As September comes into full swing, it’s time to turn your attention to preparing your garden for the cooler months ahead and setting the stage for a beautiful 2026. With summer fading, there are key tasks that gardeners shouldn’t overlook to keep plants healthy and vibrant year-round. A gardening expert and Head of Commercial at Hedges Direct, Helena Jones has shared her seven recommended gardening jobs for September, including which shrubs to prune, plants to bulb and the pests to look out for.
She said: “September is a great time to prepare your garden for winter and look forward to the spring. Top garden jobs to do this month include dividing perennials, collecting seeds and planting bulbs for next spring. Having some wonderful colours and flowery displays to look forward to in spring the following year can help us take on winter with a smile and getting these jobs done now means you can help you to fill your garden the following year without additional cost.”
1. Plant shrubs
September’s cooler weather and increased rainfall make it an ideal time to plant shrubs. This helps roots establish before winter, giving plants a healthy boost for the next growing season. Some great shrubs to plant now include:
- Hydrangeas, which tolerate sun or shade depending on the variety
- Cotinus Coggygria (Smoke Bush) with its burgundy leaves and fluffy flower spikes
- Ceanothus, a beautiful blue-flowered shrub that thrives in full sun and well-drained soil
2. Tend to drought stressed plants
If your garden has suffered from dry spells, now’s the time to give those plants a deep watering.
The expert said: “If you have had very little rain in your garden over the past few months, some of your plants may be looking a little worse for wear.
“Make sure to give them a deep watering, and prune off any damaged material. Apply a thick layer of mulch around the base of the stem; this can be bark or wood chip, compost, or well-rotted manure.”
3. Collect seeds to grow next year
Gather seeds from trees, shrubs, annuals, and perennials to grow next spring. Acorns, conkers, hawthorn, rowan, blackthorn, hazel, and lavender seeds are particularly easy to germinate.
Remember to remove seeds from fruit and dry them on a paper towel before storing them in a cool, dry place.
4. Plant flowers and spring bulbs
September marks the start of bulb planting season. Bulbs planted now can establish roots before the soil becomes too damp in winter, protecting them from rot. Some great bulbs to plant this month include allium, crocus, daffodil, tulip, snowdrop, and grape hyacinth. Ms Jones advised applying a layer of mulch to the soil to protect your bulbs against frost.
5. Divide perennials
Dividing perennials is an easy way to increase your plant collection and keep existing plants healthy. Gently dig up and separate clumps according to each plant’s needs, then replant and water thoroughly.
Ms Jones said: “One of the most productive September gardening jobs is to lift and divide perennials. This can instantly give you more plants and is easy to do. Make sure to divide perennials according to their individual needs; most can be dug up and then gently teased or cut apart, but it’s important to check so you avoid damaging your plant. Ensure to water in well once you have replanted both.”
6. Prepare your lawn for winter
Continue mowing, Ms Jones said, but make sure to raise your mower’s cutting height to keep grass healthy. If your lawn is compacted or mossy, September is a great time to scarify, aerate, and fertilise while the grass is still growing strong. This will help it survive winter’s harsh conditions.
7. Look out for pests and diseases
Watch for signs of powdery mildew, a fungal disease that weakens plants, by removing affected leaves and pruning to improve airflow. Make sure to remain alert for honey fungus, as well, which is a serious root disease that requires removing infected plants.
Lastly, Vine weevils can also damage roots and foliage and it looks like a sort of beetle with an elongated head. Ms Jones said September is a good time to applying a nematode treatment to help control their populations.
However, she stressed that the best long-term solution is creating a wildlife-friendly garden that encourages natural predators like birds, hedgehogs, and frogs.