Making more and more plants out of those you have already is one of the great something-for-nothing bonuses of gardening. During autumn, many border perennials can be dug up and divided, especially if you garden on sandy, light soil. (However, grasses, red hot pokers, most grey-leaved things and anything that you think is tender should be left intact until late next spring. Divide them now and they may rot off during the winter.)
To divide a plant, dig it up and gently knock the soil off the roots. Often, older specimens will have become woody and tired in the middle, so discard these bits as well as any diseased, damaged or suspicious-looking parts. If the roots are open and stringy you will be able to pull them apart: otherwise, use a clean, sharp knife. Replant in soil that you have refreshed with garden compost, well-rotted manure or a proprietary soil conditioner. A sprinkle of sterilised bone meal around the roots will stimulate growth. Water after planting to settle the soil.
Diary Date: Monday, October 26th, 3 p.m. John Anderson, head gardener at Mount Usher Gardens, Co Wicklow, gives a lecture on Planting and Designing for Winter and Spring Colour at Hosford's Geraniums and Garden Centre, Cap, Enniskeane, Co Cork.