Hydrangeas (botanical name: Hydrangea ) are not only popular garden plants, but also botanically fascinating plants with a long history and worldwide distribution. In this article, we provide a comprehensive overview of the origin, biodiversity, and botanical characteristics of this fascinating plant family.
Systematics of hydrangeas
- Family: Saxifragaceae
- Genus: Hydrangea – Hydro = water, angeion = vessel – named after the striking vessel shape of the flower parts
- Species: Approx. 90 known species – shrubs, trees, lianas
Origin and distribution
The Hydrangea genus is native to several continents:
- Asia: Japan, China, Korea, Philippines, Java, East India, Himalayas
- America: North and South America
Important species and varieties
| Type | Origin | Special features |
|---|---|---|
|
Hydrangea macrophylla (garden/ball hydrangea) also called Hydrangea hortensia by Siebold in 1829 and Hydrangea hortensis by Smith in 1799. |
Japan | Most well-known species in Europe |
| Hydrangea macrophylla ssp. serrata (mountain hydrangea) | Japan | Smaller, finer leaves |
| Hydrangea arborescens (snowball hydrangea) | North America | White flower balls |
| Hydrangea quercifolia (oakleaf hydrangea) | North America | Oak leaf-like foliage |
| Hydrangea anomala ssp. petiolaris (Climbing Hydrangea) | Japan | Self-climbing species |
| Hydrangea paniculata (panicle hydrangea) | Japan | Panicle-like inflorescences |
| Hydrangea aspera ssp. sargentiana/aspera (velvet hydrangea) | Himalaya | Large, velvety leaves |
| Hydrangea heteromalla | Himalaya | Large white inflorescences |
| Hydrangea involucrata | Japan | Soft, felty leaves |
| Hydrangea stellata | Japan | Rare, star-shaped flower form |
Discovery and description
America:
The name Hydrangea was first used in Gronovius's Flora Virginica (1739). The Swedish naturalist Linnaeus described the same plant in his Species Plantarum (1753). Hydrangea quercifolia was described as a species in North America by Bartram (1791). Hippolito Ruiz Lopez and Antonio Pavon y Jimenez collected Hydrangea species in South America but gave them the genus name Cornidia (1798).
Asia:
Hydrangeas had been cultivated in Japan for many centuries, but contact with the outside world and foreigners was very difficult. The Japanese ruler Hideyoshi forbade priests from spreading them as early as 1587. It was not until 1775 that Carl Peter Thunberg, a student of Linnaeus, arrived on the artificial island of Deshima near Nagasaki, where he worked as a physician. He was the first to describe five Hydrangea species (1784). Siebold, who was in Japan from 1823 to 1829 and from 1859 to 1862, was the first to bring plants to Europe, including Hydrangea macrophylla "Otaksa" to Leiden. Siebold's description of four Asian species is still valid today. In 1860, the Russian botanist Carl Johan Maximowitz, commissioned by the Tsar, brought many hydrangeas to Saint Petersburg among his 400 living plants.
Europe:
In England there was an early interest in hydrangeas. In 1736 the first Hydrangea arborescens was introduced from America by Peter Collison. In 1790 Sir Joseph Banks brought a pink variety from China to Kew Garden near London. Within a few years it became known throughout Europe. In 1773 the French botanist Commerson brought the first plants to Paris. In Germany the first plants were planted in tubs in large parks and palaces in Saxony - for example in Pillnitz (from c. 1800 to c. 1980 probably Otaksa) and in Weesenstein. Three flowering hydrangeas ( Hydrangea macrophylla ) were shown at the flower exhibition in the Palais im Grosser Garten in Dresden on May 18, 1829. From 1830 onwards the botanist Nicole Charles Seringe assigned these hydrangeas the botanical name Hydrangea macrophylla .
Naming: Hydrangea / Hortensia
According to Jussieu, the botanist Commerson gave this name in 1771 in honor of a certain woman named Hortense. Three women may have been responsible for this:
- Hortense Barré: This young woman accompanied the botanist Peter Commerson, who had set out from France, on the Bougainville Expedition (1766–1769) to America. To avoid detection, she disguised herself as a young man. However, the fact that her first name was actually Jeanne calls this into question.
- Hortense Lepaute: A well-known astronomer, wife of a well-known watchmaker, and friend of Commerson. Several authors report that she is the most likely candidate for the naming. Unfortunately, her real first name was Nicole-Reine.
- Madame Hortense de Nassau: The daughter of the Prince of Nassau is the most likely name giver, as her father took part in the Bougainville expedition.
The idea that the plant was named after Hortense, the daughter of Empress Josephine, is rather unlikely. She was born a few years after the hydrangea was named.
Botanical characteristics of garden and mophead hydrangeas
(Hydrangea macrophylla)
- macrophylla [macro - gross-, phýllon - leaf]
- woody shrubs with fertile and sterile flowers
- However, the large and visible “flowers” are usually only sterile display flowers with striking petal-like, significantly enlarged calyxes.
- Flower buds are only formed when shoot growth is complete, shoots are mature and there is sufficient light intensity during the outdoor phase (June to October).
- Flowering occurs at high daily mean temperatures (> 18 °C) in August/
September/October delayed, blind shoots may occur.
Afterwards, the bud must mature and overwinter like other woody plants
(Dormant period). So never prune shoots in fall, winter, or spring; only remove the old flowers. The hydrangea only blooms on two-year-old wood. - Propagation of identical offspring can only occur vegetatively through cuttings. In breeding, however, the flowers of different plants are pollinated (cross-pollinated) and sown after maturity. The resulting offspring then often completely split, sharing some genetic traits. New forms and colors emerge. Hydrangea breeding has been practiced since around 1879 in approximately 40 companies in Belgium, Germany, England, France, the Netherlands, and Switzerland.
- Hydrangea macrophylla comes in 2 types.
Hydrangea types: Ball hydrangeas (rounded flower heads)
Lacecap types of marginal flower mophead hydrangeas
"Lace-up" [en. lace- lace, border] named by the famous collector and breeder Haworth-Booth (fertile flowers inside, they color only weakly and inconspicuously and sterile flowers outside at the edge of the inflorescence)
Famous Hydrangea Gardens & Collections
Some of Europe's most beautiful hydrangea gardens house impressive collections of up to 800 different species and varieties. Particularly worthwhile destinations for hydrangea lovers can be found in the following countries:
- Belgium
- Netherlands
- Great Britain
- Ireland
- France
- Germany
Conclusion: Hydrangeas are among the most fascinating ornamental plants in the world. Whether as a cultural symbol in Japan or a horticultural masterpiece in Europe, hydrangeas delight with their impressive variety, their changing color scheme, and their unique history.