Trees, Shrubs and Roses
A routine check for stem constriction by tree ties on young trees tied to stakes is necessary at this time of year, and ties should be released if they are too tight. Shrubs planted from pots during recent months may still need watering. Make sure all existing weed vegetation is dead before autumn planting begins. This usually means two applications of Roundup or similar glyphosate-based spray. Good results will be achieved now when there is still some warmth.
Take cuttings of tender plants such as marguerites, geraniums, fuchsias and argyranthemums to carry over winter before the end of the month. Continue watering baskets and other containers on a regular basis and feeding too. Stay on top of weeding in flower beds and borders - especially if there has been a new flush after rain. Prevent weeds from going to seed now. It is possible to collect seeds of perennial flowers, if it is desired to raise some new plants, for instance hostas and aquilegias. It is even possible to find a completely new variety from seed.
In late summer lawns often get a boost from nitrogen released by decaying organic material. Fungi and bacteria break down dead roots and other material at a faster rate when the soil is warm and wet and this releases nitrate nutrient that boosts green grass growth. Most lawns green up nicely if there is enough rainfall but a lawn that is not looking good will benefit from feeding with high-nitrogen fertilizers until the end of the month.
Fruit, Vegetables and Herbs
Sow winter lettuce, chard and spring onions. Prune raspberry canes that have finished fruiting, tying the new canes tied into position. If there are too many canes, reduce the number to about ten or fifteen per metre of row. Summer pruning of over-vigorous apples and pears by shortening the whippy new shoots to finger-length can be carried out now to reduce vigour and increase cropping. Tying branches down to the horizontal will also help fruiting in future years. Do not let weeds go to seed to avoid a problem in years to come. Remove apples or pears attacked by wasps to avoid attracting greater numbers and even more damage.
Greenhouse and House Plants
Tidy up all kinds of plant debris from the greenhouse now and be careful not to overwater or to splash water about. From now on, grey mould disease becomes a problem for many greenhouse plants and good hygiene is the best way to avoid it. Continue watering and feeding greenhouse plants. Continue to train and side-shoot tomatoes and cucumbers. Take the tops off tomato plants to encourage the green fruit that is already present to ripen. Some of the lower leaves can be removed to let light at the fruit.