Why Divide?

After a few years of planting, perennials can begin to die out in the middle and become straggly around the edges. Lifting and dividing the clump can rejuvenate the plant and keep it vigorous; the old, unproductive centre can be discarded, whilst many new plants can be produced from the healthy sections around the outside.

When to Divide

Fibrous or fleshy rooted plants should be divided in their dormant season (from late autumn to early spring); however, do not work in very cold, wet, or dry weather as this will make it difficult for the plants to re-establish themselves. It may be best to leave the division of fleshy-rooted plants until early spring when their buds begin to shoot; this will give you a good indication of the plant's most vigorous areas of growth, and consequently the best sections to re-plant.

How to Divide

Many perennials may be divided simply by pulling sections apart by hand or by using two back to-back forks, whilst plants with solid, fleshy roots should be separated using a knife or spade.

Step 1: Lifting

1. Loosen the soil around the overcrowded clump and then lever it out of the ground using a fork, taking great care not to damage the roots.
2. Shake off the excess soil and remove any dead stems and leaves to make it easier to locate the best points for division.
3. Wash the remaining soil away with water so that you can see which parts are healthy and which need to be discarded.

Step 2: Dividing

Many perennials may be divided by hand; working from the outer edge of the plant, simply pull off small sections, making sure that they have healthy roots and shoots. Discard any older central woody parts, keeping only the young, vigorous pieces with several new shoots. Keep working until you have several little plants, all with buds and roots.

Very tough, fibrously rooted clumps are best divided by placing two border (or hand) forks back to back through the centre of the clump so that their tines are close together and their handles are apart. Move the fork handles gently together then apart to prise the plant into two halves. Work carefully so that the roots are gradually teased away from the rest of the plant; wrenching the forks apart will merely break the roots. Continue dividing the plant in the same manner, ensuring that there is healthy growth in each clump.

Plants that have formed thick, woody clumps or that have solid, fleshy roots should be divided using a clean, sharp knife or spade. Chop down through the centre of the crown of the plant to make several separate pieces, each with at least two or more buds. Trim neatly with a knife to remove any damaged or rotting roots and then dust any cuts with fungicide, following the manufacturer's directions.

Step 3: Re-Planting

Divided plants should be re-planted as soon as possible to prevent them from becoming dried out. The majority should be replanted at the same depth at which they were originally planted, although some may need to be positioned slightly proud of the soil surface to prevent the base from rotting. Make sure that the roots are spread well out before refilling the hole. Firm the soil in well around the roots with your hands and water in well. You will need to ensure that the soil does not dry out completely for the first season after division.