Companion Plants: Hardy Geraniums
North Vancouver, British Columbia,Canada
Hardy geraniums, commonly known as cranesbills, are the ultimate in easy care garden plants. They are a diverse and useful group of plants for any garden, and many make excellent candidates for the rhododendron garden, as the majority of geraniums are quite tolerant of most gardening situations. In fact, it is said that there is a geranium for nearly every gardening situation from ground cover to the tiny alpine trough garden, and from the shade garden to the sunny herbaceous border.
The word "geranium" comes from the Greek word "geranos," meaning a crane, because of the resemblance of the geranium seed pod to a crane's bill. The name has been used since the time of Dioscorides in the first century AD when geraniums were grown and used for medicinal purposes. According to records on the subject, various geraniums have been used through the centuries for such ailments as fever, gout, rashes and bruises at a time when herbal medicines played a more important role in our well-being than today. Rather than languishing as an interesting historical footnote, geraniums are increasingly becoming more popular with gardeners as decorative plants.
According to Hortus, there are at least 250 species of geraniums, and most botanists feel that there are other garden-worthy species yet to be discovered. The majority of species come from Eurasia, but if there is a suitable climate anywhere, geraniums can probably be found. There are also many hybrids available to the gardener as a result of natural hybridization and deliberate crosses made by growers. Most geraniums are soundly perennial, especially the most commonly grown, but a few are monocarpic. The annual Geranium robertianum can become a terrible weed so don't allow anyone to make a gift to you of the plant. The common name is "Herb Robert".
Geraniums, for the most part, are good doers in the garden. They are disease free, relatively free of pests, and are drought resistant. They do like good drainage so if your soil is heavy it will need to be amended if your geraniums are to do their best. Given a fairly decent soil, a light side dressing of 6-8-6 fertilizer is all that your geraniums will need to perform well. To keep geraniums looking their best through the growing season they will need to be groomed once or twice; spent blossoms and leaves should be removed.
All geraniums produce attractive flowers and some, such as G. psilostemon with its brilliant cerise-pink and black blossoms, could be described as spectacular. All geraniums are invaluable for the effect their foliage contributes to the garden. Some, such as G. renardii and G. sinense, I would grow just for their wonderful foliage. Also the foliage of some geraniums, such as G. macrorrhizum, in autumn turn brilliant shades of orange, red and maroon.
Here are a few examples of geraniums that would be among my first choices for growing with rhododendrons. The cinereum group of geraniums is one of the best choices for the alpine garden. They make solid little mounds, only about 6 inches tall, that fit in perfectly with the smallest of rhododendrons. There are three cultivars commonly available: 'Ballerina' and 'Lawrence Flatman', which have dusty-rose blossoms with prominent purple veining and dark maroon eyes, and 'Guiseppi Verdi', which has hot pink flowers with a black center. All of them have silvery, attractive foliage.
| Geranium cinereum 'Ballerina'
Drawing by Carol Dancer
Other geraniums I would recommend for small spaces are G. dalmaticum and G. x cantabrigiense.
Geranium renardii grows about 12 to 15 inches tall and equally as wide. It is lovely in flower, but it is also a first-class foliage plant. The leaves are rounded, sage textured, and a soft grey-green colour, making it unique among geraniums. The flowers are white or greyish white marked with violet veins. Stigmas and style are dull red. Geranium renardii will do well in the alpine garden, but I like it tucked in at the front of the woodland border with dwarf hostas, dicentras, ferns and violets. Geranium renardii is my favourite geranium.
| Geranium renardii
Drawing by Carol Dancer
Geranium macrorrhizum is one of the best of all carpeting plants. Although a rapid spreader, this geranium is never invasive. If it exceeds its allotted space, it is very easily pulled out by hand. Geranium macrorrhizum grows about 20 inches tall with soft, frilly five-lobed leaves. If crushed the leaves have a pungent fragrance. My favourite cultivar of this plant is the white flowered form which has a touch of pink in the center of the flower and blooms in early spring.
| Geranium macrorrhizum
Drawing by Carol Dancer
A few other geraniums that I would recommend just to start your collection are G. sylvaticum 'Album', G. platypetalum and G. x magnificum. The latter is well named, as it is quite magnificent with its rich violet flowers and velvety foliage.
Anyone wanting more information on geraniums might want to purchase The Gardener's Guide To Growing Hardy Geraniums by Trevor Bath and Joy Jones. I haven't seen this book, but it is published for the Hardy Plant Society, which should recommend it.
Carol Dancer is a member of the Vancouver Chapter. She has contributed several article on rhododendron companion plants, including "Companion Plants: Ferns in the Rhododendron Garden" (Vol.49, No. 3) and "Asarums As Companion Plants" (Vol.48, No. 4).
Bibliography for Further Reading on Geraniums
1. Bath, T.; Jones, J. The Gardener's Guide to Growing Hardy Geraniums. Portland, Oregon, Timber Press; 1994.
2. Phillips, R.; Rix, M. The Random House Book of Perennials, Volume 1: Early Perennials. New York, Random House; 1991.
3. Thomas, G.S. Perennial Garden Plants. Portland, Oregon, Timber Press; 1990.
4. Yeo, P. Hardy Geraniums. Portland, Oregon, Timber Press; 1992.