I have apricot, peach and nectarine trees in the back yard and am wondering when to prune them this spring. I live in north Toronto.
Thank you for contacting the Toronto Master Gardeners.
Fruit trees are generally pruned during dormancy (i.e. between the time when the leaves drop in late fall and when the buds begin to swell in early spring). Ideally, you want to prune immediately before the buds swell, since this minimizes the chance of winter injury. Winter injury occurs when temperatures drop after pruning; the shorter the length of time between pruning and the temperature drop, the greater the injury would be. Therefore, do not prune too early.
But there are exceptions: namely peach and nectarine; these should be pruned during flowering.
Here is a fact sheet on the pruning fruit trees by the Ministry of Agriculture, Food and Rural Affairs for further guidance.