How to divide clump-forming perennials

Herbaceous perennials and bulbs can be divided to increase vigour to the original plant, or create new plants for free. There are several ways to divide plants – but the easiest to divide are those that naturally form clumps. Examples include heleniums, which grow separate rosettes, each with its own rootball, while Ranunculus aconitifolius readily produces new offsets.

Plants with separate rosettes and fibrous roots, such as primroses, can be dug up and divided as their flowers start to fade, while hostas and other perennials with impenetrable root balls can be cut up with a sharp knife or spade. Don't forget spring bulbs, which can be lifted and prised apart as the foliage dies down.

Other plants to divide in spring include asters, astilbe, astrantias, Geranium himalayense and Sanguisorba menziesii.