September Gardening Tips

We wonder what September will bring us as the days begin to shorten – will we get an Indian summer? Or will we get colder nights bringing those autumn mists and dew on the lawn? Whatever the weather this month, the harvest has begun and apples, pears and vegetables are ready to be collected and stored for the months ahead. Autumn colours are starting to develop, showing us the glorious shades that are to come and, whilst there has been a slight lull in activity over summer, there suddenly seems to be a lot to be getting on with.

Plant evergreen shrubs – planting evergreen shrubs in autumn is beneficial in several ways. At this time of year, the soil is still warm and moist, meaning the roots can establish before winter sets in, getting the plants off to a flying start come the spring. While there should be plenty of moisture in the soil, pay attention to watering as September can be dry.
Prune climbing roses – whilst rambling roses can be pruned in late summer and early autumn, so can climbing roses. This is ideally done as the flowers start to fade but if they are still going strong, then delay until next month. First, remove any dead, damaged or diseased stems. Then, locate the new shoots growing from the base of the plant and tie them in. If there are few basal shoots, prune all the side shoots from the existing framework of branches to two or three buds. Any long, whippy shoots can be shortened and tied in to prevent strong winds from damaging them. Any renovation work is best done in winter.
Autumn lawn maintenance – towards the end of September, many gardeners begin work on their lawns to reinvigorate it. Focus on scarification and aeration. Scarifying is removing what is called ‘thatch’ from the lawn. ‘Thatch’ is dead grass and other debris that restricts air movement and drainage around the grass encouraging moss and weeds. Use a spring-tinned rake to remove the thatch, or if you have a large lawn, consider a powered scarifier. Aeration relieves the compaction of the soil, allowing air to reach the grass roots by creating small holes in the soil surface. This can be done with a garden fork or a powered aerator but don’t worry if you have too many other garden tasks as it can wait until the new year.
Plant spring flowering bulbs – this is the main month for planting spring flowering bulbs except tulips, which is best done in November. Look out for Muscari ‘Grape hyacinth’, daffodils, Anemone blanda and Iris histrioides. If planting in borders, aim to plant in groups of at least six for a better display. Plant the bulbs to a depth of at least twice their height. Place the bulbs in the hole with their shoot facing upwards and space them at least twice the bulb’s width apart.
Lift tender perennials – plants like osteospermums, gazanias and pelargoniums, which are tender, will need lifting before the frosts come and taken under cover for protection. Give the plants a trim and remove any yellowing leaves and spent flowers. Pot them up and keep them in a cool frost-free place over winter, giving them just enough water to keep ticking over.
Take hardwood cuttings of roses – select a shoot about pencil thickness and roughly 30cm long. Remove the soft-growing tip and all but the top three leaves. Trim the base of the cutting immediately below a leaf joint. Place in the soil with good drainage up to two-thirds of their length and firm in. The cuttings will root ready to be transplanted to their flowering position next autumn.
Stop feeding permanent plants in containers – if plants in containers, such as shrubs, trees and fruit trees continue to be fed, they will produce soft growth now which can be damaged in the winter months. So stop feeding with general fertilisers. One last feed of sulphate potash or rock potash will ripen the wood, helping them to stand up to the rigours of winter.
Sow a winter variety of lettuce – sow in shallow drills and cover with cloches. When the seedlings are large enough to handle, thin them out to about 15 cm apart. They can be harvested from January onwards. A good variety to sow is ‘Winter density’.
Prune blackcurrants – if you wish, from now and through winter, blackcurrants can be pruned. Wait until the leaves have begun to fall so that you can see what you are doing. Cut around a third of the oldest stems down at the base.
Begin lifting root vegetables – vegetables such as beetroot, carrots and parsnips can be lifted and stored for winter. Only store undamaged roots. Lift the roots and twist or cut off the foliage leaving a few centimetres of stem. One tip is to store them in boxes between layers of dry sand or potting compost. This prevents them from drying too quickly and keeps them in the dark, discouraging growth. Store in a frost-free place. Inspect them regularly and throw out any showing signs of rotting.

If you have any further questions or would like some assistance with your garden, then visit our Nicholsons Garden Maintenance webpage.