How to grow hardy geraniums
Hardy geraniums are one of the easiest most troublefree perennials
Herbaceous border at the Lakeland Horticultural Society Holehird Gardens, Windermere (pictured above)
These lovely hardy perennials are an absolute must in the herbaceous border, they are so reliable and require almost no maintenance, just a quick shear after flowering. But be warned some of the larger ones can become invasive and others do seed freely so you will find seedlings popping up all over the garden. There is a huge array, approximately 422 species, which tolerate a wide range of conditions from small alpines to about 75cm (2’6”) tall. They originate mainly in temperate regions but some do come from tropical mountainous regions, however the majority come from the eastern Mediterranean.
The majority prefer a little shade but the alpine varieties ideally need full sun. Geranium sylvaticum and its cultivars will tolerate very dry conditions, the alpines need to be well drained but the others are happy in any normal garden soil. Most of them are single flowered but if you are prepared to search there are one or two double forms; ‘Summer Skies’ is a lovely double pale lilac reaching a height of 45cm (18”) and G. pratense ‘Laura’ is a pure white double which grows to 60cm (24”) in height.
Mixed border Lakeland Horticultural Society, Holehird Gardens, Windermere
Any good humus rich, well-draining soil in semi-shade is acceptable to most varieties. The alpines need a well-draining spot in full sun. Don’t enrich the planting hole as this will just lead to a large straggly plant with fewer flowers. Water well after planting.
They need very little aftercare once they become established, just keep an eye on the watering for a couple of months after planting especially if the weather is warm. Once the first flush of flowers has gone over cut them back almost to ground level and they will flower again in late summer.
Many will self-seed so just pot these up and plant out when they have made a decent sized plant. Alternatively you can lift and divide in spring; this is especially useful if the plant is old and begun to loose vigour, prise away any old dead patches and replant the young portions.
Pests and problems
They are really trouble free as rabbits don’t like them and slugs will eat everything else first. They are not susceptible to disease but can occasionally succumb to mildew but nowhere near as bad as clematis or phlox.
- ‘Ann Folkard’ - deep purple with an almost black eye and lime foliage; 50 – 60cm (2’8” – 3’)
- ‘Ballerina’ - pale pink; 20cm (8”); alpine so needs full sun and good drainage; long flowering period from April
- G. oxonianum ‘Hollywood’ - very pale pink with dark veins; 45cm (18”)
- G. pratense ‘Delft Blue Butterfly’ - unusual white with blue splashes; 60cm (24”)
- G. sanguinium var. striatum - pale pink flowers on a large tight mound; 60cm (24”)
- ‘Kashmir Blue’ - mid blue, looks like the one you see growing wild on roadside verges; 45cm (18”)