Autumn: seed heads and slowing growth

Autumn is the season of slowing. Flowering finishes, spent spikes turn brown, and the plant puts its effort into the crown and roots. Leaves may thin, yellow or fold over, and the clump begins to look untidy. At this stage that is normal.

September

Flowering tails off. Seed capsules swell on spikes left standing, green at first and then drying to brown. Most leaves are still in good condition.

October

Leaves yellow from the outside inward. Cold nights slow growth, and the clump starts to look tired. Some leaves fall or lie over on the ground around the base.

November

Growth has nearly stopped. The crown is best left undisturbed, with its leaves protecting it until the weather turns cold. This is a time for watching rather than heavy work.

What to look for

• Seed capsules forming on standing spikes, drying from green to brown
• Leaves yellowing from the tips, a normal sign that the plant is slowing
• Soft, dark or slimy leaves at the base, which can point to wet, poorly drained ground
• Dry, papery seed heads that rattle when lightly shaken

Jobs for the season

1. Decide which spikes to keep for their seed heads and which to cut back. Cut the others down to the base.
2. Clear fallen leaves from the crown if they lie tight against it, so air and water can move freely.
3. Check that the ground around the clump drains. If water stands there, a small channel dug away from the base can help.
4. Once the ground has cooled, add a light layer of dry mulch around the clump, keeping it clear of the crown itself.

When most leaves have yellowed, the clump can be left as it is for winter. The seed heads give the bed some shape while the rest of the garden quiets down. The winter page covers what the plant does through the cold.