By September our gardens, having performed all summer long, may be getting a little tired, both physically and visually. Mornings are heavy with dew and the evenings contain their first chill. Early-summer flowers have gone over, but later-flowering plants and grasses, particularly in prairie schemes, are at their absolute best. Still, a little tidy up will help to keep everything in check, and this is a perfect time for pruning certain species, such as birch, that will bleed if pruned earlier.
In most cases, there’s not too much to do – September is at the end of the summer-pruning season and, as plants aren’t yet dormant, it’s still a little early for autumn and winter pruning. After a season’s growth, many plants will have already formed next year’s flower buds, so prune with care.
However, early-flowering honeysuckle and other climbers, including jasmine, passionflower and climbing hydrangea, that have just finished flowering, can be pruned now – lightly in the case of the hydrangea, or with a little more enthusiasm if your honeysuckle or jasmine are now outgrown their space.
More pruning advice for autumn:
Plants to prune now:
Any pruning jobs you didn’t get round to in August can still be done this month. You might also want to get ahead a little for the winter to come.
Repeat-flowering roses
If you have varieties that don’t form attractive hips, then deadhead to prolong their flowering into autumn.
Bamboo
Remove the foliage on the lower part of the bamboo stems, to show off their colours and let the winter sun filter through over the coming months.
Yew hedges
Most conifers are best clipped in August, but yew will handle a last neatening up now.
Hebe
Hebes have now finished flowering and can be deadheaded and gently neatened up.
Avoid pruning:
- Forsythia: Any shrub, like forsythia, that flowers on the previous year’s growth should never be cut now or you’ll have no flowers next year.
- Siberian dogwood: If you cut Cornus alba now, you’ll lose the beautiful winter stems.
- Evergreen grasses: These generally don’t need cutting back and provide valuable nesting material for birds in spring.
- Roses that form hips: After flowering, some roses form attractive, glossy, red hips, adding late colour to the garden. These were traditionally made into rose-hip syrup. Hips are also a valuable food source for birds through the winter, giving another reason to value them.
Step-by-step: Pruning early-flowering honeysuckle
Honeysuckle that flowers early is best cut back as soon as it finishes its display, usually about now. The aim of pruning Lonicera in September is to create a pleasing framework on which flowers will form next year. Flower buds set in one growing season and open the next, so never remove all the summer’s new stems or you’ll have no flowers next year.
Instead, aim to create a framework of main stems, tied in to the support, with short shoots of a few buds coming off them. If your honeysuckle needs regenerative pruning, wait until late winter.
