Geranium
| Geraniums | ||||||||||||
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 P. graveolens | ||||||||||||
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| Scientific classification | ||||||||||||
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| Species | ||||||||||||
| About 200: Pelargonium graveolens |
Pelargonium is a genus of flowering plants which includes about 200 species of perennial, succulent, and shrub plants, commonly known as geraniums. Confusingly, Geranium is the correct botanical name of the separate genus which contains the related Cranesbills. Both genera are in the Family Geraniaceae. Linnaeus originally included all the species in one genus, Geranium, but they were later separated into two genera by Charles L’Héritier in 1789. Gardeners sometimes refer to the members of Genus Pelargonium as "pelargoniums" in order to avoid the confusion, but the older common name "geranium" is still in regular use.
History and use
The first species of Pelargonium known to be cultivated was Pelargonium triste, a native of South Africa. It was probably brought to the botanical garden in Leiden before 1600 on ships which stopped at the Cape of Good Hope. In 1631, the English gardener, John Tradescant the elder, bought seeds from Rene Morin in Paris and introduced the plant to England. The name Pelargonium was introduced by Johannes Burman in 1738, from Greek πελαργός pelargos = "stork", because part of the flower looked like a stork's beak.
Other than grown for their beauty, species of Pelargonium such as P. graveolens are important in the perfume industry and are cultivated and distilled for its scent. Although scented Pelargonium exist which have smells of citrus, mint, or various fruits, the varieties with rose scents are most commercially important. Pelargonium distillates and absolutes, commonly known as "scented geranium oil" are sometimes used to supplement or adulterate expensive rose oils.
Pelargonium species are used as food plants by the larvae of some Lepidoptera species including Angle Shades.
Pelargoniums are believed to deter mosquitoes.
Garden geranium (Pelargonium x hortorum; syn. Pelargonium zonale) is one of the most common ornamental potted-plants, with over 200 varieties.
In 1988 the flower was described and illustrated in a comprehensive 3-volume work Pelargoniums of Southern Africa by Ellaphie Ward-Hilhorst with van der Walt and Vorster.
Cultivars
Species of Pelargonium are indigenous to Southern Africa and are drought and heat tolerant, and can tolerate only minor frosts. Pelargoniums are extremely popular garden plants, grown as annuals in temperate climates, and thousands of ornamental cultivars have been developed from about 20 of the species.
- Zonal varieties, also known as P. ×hortorum, are mainly derived from P. zonale and P. inquinans.
- Ivy-leaved varieties are mainly derived from P. peltatum.
- Regal varieties, also known as French geraniums or P. × domesticum are mainly derived from P. cucullatum and P. grandiflorum.
- Scented-leaf varieties are derived from a great number of species, amongst others P. graveolens.
Structural variations
Pelargonium leaves are usually alternate, and palmately lobed or pinnate, often on long stalks, and sometimes with light or dark patterns. The erect stems bear five-petaled flowers in umbel-like clusters called pseudoumbels. The shapes of the flowers have been bred to a variety ranging star-shaped to funnel-shaped, and colors include white, pink, red, orange-red, fuchsia to deep purple.
In early 2006 a long-awaited yellow-flowered variety was launched. Called the Guernsey Flair, it was supplied exclusively to the television shopping channel QVC in the UK, and all available plants were sold within a few minutes. See photo of yellow geranium. The flower has a much yellower hue than the cream-colored varieties which some developers had called yellow previously.
Horticultural pelargoniums (as opposed to botanical, the wild 'species') fall into six major groups, with zonals subdivided further:
- Angel
- Ivy-leaved = hanging
- Regal (or Royal) = French
- Shrubby-leaved
- Unique
- Zonal - erect and bushy
- Cactus-flowered
- Deacon (mostly dwarfs, cf. infra)
- Double-flowered
- Fancy-leaved
- Formosum hybrid
- Rosebud
- Tulip-flowered
- Single-flowered
- Stellar
- Straight Zonals
- It is also usual to classify small Zonals alternatively by size or odorous excellence :
- Dwarfs (small)
- Miniatures (even smaller)
- Parfum-leaved
Image gallery
P. graveolum
P. x domesticum
"Martha Washington"
native Pelargonium in South Africa Namaqualand
Pelargonium Stellar, a cultivar
Garden geranium (Pelargonium x hortorum)
Fair Ellen
References and external links
- Maria Lis-Balchin, ed., Geranium and Pelargonium: History of Nomenclature, Usage and Cultivation. (Taylor and Francis, 2002) ISBN 0-415-28487-2
- [1] - explanations in the on-line catalog of a Belgian breeder with over 1000 varieties of Pelargonium, most also illustrated, dozens added each year.
- [2] - The Pelargonium Page: descriptions of botanical species with plant and habitat photos