Head gardener Benjamin Pope shares his advice for what you should be planting in September
September can be a magical month for the gardener. The weather in the UK can still be
hot, although the sun’s intensity has gone, making things feel just that little more relaxed.
After a busy spring and summer, I relish this slower pace, where rose flowers are left to form hip, and drying seedheads of angelica, monarda and veronicastrum mature to create interesting structure for the months to come.
For now, I don’t mind the borders looking a little chaotic and loose, as long as they hold some warm, rich colours that reflect the approach to autumn. Brassy yellow Helenium ‘El Dorado’ shouts loudly from the borders, while Crocosmia ‘Miss Scarlet’ and Bistorta amplexicaulis ‘Fat Domino’ are ablaze with rich scarlet flowers.
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What to plant in September
Plant herbacious perennials and biennials
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.
Bulb planting in September
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.
Sow hardy greens and salad leaves
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.
Here’s spring-flowering bulbs to plant in autumn