What to sow and plant in September

Head gardener Benjamin Pope is here to make sure your garden looks great all year round. His practical gardening magazine column series continues all year round, and his tips on what to plant in September are a taster of what you can expect. For the full column, subscribe to Gardens Illustrated magazine.

Don't miss our suggestions of the best flowers in September, what gardens to visit and the gardening jobs for the month.

What to plant in September

Soil temperatures and weather conditions are still warm, so now is a good time to make improvements for next year and plant additions to borders, providing there is space. I prefer to plant trees and shrubs in autumn or winter, but planting herbaceous perennials and biennials now will also ensure they establish before winter.

I also begin bulb planting, focussing on early flowering species such as crocus, hyacinths and scillas, along with the first narcissi that put down their roots in autumn. A September planting is also good for woodland bulbs such as erythroniums and trilliums, along with the charming Fritillaria meleagris, all of which dislike being out of the soil where they tend to dry out. Either plant in position or in pots and store outside, planting out when in growth early next spring.

The days are shortening but there is still time to promptly sow hardy greens and salad leaves along with fast-maturing radish. Hardy annuals including cerinthe, cornflowers and poppies can be sown now, though I wait a little longer so that plants don’t grow too large before winter and become more susceptible to frost damage.