Advice

RHS Help & Advice

Dividing hostas

Keep hostas growing vigorously by dividing congested pots and borders in early spring or late autumn. Any spare divisions can be planted in new areas or given away to friends.

Hostas in pots

1. Either knock the plant out of its pot or carefully lever the rootball out if the pot’s shape makes this more difficult.

2. Hostas with tough, fibrous roots can simply be divided with a sharp spade or trowel. Place either between the shoots and then slice the clump in two. Large clumps can be split further to leave sections containing five or six shoots.

Cultivars with loose, fleshy roots (shown here) are best teased apart. This can be done by hand or with two hand tools placed back-to-back to lever them in two.

Divide the rootball with two back-to-back hand tools

3. Re-pot using John Innes No 2 compost. The plants should be at their original depth, with the shoots above the soil surface.

4. Water the pot well. Apply a liquid feed in spring to encourage good growth.

Plants in borders

1. Lift the clump using a garden fork.

2. Split the plants in the same way as explained for containers. However, you may find it easier to divide cultivars with loose, fleshy roots with two forks. Place them back-to-back and then push them down into the centre of the clump. Pull the handles inwards to lever it in half. Again, small sections can also be teased out by hand.

3. Replant divided hostas in well-prepared soil that has been dug over to incorporate organic matter, such as garden compost or well-rotted manure. The plants should be at their original depth in the ground, with the shoots above the soil surface.

4. Water plants well and apply a granular fertiliser, such as Growmore or Vitax Q4, to the surrounding soil in spring.

Timely tip

Remember to apply slug and snail controls regularly to prevent the shoots and leaves from being eaten.