Written by: Crocus Head Gardener Ashley Edwards
September is a time of gentle shifts in the garden. The air takes on a different quality, the earthy scent reminds us that autumn isn’t so far away. Mornings can feel slightly crisp, evenings cooler, and the first few leaves begin to fall (although this has been hastened by the dry weather this year!).
It’s a good time to think about your garden space. How has it looked to you this year? What’s thrived and what's struggled? Is it resilient, or does it require a large amount of labour from you? Perhaps you want to be more hands on and start a new project? September is also a great time to look ahead to next year and plan your spring bulb planting.
I’d like to share with you some projects and ideas for gardening in September.
Pruning
You can prune many of your evergreen shrubs and hedges this time of year. A September prune is more about lightly shaping and tidying than hard formative pruning. What you want to avoid is encouraging lots of new shoots as these can be damaged by the upcoming frosts.
Late flowering shrubs like hardy Hibiscus, Cistus and Abelia, can all be pruned to shape in September. Once the flowers have finished, use clean sharp secateurs or hedge shears to take spent flowering shoots back to the next set of healthy leaves. This will keep the shrub looking neat and encourage bushy growth next year. If you do need to rejuvenate a shrub by performing a hard prune, this is best done in late winter or early spring.
Evergreen hedges like yew, buxus, laurel and holly can also be pruned this time of year. Again, you don't want to do any hard pruning, but instead just take off the soft summer growth to reshape. Use hedging shears for small hedges or topiary or get yourself a pair of battery powered hedge trimmers to make quick work of it. Always check for nesting birds as some species will nest later in the year, it is illegal to disturb a nesting site. Keeping your hedges clipped will create a formal backdrop for other plants, and produce a dense hedge that is good for blocking out noise, pollution and undesirable views.
Some trees can be pruned in September. Birches can benefit from a crown lift now as the flow of sap has slowed down and bleeding is less likely. Hornbeams can also be crowned lifted in September. It’s sometimes easier to see what to remove when the leaves are still on the tree, casting shade. The purpose of crown lifting is to allow light to penetrate under the canopy of the tree, opening up opportunities for underplanting, creating a clear tree trunk and avoiding obstructions. Any dead branches will be more obvious this time of year too, so remove these with a sharp pair of loppers or saw.
If herbaceous plants have flopped over in winds and died back, you can prune these to the ground. Try the chop and drop method where you leave the well chopped material on the soil surface to be composted by microorganisms. Leave any seed heads of grasses, alliums and other structural plants, for winter interest. Resisting the urge to cut and tidy everything also provides essential habitat for insects. If you do need to tidy, do it in sections to allow any creatures the chance to move on.
