Plant profile: species pelargoniums John Hoyland recommends the best species and primary hybrid pelargoniums
Species plants and primary hybrids have a delicacy that is far removed from the blowsy blooms normally associated with the Pelargonium genus
Gardeners are always on the lookout for something new. Every year ‘improved’ forms of old favourites or strange hybrids in unexpected colours are introduced. In the rush for novelty, species plants, the wild ancestors of garden hybrids, are often overlooked. When I was taking my first, tentative, steps down the gardening path in the 1970s, I remember a nurseryman asking why I would be in interested in species plants, which were all ‘dull and weedy’, when I could have colourful modern hybrids. Had I been more articulate (and know what I now know) I would have replied that species plants have a robustness often lacking in their descendants and that their simple flowers have an elegance lost in breeding hybrids. In the past couple of decades garden designers have also realised that species plants combine well with other plants to create a more natural look in the garden.
The difference between a species plant and a hybrid can be so huge that the two look unrelated. This gap is probably greatest between the gaudy flowers of hybrid pelargoniums (the popular ‘bedding geraniums’) and the subtle allure of the wild forms of the genus. There will always be a place for blowsy plants in my garden, but the discreet charm of species plants is much more welcome.
There are about 17,000 pelargonium cultivars, all derived from just a few of the 280 species. The genus is diverse and includes annuals, perennials, succulents, shrubs and tubers that range in height from a few centimetres to several metres. The flowers are irregularly shaped, with two upper petals and three lower ones. The genus encompasses an enormous variety of leaf shape and textures.
One of the traits that attracted breeders is that many of the species are both floriferous and long-flowering. The first I grew, P. ionidiflorum, is covered with sprays of flowers from early spring and only stops flowering when I cut the plant back for
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overwintering. This ability to produce flowers over a long period can be seen in modern hybrids.
Many species pelargoniums are grown for their scented leaves rather than for their flowers. The most common are rosescented species, such as P. capitatum, and citrus-scented ones, such as P. citronellum, which have formed part of complex breeding programmes to produce scentedleaved pelargoniums. Peppermint, balsam and spice perfumes are also found in species pelargoniums. The scent from the wild plants is far stronger than that of the cultivars and hybrids, and I remember a warm evening in the Western Cape when just a few plants of P. citronellum filled the air with the sharp smell of lemon.
More than 80 per cent of pelargoniums are native to the south western tip of South Africa although P. triste, the first to arrive in Britain in the early 17th century, was known as Indian storksbill in the belief it came from India. The powerful night-time scent of its tiny flowers – reminiscent of jasmine – caused a sensation.
Perfumed flowers is a trait of some species pelargoniums that has been lost in breeding hybrids. Sometimes the scent is soft and faint, as in the fringed flowers of P. caffrum, and sometimes so heady that it is almost overpowering, and not always pleasant P. gibbosum, an unusual-looking plant with succulent stems and leaves, has flowers with a particularly strong perfume that a friend has likened to toilet cleaner.
In the wild very little hybridisation occurs, even when species are growing close to each other, but as early as the start of the 19th century, plant collectors began crossing different species. The results known as primary (or species) hybrids tend to closely resemble their parents, but the same cross can produce different plants. Both the fiery-red P. ‘Ardens’ (see page 53) and the larger purple-red P. ‘Schottii’ (page 58) are from the same parents. Both were once seen only in the collections of enthusiasts but are now, thanks in part to micropropagation, widespread and popular.
These species and primary hybrid pelargoniums don’t have the razzamatazz of their highly interbred descendants but they provide a diversity of colour, texture and scent that is perpetually captivating. • John’s recommendations for species pelargoniums continue over the next six pages.