With summer a fading memory, now is the time to expect the first frosts, cobwebs and autumn colour. And with a regular pruning regime, you not only keep your garden tidy, but you also create dramatic effects with silhouettes and seedheads – and remember that brown is a colour to be enjoyed, too.
Right now, you need to focus on keeping your borders looking great for autumn and winter by getting them into shape. Collapsed, soggy or dying-back foliage should be removed to prevent the build-up of slugs, snails and diseases. Plants such as campanula, helenium and sidalcea will be looking their worst, but pruning back this month will result in a healthy plant that will produce colourful flowers next year. Keep in mind, though, that lavender and rosemary will not do well if they are pruned now.
Resist the urge to prune deciduous trees and hardy shrubs, leaving them until midwinter or very early spring, when the plants are still dormant. This will discourage tender new growth from appearing during cold spells, weakening the plant. Hardy yew is one exception, though. Now is the perfect time to give yew hedges or topiary a final prune before winter, so they keep their neat shape.
More pruning advice for autumn:
Plants to prune now:
Autumn is the perfect time to prune several groups of plants to keep them healthy. Make a few judicious snips now and they will perform better next year.
Hardy geraniums
Prune back to the plant’s crown. If there is no sign of disease, add geraniums to your compost heap, otherwise, burn or dispose of trimmings.
Virginia creeper
Cut back stems of Virginia creeper that are encroaching on windows, doorways, gutters and roofs. Continue this until the end of December.
Dahlias
After the first frosts, and once the plant has blackened, prune back the stems, then lift and store dahlia tubers somewhere frost-free and dry.
Buddleia
Cut buddleia back by about a third to prevent wind rock. Come spring, prune the plant hard to encourage new flowering shoots.
Avoid pruning:
- Dipsacus, eryngiums and martagon lilies: Leave teasel, eryngium and Lilium martagon to create an architectural feature during winter, as well as to feed the birds, in particular finches
- Spring-flowering shrubs and trees: such as magnolia and flowering currant – if you prune these now you’ll remove next year’s blooms
- Ornamental grasses: such as Miscanthus sinensis ‘Kleine Silberspinne’ and Calamagrostis acutiflora ‘Karl Foerster’ will be fading to buff and silver. Leave these to catch the evening sun
- Hydrangeas: faded hydrangea flowers should be left unpruned to protect the new buds forming below from winter frosts and to add texture to the garden
Step-by-step: Cutting back herbaceous perennials
Herbaceous perennials like this nepeta (catmint) will be dying back for winter, but you can give them a helping hand by pruning back dying, tatty-looking foliage and leaves or stems that have signs of mildew, fungus, wilt or leaf spot. Faded stems and leaves can eventually get heavy when wet and rot the plant’s crown, so cut soggy stems right to the ground. This is the perfect time for this job as pruning too early could remove any late flowers. Also, tackling this job now allows you to weed and mulch the soil that was previously covered with soggy foliage.
