Most herbaceous perennials may be divided now, although not asters, ornamental grasses, red hot pokers, or anything that is slightly tender. Shear off the old, tired foliage and flower stalks and dig up the plant. Prise apart the roots and throw out any woody or unproductive parts. Replant in soil that has been refreshed with garden compost or a proprietary soil conditioner. Add a dash of fertiliser (chicken manure pellets; blood, fish and bone; or granular plant food) to the planting hole.
Plant evergreens and conifers now, while there is still some warmth in the soil, so that they can settle in before winter. Make sure to dig out any perennial weeds first and add some compost or soil conditioner to the planting hole. Check the eventual height and width of the tree or shrub, and don't plant too close to other plants or to walls or paths.
