01/09/2026
September is a busy time in the garden. Things can change from summer to the onset of winter quickly, so to save time and work next spring it helps to get on with jobs now and saves having to work in colder conditions.
Keep deadheading and w**ding.
Plant out and transplant biennials.
Divide and replant perennials to ease any congested areas. Later in the month bring tender perennials, such as pelargoniums, inside to protect from the frosts.
Continue sowing hardy annuals for early flowering next year – you'll get bigger, better plants which can flower a good six weeks earlier than those spring sown. For example, briza, bupleurum, calendula, centaurea, Papaver rhoeas, Papaver somniferum, and scabious can all be direct sown now. Remember to keep them w**d free as they germinate.
Clear your annuals as they go over and add them to the compost heap.
Hunt for self-sown seedlings of hardy annuals and biennials, such as English marigolds (Calendula), honeywort (Cerinthe) and honesty (Lunaria), where you’ve had them earlier this year. If they are overcrowded where they’ve sprung up, transplant them or create a line in a cutting patch to harvest flowers next year.
Get wallflowers in place now. These spring-flowering biennials need to get their roots down well before flowering. Pinch out the tips of wallflowers to promote bushier growth.
Sow yellow rattle in wild flower patches as it reduces the vigour of certain grasses.
Now is a good time to start planting your spring bulbs – the ground will still be nice and warm from the summer months, and it gives plenty of time for the new roots to bed in before the spring sunshine arrives.
Inside, have a go at forcing some hyacinths or amaryllis now for colour over the festive season.
Plant pots of smaller bulbs such as muscari, iris, crocus, chionodoxa, scilla and anemones. Keep watered during the winter if we have any dry spells (but lift off the ground to prevent waterlogging which is just as bad) to provide pots full of colour for the spring.
Plant small bulbs in to your lawn. Think of jazzing up an area of lawn or rough grass with crocuses.
Collect seed from perennials and annuals and store them somewhere cool and dry.
Deadhead dahlias. Cut all the spent flowers off to the buds below them. With a little TLC, they’ll keep flowering until the first hard frost.
Prune climbing/rambling roses once they've finished flowering. Remove suckers from the base of roses and trees. Remove any fallen leaves from the base of roses to prevent the spread of disease.
Later in the month plant spring bedding such as wallflowers, primulas and violas for a colourful spring display.
Start planting new perennials as well as trees/shrubs/climbers.
Plant pot grown new trees whilst the soil is still warm and moist.
When you think you’ve harvested your last potatoes, carefully dig over the veg bed, collect those that were still lurking under the surface, and then dig over ready to plant some green manures. These green manures are useful in many ways; they protect the soil from erosion over winter, reducing the potential of any leaching of mineral and nutrients, and also protect soil structure, as well as boosting nutrients when dug into the soil. They also provide a green carpet that helps provide shelter for beneficial insects through the winter, such as ground beetle, and if you leave a patch to flower they are loved by pollinators – Phacelia tanacetifolia for example, is one of the best nectar sources for the honeybee, bumble bee and hoverfly.
Bean and pea plants that have finished their harvest can be cut back, leaving the roots to be dug in to the soil to provide extra nitrogen for future crops.
Continue to feed tomato plants until all the fruits have finished growing and ripening.
Remove any crops that have finished leaving unneeded areas clear – w**ding and tidying for the winter. Keep an eye on your brassicas for butterfly eggs and caterpillars.
Sow Swiss chard, winter spinach, broad beans and hardy peas.
Keep watering winter squash and pumpkins if the weather is hot. This will prevent their growth from being checked.
Once harvested, it's time to start thinking about pruning back your fruit trees and shrubs to maximise yields next year. As a general rule of thumb the sooner this is done after harvesting the better.
Pot up strawberry runners to make new plants for next summer.
Cut back the fruited canes of summer raspberries, tying in the new green canes for next year’s crop.
Try to keep your borders and lawn free of dead leaves. Collect them up in to leaf mould bags, dampen the bags and store in a corner of the garden for a year – then turn out perfect leaf mould.
Continue to feed and water containers and water any newly planted perennials until established.
Order bare-rooted roses for delivery later in the autumn.
Clean out your greenhouse to reduce the risk of pests and diseases overwintering.
Birds, who have been pretty sedentary during the summer, will now start to turn back to the bird tables and feeders in order to stock up for the approaching colder months, so start to top up any food for them regularly. Before you do, give everything a good clean – many birds die each year from parasites and toxic bacteria that can build up in feeders and water containers if not regularly cleaned.
Plant hardy annuals and perennials that attract insects.
Fallen fruit that is starting to go over can be a veritable feast for birds and insects alike. Pop an apple on a fat ball feeder and leave gone over sticky plums and damsons out for butterflies who will adore them.
