Pelargonium × hortorum

Appearance

They are stocky and large. The flowers can be single or double, and have five petals positioned regularly around the center. The leaves are often fragrant. The flowers come in many colours, including red, shades of pink, scarlet and white. Recently, orange and yellow cultivars have been developed. The inflorescence is carried by a long rigid peduncle, starting from the armpit of the upper leaves, so that the flowered head stands out clearly above the foliage.

Many cultivars have been grown since the late eighteenth century. Cultivars with very double flowers and no anthers are called Rosebud Pelargoniums since the flowers never open completely and therefore resemble a rose. Leaves of circular shape and have a winged venation and a leaf margin. The blade is covered by a dark annular area, more or less visible depending on the variety. The zoned geraniums are very floriferous plants, not quite demanding when it comes to water. Flowering occurs without interruption from spring until the last days of autumn.

Naming

The specific epithet "hortorum" is a genitive form of the Latin ""hortus"" and therefore corresponds to "horticultural". The name was created by the American botanist Liberty Hyde Bailey who in 1914, writes "The large number of forms of the common geranium, derives from the variation and probably the crossing of "P. zonale" and "P. inquinans" during more than a century of careful selections".

It is important to distinguish the botanical Latin term ""Geranium"", the extent of which has varied according to botanical knowledge over the centuries and the vernacular name of the French language ""geranium"" whose extension is defined by several centuries of use by amateur and professional gardeners.

Furthermore, most plants commonly called geraniums by florists and gardeners do not belong to the genus "Geranium" but to the genus "Pelargonium". Currently, most gardeners, amateur or professional, know perfectly well that the geraniums that decorate the balconies are "Pelargonium" but they are reluctant to use the term they find too pedantic. The term is not felt to be fully part of the common language and still remains marked as scholarly.

Evolution

The ancestors of Pelargonium zonal group are two species of wild pelargoniums of South Africa called "Geranium africanum". In the following century, Carl Linnaeus gave them a binomial name, Geranium zonal and Geranium inquinans, then the heir reclassified them in the genus Pelargonium. But this name will only be widely accepted in the 19th century, and in the meantime varieties and horticultural hybrids of these species were a great success with gardeners, they kept the habit they had taken to call them "geraniums", a term that was unambiguously in context.

The first ancestor of the zonal group, now known as Pelargonium zonal, was collected in the province of Western Cape in 1689 and was sent to Europe and described by the Dutch botanist 9 Jan Commelijn. Traces of its cultivation are then found in the gardens of the Duchess of Beaufort in England, an aristocrat passionate about exotic flowers that employed many gardeners to grow seeds brought back by sailors from abroad. In 1699 she produced a catalog of her collection of plants which she had the following year illustrated by artists. Among the paintings are what is now called Pelargonium zonal whose precise identification was made by the botanist John Ray.

It was only during the second half of the 18th century that the foundations of hybridization and floral biology began to be established through the work of two remarkable German experimenter Kurt Polycarp Joachim Sprengel. With the first, the technique of obtaining first and second generation hybrids is described for the first time. In 1793, Sprengel established that most hermaphroditic flowers could not be fertilized by their own pollen because their reproductive organs did not reach maturity at the same time. And we had to wait for the precise observations of the Italian microscopist Giovanni Battista Amici in 1830, to establish that the pollen germs by emitting a pollen tube that progresses to the egg.

The first traces of the culture of the second ancestor of the zonal group, now known as Pelargonium inquinans, are not found in a duchess but in a bishop, who is also passionate about plants coming from overseas. Henry Compton, Bishop of London, had been a botanical collection in the garden of Fulham Palace. In 1713, when he died, Pelargonium inquinans was found in his collection. The first illustration from 1732 was made from a plant growing in the garden of British botanist James Sherard.