x cantabrigiense & macrorrhizum
Valuable for providing low growing evergreen (or nearly) groundcover and spring flowers. They are one of the most useful for providing cover in poor soils, especially under shrubs, trees or hedges. This group are the most useful spreading cranesbills you can find.
Geranium macorrhizum is the larger species and typically gets to 20cm-30cm tall in flower, and most forms spread across the ground by underground stems that come up on the edge of the existing plant. The older varieties are mostly evergreen, with autumn winter foliage colour, and tend to have a good display of white to magenta flowers in mid-late spring. In more recent years some largely deciduous forms have been introduced that are less spreading but a bit more delicate. All forms have leaves and stems that are scented, mostly of a spicy aroma.
Geranium macrorrhizum can hybridise with the diminuitive relative Geranium dalmaticum to create the hybrid species Geranium x cantabrigiense which performs the same job in the garden as Geranium macrorrhizum, but on a slightly smaller scale. Most forms 15cm-20cm tall, and pretty well all evergreen they provide a very good, uniform groundcover suitable for edging beds, under shrubs or trees and even for larger rockeries.
Both Geranium x cantabrigiense and Geranium macrorrhizum are good in sun or light shade, in any soil that is not too dry or damp. They are both suitable for growing on banks and winter hardy throughout the UK.