Keep weeding; most perennial weeds are susceptible to weedkiller this month and systemic weedkillers will carry on working throughout the winter.
Clear any debris and diseased material from your garden, because if left it may reappear next spring.
Give the greenhouse a thorough clean to prevent pests from making a home in that lovely warm environment.
If your soil is heavy clay, start digging it over now whilst it is still relatively dry. Add plenty of organic matter to improve the quality and pea shingle to improve the drainage. It can be left in a pretty rough state over the winter when the cold will break the lumps down, making spring planting easier!
Ensure trees or shrubs planted in the last couple of years on lawns or in areas of rough grass have a circle of clear earth around them – this MUST be kept clear or grass will prevent essential moisture getting through. Mulching with bark or compost will help.
Raking (or scarifying) the lawn will keep the levels of dead moss and other debris at an acceptable level. Aerating (or spiking) the lawn will allow better movement of air and water in the roots.
September is the prime time for planting bulbs for next spring.
Plant within a week of buying, in a location with good drainage. Bury bulbs at twice the depth of their size.
Use them to fill gaps in beds and borders, in formal gardens, in pots and containers, under shrubs and trees or naturalised in grass or woodland.
For a natural look, scatter handfuls of bulbs and plant them where they land.
Make sure tall flowers are supported.
Once perennials have finished flowering, cut them back and divide large clumps by lifting carefully and separating down the centre
Buy and plant out violas, wallflowers and primulas now.
Remember not to grow wallflowers and ornamental cabbages in the same spot two year running; they are brassicas and need rotation to avoid the root disease ‘clubfoot’.
Clip back hedges such as privet, hawthorn, beech before mid September.
Keep deadheading roses regularly. Prune climbing roses.
Lightly trim over lavender bushes with hedging shears. More drastic pruning to rejuvenate old plants should be left till March or April.