September is a transitional month in the garden. The last of summer’s colour is fading, autumn is edging closer, and it’s time to think carefully about what needs pruning now – and what should be left until later. Good pruning at the right time of year keeps your garden healthy, tidy, and looking its best, but pruning at the wrong time can weaken plants or reduce next year’s flowers.
As part of regular garden maintenance, here’s what you should (and shouldn’t) prune in September.
What you should prune in September
1. Lavender
Lavender responds well to a light trim straight after flowering. In September, you can still tidy the faded flower spikes and lightly shape the plant, keeping it compact and bushy. Just be sure not to cut back into old woody growth, as it won’t regenerate.
2. Roses
A gentle prune helps roses face the winter. Remove dead, damaged, or diseased stems, and shorten any long shoots that may be rocked by autumn winds. This keeps plants healthier and prevents wind damage, an important step in ongoing garden maintenance.
3. Fruit trees (apples & pears)
Early autumn is a great time to prune trained forms such as espaliers, cordons, and fans. Removing excess growth allows more light and air to reach the fruits, improving ripening and reducing disease risk.
4. Herbaceous perennials
As many summer perennials begin to die back, you can cut away faded stems and foliage to keep borders neat. Plants such as geraniums, daylilies, and delphiniums benefit from tidying now, though leaving some seedheads for wildlife is always an option.
What you shouldn’t prune in September
1. Spring-flowering shrubs
Plants like camellias, rhododendrons, forsythia, and lilacs are already setting their flower buds for next spring. If you prune them now, you’ll be cutting off next year’s display. Save pruning for immediately after flowering instead.
2. Evergreens
Most evergreens are best left alone as autumn approaches. Heavy pruning now can stimulate soft new growth that won’t survive the winter. If shaping is needed, do it earlier in summer or wait until spring.
3. Stone fruit trees (plums, cherries, peaches)
These should never be pruned in autumn or winter because cuts heal poorly in cold, damp weather, leaving the tree vulnerable to diseases like silver leaf. Stick to summer pruning while the tree is in leaf.
4. Tender shrubs and climbers
Plants such as passionflower, abutilon, and ceanothus should be left until spring. Pruning now leaves them exposed and vulnerable to frost.
Final thoughts on September pruning
September pruning is all about balance – tidying the garden, encouraging health, and preparing for winter, while avoiding cuts that could reduce next year’s growth. When done correctly, it keeps your garden looking cared for year-round and makes ongoing garden maintenance much easier.
If you’d like expert help keeping your garden tidy this autumn, our team can provide professional maintenance tailored to your plants and outdoor space. Get in touch and let’s prepare your garden for the months ahead.