September Gardening Tips 2025
September can be such a lovely month, not too hot, not too cold and a wonderful few weeks to spend as much time outside as possible.
At the risk of sounding like a stuck record, because I know I say this every year, autumn really is ‘Nature’s Time to Plant’ every type of hardy plant, from trees and shrubs to climbers, roses and cottage garden plants. With the soil still warm, but damp from autumn rain, plants get off to a much better start, getting their roots down, ready for action next spring. And nature does most of the hard work for you, lessening the need to keep watering recently planted subjects unless the season is unusually dry.
To plant successfully, dig a hole bigger than you ever think is needed. Add a little compost and some slow release fertiliser into the bottom of the planting hole. There are many available from Miracle Gro to fish, blood and bone. At home, we also add some ‘rootgrow’, which is mycorrhizal fungi which helps the roots to develop. Trust me it really works ! Place your plant into the hole. The plant should be planted at the same depth it was in its pot. Refill around the plant with soil and firm gently. Water well and mulch with some bark, composted manure or home made compost.
I love spring bulbs. And now is the perfect time to choose them, as they are freshly arrived in the garden centres. Bulbs are a great symbol of hope and faith in the future. Pick the largest and firmest bulbs you can. Bigger bulbs genuinely result in better blooms. Always choose bulbs from cultivated stock, which ours are, (i.e. they have not been taken from the wild). You can start planting most bulbs in early autumn, but do not plant tulips until October at the earliest. As a rule of thumb, plant bulbs two and a half times deeper than the height of the bulb itself from tip to toe. Tulips in particular don’t like being planted too shallow. Err on the side of caution. Plant in clumps of odd numbers. Something we have started doing at home is planting bulbs in pots and ‘bedding them out’ in the spring as it becomes apparent where there are gaps. Of course you may have been really organised and taken photos when your bulbs were in flower this spring and know where the gaps are already. It is also fun to plant prepared bulbs for indoor flowering at Christmas. Look out for hyacinth and miniature daffodils or narcissi that are marked for indoor flowering.
As it gets cooler, bedding Cyclamen can be popped into pots, hanging baskets and containers for some autumn colour along with Pansies and Viola. Cyclamen will flower their socks off until it gets truly cold. Pansies tend to flower well in the autumn and pick up again in early spring. Chrysanthemums also provide great autumn colour for pots or borders. Hebe, Skimmia and Heather are also really worth their space in containers or borders.
As the autumn sets in it is a good time to tend to the lawn, sowing or turfing a new lawn, repairing worn patches and, as the month goes on and into October, applying some autumn lawn care. More on that next month but some TLC in the autumn really will pay dividends next spring.
Above all I hope you enjoy all that September has to offer in your own outside space
With my best wishes
Sarah
