydrangea

|authority=Gronov. ex L.

|subdivision_ranks=Species

|subdivision=See text

|synonyms_ref={{cite web |url=https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:30010546-2 |title=Hydrangea Gronov. ex L. |website=Plants of the World Online |publisher=Board of Trustees of the Royal Botanic Gardens, Kew |date=2021 |access-date=17 September 2021 }}

|synonyms=

{{collapsible list|bullets = true

|title={{small|synonymy}}

|Adamia {{small|Wall.}}

|Broussaisia {{small|Gaudich.}}

|Calyptranthe {{small|(Maxim.) Nakai}}

|Cardiandra {{small|Siebold & Zucc.}}

|Cianitis {{small|Reinw.}}

|Cornidia {{small|Ruiz & Pav.}}

|Decumaria {{small|L.}}

|Deinanthe {{small|Maxim.}}

|Dichroa {{small|Lour.}}

|× Didrangea {{small|J.M.H.Shaw}}

|Forsythia {{small|Walter}}

|Heteromalla {{small|(Rehder) H.Ohba & S.Akiyama}}

|Hortensia {{small|Comm. ex Juss.}}

|Hydrangia {{small|L.}}

|Macnemaraea {{small|Willemet}}

|Pileostegia {{small|Hook.f. & Thomson}}

|Platycrater {{small|Siebold & Zucc.}}

|Sarcostyles {{small|C.Presl ex DC.}}

|Schizophragma {{small|Siebold & Zucc.}}

}}

|type_species = Hydrangea arborescens L.Hydrangea | International Plant Names Index. (n.d.). Retrieved January 5, 2024, from https://www.ipni.org/n/30010546-2

}}

Hydrangea ({{IPAc-en|h|aɪ|ˈ|d|r|eɪ|n|dʒ|ə}}{{Cite Cambridge Dictionaries|hydrangea|access-date=15 September 2024}}{{Cite Merriam-Webster|hydrangea|access-date=15 September 2024}} or {{IPAc-en|h|aɪ|ˈ|d|r|eɪ|n|dʒ|i|ə}}Sunset Western Garden Book, 1995: 606–607) is a genus of more than 70 species of flowering plants native to Asia and the Americas. Hydrangea is also used as the common name for the genus; some (particularly H. macrophylla) are also often called hortensia.{{cite web | title=Hydrangea macrophylla (H) | website=RHS | date=2025-02-04 | url=https://www.rhs.org.uk/plants/40792/hydrangea-macrophylla-(h)/details | access-date=2025-04-23}} The genus was first described from Virginia in North America,{{cite book | last=Linné | first=Carl von | last2=Salvius | first2=Lars | title=Caroli Linnaei ... Species plantarum :exhibentes plantas rite cognitas, ad genera relatas, cum differentiis specificis, nominibus trivialibus, synonymis selectis, locis natalibus, secundum systema sexuale digestas... | publisher=Impensis Laurentii Salvii | publication-place=Holmiae | year=1753 | doi=10.5962/bhl.title.669 | doi-access=free | url=https://www.biodiversitylibrary.org/itempdf/13829 | access-date=2025-04-23 | page=}} but by far the greatest species diversity is in eastern Asia, notably China, Korea, and Japan. Most are shrubs {{cvt|1-3|m}} tall, but some are small trees, and others lianas reaching up to {{cvt|30|m|ft|-1}} by climbing up trees. They can be either deciduous or evergreen, though the widely cultivated temperate species are all deciduous.{{cite web |title=The United States National Arboretum: Hydrangea FAQ |url=http://www.usna.usda.gov/Gardens/faqs/hydrangeafaq2.html |access-date=27 November 2008 |archive-url=https://web.archive.org/web/20130516083220/http://www.usna.usda.gov/Gardens/faqs/hydrangeafaq2.html |archive-date=16 May 2013 |url-status=dead}}

The flowers of many hydrangeas act as natural pH indicators, producing blue flowers when the soil is acidic and pink ones when the soil is alkaline.{{Cite web |date=2017-02-06 |title=Curious Chemistry Guides Hydrangea Colors |url=https://www.americanscientist.org/article/curious-chemistry-guides-hydrangea-colors |access-date=2024-05-27 |website=American Scientist |language=en}}

Etymology

Hydrangea is derived from Greek and means 'water vessel' (from {{lang|el|ὕδωρ}} húdōr "water" + {{lang|el|ἄγγος}} ángos or {{lang|el|ἀγγεῖον}} angeîon "vessel"),{{cite web|url=https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0057%3Aentry%3Du(%2Fdwr |title=ὕδωρ |last1=Liddell |first1=Henry George |last2=Scott |first2=Robert |work=A Greek-English Lexicon |publisher=Perseus Digital Library |date= 1940 }}{{cite web|url=https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0057:entry=a)/ggos |title=ἄγγος |last1=Liddell |first1=Henry George |last2=Scott |first2=Robert |work=A Greek-English Lexicon |publisher=Perseus Digital Library |date= 1940 }}{{cite web|url=https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0057:entry=a)ggei=on |title=αγγεῖον |last1=Liddell |first1=Henry George |last2=Scott |first2=Robert |work=A Greek-English Lexicon |publisher=Perseus Digital Library |date= 1940 }} in reference to the shape of its seed capsules.{{cite book|last=Gledhill |first= David |year= 2008 |title= The Names of Plants |publisher= Cambridge University Press |pages= 50, 206 |isbn=9780521866453}} The earlier name, Hortensia, is a Latinised version of the French given name Hortense, honoring the French astronomer and mathematician Nicole-Reine Hortense Lepaute.{{Cite web |url=https://en.oxforddictionaries.com/definition/hortensia |archive-url=https://web.archive.org/web/20171207135856/https://en.oxforddictionaries.com/definition/hortensia |url-status=dead |archive-date=December 7, 2017 |title=hortensia {{!}} Definition of hortensia in English by Oxford Dictionaries|website=Oxford Dictionaries {{!}} English |access-date=2017-12-07}} 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.{{cite journal |last1=Lynn |first1=W. T. |title=Madame Lepaute |journal=The Observatory |date=2 January 1911 |volume=34 |pages=77–78 |bibcode=1911Obs....34...87L |url=https://articles.adsabs.harvard.edu/full/1911Obs....34...87L |access-date=8 November 2022}}

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.

Colors and soil acidity

File:Hydrangea Flower Color Based on Soil pH.jpg

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.{{cite web |url=http://www.caes.uga.edu/Publications/pubDetail.cfm?pk_id=7829 |title=Publications - UGA Cooperative Extension |website=www.caes.uga.edu |access-date=31 May 2018}}{{cite web |url=http://www.usna.usda.gov/Gardens/faqs/hydrangeafaq2.html |title=USDA: Hydrangea Questions and Answers |access-date=31 May 2018 |archive-url=https://web.archive.org/web/20130516083220/http://www.usna.usda.gov/Gardens/faqs/hydrangeafaq2.html |archive-date=16 May 2013 |url-status=dead}} 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 aluminium ions and typically produce flowers that are blue to purple,{{Cite EB1911|wstitle=Hydrangea |volume=14 |page=34; see line five |quote=...but by the influence of sundry agents in the soil, such as alum or iron, they become changed to blue}}. 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.{{cite web |title=Hydrangea Plants |url=http://www.whiteflowerfarm.com/hydrangea-shrubs-spring.html}}

Species

File:Hydrangea paniculata - flower view 01.jpg]]

97 species are accepted.{{cite web |title=Hydrangea Gronov. ex L. |url=https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:30010546-2 |website=Plants of the World Online |publisher=Royal Botanic Gardens, Kew |access-date=25 April 2025}}

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Fossil record

File:Hydrangea knowltoni as Hydrangea bendirei USNM P36979 img3.jpg]]

{{extinct}}Hydrangea alaskana is a fossil species recovered from Paleogene strata at Jaw Mountain Alaska.{{cite journal |last=Hollick |first=Arthur |year=1925 |title=A New Fossil Species of Hydrangea |journal=Bulletin of the Torrey Botanical Club |volume=52 |issue=1 |pages=21–22 |doi=10.2307/2479996 |jstor=2479996}} †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.{{cite report |last1=Knowlton |first1=F.H. |year=1926 |chapter=Flora of the Latah Formation of Spokane, Washington, and Coeur d'Alene, Idaho |title=Shorter contributions to general geology, 1925 |series=Professional Paper |publisher=United States Geological Survey |volume=140 |pages=17–55, plates VIII-XXXI |doi=10.3133/pp140A |url=https://pubs.usgs.gov/pp/0140a/report.pdf}}{{cite book |last1=Chaney |first1=R. |last2=Axelrod |first2=D. |year=1959 |title=Miocene Floras of the Columbia Plateau: Part II. Systematic Considerations, by Ralph W. Chaney and Daniel I. Axelrod |publisher= Carnegie Institution of Washington |pages=1–226}}{{HathiTrust Catalog|uc1.c099384505|Miocene Floras of the Columbia Plateau}}

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.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.

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. 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:{{cite web |url=https://www.rhs.org.uk/plants/pdfs/agm-lists/agm-ornamentals.pdf |title=AGM Plants - Ornamental |date=July 2017 |page=96 |publisher=Royal Horticultural Society |access-date=6 November 2018}}

  • S. hydrangeoides var. concolor 'Moonlight'{{cite web |url=https://www.rhs.org.uk/Plants/110847/i-Schizophragma-hydrangeoides-i-var-i-concolor-i-Moonlight/Details |title=RHS Plantfinder - Schizophragma hydrangeoides var. concolor 'Moonlight' |access-date=6 November 2018}}
  • S. hydrangeoides var. hydrangeoides 'Roseum'{{cite web |title=RHS Plant Selector - Schizophragma hydrangeoides var. hydrangeoides 'Roseum' |url=http://apps.rhs.org.uk/plantselector/plant?plantid=1804 |access-date=3 June 2013}}
  • S. integrifolium{{cite web |title=RHS Plant Selector - Schizophragma integrifolium |url=https://www.rhs.org.uk/Plants/16816/Schizophragma-integrifolium/Details |access-date=5 March 2021}}

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.PDR for Herbal Medicine 3rd Edition Page 453 Hydrangeas are moderately toxic if eaten, with all parts of the plant containing cyanogenic glycosides.{{cite web |url=http://www.aspca.org/pet-care/poison-control/plants/hills-of-snow.html |title=Hills of Snow |access-date=31 May 2018}} Hydrangea paniculata is reportedly sometimes smoked as an intoxicant, despite the danger of illness and/or death due to the cyanide.{{cite web |url=http://www.erowid.org/herbs/hydrangea/hydrangea.shtml |title=Erowid Hydrangea Vault |website=www.erowid.org |access-date=31 May 2018}}{{cite news |url=https://www.theguardian.com/world/2014/feb/06/high-danger-hydrangea-french-police-hunt-gang |title=High danger hydrangea? French police hunt gang peddling 'cheaper weed' |first=Kim |last=Willsher |date=6 February 2014 |newspaper=the Guardian |access-date=31 May 2018}}

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.{{cite web |url=https://www.gardenista.com/posts/everything-need-know-hydrangeas/# |title=Everything You Need to Know About Hydrangeas |website=www.gardenista.com |access-date=15 June 2018 |date=2018-06-10}} Adding organic materials such as coffee grounds and citrus peel will increase acidity and turn hydrangea flowers blue.{{cite web |url=https://www.gardenista.com/posts/magic-trick-how-to-make-your-hydrangea-change-color/# |title=Hydrangeas: How To Change Color from Pink to Blue |website=www.gardenista.com |access-date=15 June 2018 |date=2016-05-10}}

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.{{cite web |url=http://www.goodhousekeeping.co.uk/lifestyle/gardening-advice/hydrangeas-chelsea-plant-of-the-year# |title=This plant has been named 'plant of the year' at the Chelsea Flower Show |access-date=31 May 2018 |date=2018-05-22}}

=In culture=

In Japan, ama-cha ({{lang|ja|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 ({{lang|ko|수국차}}) or isulcha ({{lang|ko|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!"{{cite web |url=http://www.rollmagazine.com/archive/oct11/articles/garden.php |title=Hydrangeas, Hydrangeas, Hydrangeas - Roll Gardening & Green :: Roll Magazine: Creative Living in the Hudson Valley |website=www.rollmagazine.com |access-date=31 May 2018}}

Hydrangea quercifolia was declared the official state wildflower of the U.S. state of Alabama in 1999.State Botanical SymbolsBy Alan McPherson, p.3

Hydrangeas were used by the Cherokee people of what is now the Southern U.S. as a mild diuretic and cathartic; it was considered a valuable remedy for stone and gravel in the bladder.{{cite book |last1=Hylton |first1=William H. |title=The Rodale herb book: how to use, grow, and buy nature's miracle plants |date=1974 |publisher=Rodale Press Book Division |location=Emmaus, Pa. |isbn=0-87857-076-4 |page=474 |oclc=610291480 |edition=Eighteenth Printing — September 1979 |url=https://www.worldcat.org/oclc/610291480 }}

Extrafloral nectaries were reported on hydrangea species by Zimmerman 1932, but Elias 1983 regards this as "doubtful".{{cite journal |date=2012-10-18 |first1=Marjorie G. |last1=Weber |first2=Kathleen H. |last2=Keeler |title=The phylogenetic distribution of extrafloral nectaries in plants |pages=1251–1261 |doi=10.1093/aob/mcs225 |journal=Annals of Botany |eissn=1095-8290 |volume=111 |issue=6|pmc=3662505 }}

Gallery

File:Hortensiapink.JPG|Hydrangea macrophylla

File:Hydrangea close up.jpg|Hydrangea flowers close up.

File:Pink Hydrangea Flowers.jpg|Flowers

File:Hydrangea-heads-pale.png|Hydrangea macrophylla, flowers

File:Blue Hydrangea.jpg|Hydrangea macrophylla, flowers

File:Hydrangea redoute.JPG|Hydrangea sp painted by the botanical artist Redouté.

File:Hydrangea quericifolia2.jpg|Hydrangea quercifolia

File:Hydrangea leaves.jpg|Hydrangea macrophylla, leaves

File:Wild hydrangea var annabelle.jpg|Wild Hydrangea v. Annabelle
Hydrangea arborescens

File:Hydrangea arborescens.jpg|Wild Hydrangea v. Annabelle
Hydrangea arborescens

File:Hydrangea arborescens annabelle.JPG|8" Annabelle Hydrangea Bloom. Hydrangea arborescens.

File:Hydrangea-aspera-zoo-cgn-07074-mutante.jpg|Hydrangea aspera ssp. sargentiana

File:BlueHydrangea.JPG

File:Hydrangea paniculata IMG 6629.JPG|Hydrangea paniculata

File:Hydranchia.JPG|Hydrangea flowers from Kerala, India

File:Hydrangeas corner.JPG|Hydrangeas in front of the Office de Tourisme Building in Chartres, France

File:Hydrangea-08-10-08.JPG|Hydrangea flowers at the "Cerro El Avila" National Park, Venezuela

File:Hydrangeea.jpg|Hydrangea flowers, Srinagar, Kashmir, India

File:Hydrangea flowers in the rain.jpg|Hydrangea flowers

File:Petrópolis - Cidade das Hortências e do Russo - Nevoeiro.jpg|Hydrangea flowers in Petrópolis, Brazil

File:Lagonegro3.jpg|Hydrangeas near the Black Lake of Gramado, southern Brazil

File:Hydrangea-flower.jpg|Purple hydrangea flowers

File:Hydrangea arborescens leaf.jpg|Hydrangea arborescens leaf

File:Hydrangea summer garden.jpg

File:Hydrangea flower white.jpg

File:Hydrangea flower summer garden.jpg

File:Wilted hydrangea.jpg

File:Hydrangea flower 3.jpg|Flower of hydrangea

File:Hydrangea flower 5.jpg|Flower of hydrangea

File:Vein sceleton hydrangea ies.jpg|Vein structure of a hydrangea leaf

File:Hydrangea arborescens (Smooth Hydrangea).jpg|Hydrangea arborescens (Smooth Hydrangea) in Calgary, Canada

Diseases

{{Main article|List of hydrangea diseases}}

References

{{EB1911|wstitle=Hydrangea |volume=14 |page=34}}

{{Reflist}}

External links

  • {{commons category-inline}}
  • [http://www.erowid.org/herbs/hydrangea/hydrangea.shtml erowid.org]
  • [http://www.efloras.org/florataxon.aspx?flora_id=110&taxon_id=115977 Flora of Nepal: Hydrangea species list]
  • [https://web.archive.org/web/20081209052446/http://www.urbanext.uiuc.edu/shrubselector/search_results.cfm?q=hydrangea Hydrangea – selecting shrubs]
  • [https://web.archive.org/web/20070927090002/http://www.botanik.de/mendel/image-galleries/blumen/hortensien Hydrangea species and hybrids]
  • [http://geekgardener.in/2010/08/07/propagating-hydrangea-from-cuttings/ Propagating Hydrangeas]
  • [https://web.archive.org/web/20161028153620/http://www.bgci.org/ourwork/Hydrangeas Red Listing of Threatened Hydrangeas]

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Category:Cornales genera

Category:Christmas plants

Category:Asterid genera