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Dividing perennials

Ideally, perennials should be lifted, divided and replanted every three to five years. You'll be rewarded with healthy, vigorous growth and a crop of new plants.

When to divide

Plants should be divided when they're dormant, in late autumn or early spring. Fleshy-rooted perennials, such as paeonies, should be left until the end of their dormant season in late spring, before being divided. Their buds will begin to shoot, which will indicate the more vigorous areas of growth, and therefore the best way of dividing up the plant.

What to do

How to divide

• Lift the plant by loosening the surrounding soil, taking care not to damage the root system.
• Once lifted, shake off as much loose soil around the roots as possible and remove any dead leaves and stems with secateurs.
• Make sure all buds are visible before dividing.

Fibrous-rooted plants

• Place two hand forks back-to-back near the middle of the plant.
• Gently push the handles back and forth so that the prongs gradually tease the plant apart.
• Repeat the process with each portion to divide the plant into more sections, making sure each section has a healthy bud.
• Discard the old, woody growth from the centre of the plant.
• Some fibrous-rooted perennials, such as primula, form a loose crown of many stems, as shown in the image on the right, and can be simply pulled apart by hand without damaging the plant. You can also take off separate stems growing at the edge of the plant, just make sure each portion has its own roots.

Fleshy-rooted plants

• Plants with fleshy roots should be divided with a spade.
• Make sure the new shoots are visible before dividing.
• Trim each division with a knife, discarding any old, woody material and damaged growth.

Replanting

• Replant divisions as soon as possible, making sure that the roots don't dry out. In general, divisions should be planted at the same depth as the original plant, leaving enough space between plants to develop.
• Ensure that roots are evenly spread out in the planting hole before gently firming the plant in.
• Water the base of each division immediately after planting, and keep the plants well watered while they settle in.

Watch video

Follow Joe Swift as he divides and replants a perennial at Greenacre.

Five to divide

• Aster
• Hemerocallis
• Primula
• Japanese anemone
• Heuchera