Now is one of the best times to get out and divide your perennials.
- Divide summer-flowering plants in spring (Mar-May) or autumn (Sep-Nov) when the soil is dry enough to work. In wet autumns, delay until spring. Spring is also better suited to plants that are a touch tender
- Many spring-flowering plants, such as irises, are best divided in summer (Jun-Aug) after flowering when they produce new roots
And this is how you do it:
First lift the clump gently with a garden fork, with plenty of space around to limit root damage (the RHS suggests doing this from the middle of the plant outwards but I find this often too difficult). Shake off excess soil so that roots are clearly visible.
What next? Well, that depends a bit on the growing habit: