Low winter temperatures or late frosts can damage flower buds or blooms. Cover your tree to combat any damage due to lower than average temperatures; you can buy garden fleece to cover your plant or use plastic or blankets or any other suitable covering.
You will need to carry out some form of pest control on your trees, as a variety of different bugs can affect peach trees. Some of the common infestations include tarnished plant bug, plum curculio, stink bug, peach tree borers, European red mite, oriental fruit moth and Japanese beetle. Set up a regular spray program to combat these pests if you wish to grow peaches successfully.
Some of the common diseases that may affect your peach tree are bacterial leaf spot, peach leaf curl and powdery mildew. Bacterial leaf spot is indicated by small reddish spots and holes on leaves and can be treated by pruning out infected areas and fertilizing the tree. Signs of peach leaf curl on your tree will be red curled and distorted areas on the leaves. Powdery mildew will cause a white coating to appear on leaves. Both should respond to fungicides applied before bud break; pruning the tree to allow more air circulation will help ward off powdery mildew.
Pruning your tree properly and thinning fruits will increase the size of mature peaches considerably. Pruning your tree allows more light to reach the branches and developing fruits. Prune out vigorous upright growth, cut out dead and diseased wood and cut out all broken branches and twigs that cross over each other. If there has been no winter frost damage to your peach tree, it will set more fruits than the tree can support and you must thin these. As soon as the growing fruits are about the size of a quarter, thin them out by hand so they are spaced about every 8 inches or so, as this will allow for optimum fruit development.