The most important thing to remember about fertilizing is that you should do it based on a soil test. Then choose a fertilizer that supplements any nutritional deficiencies in your soil.
Cherry trees are low feeders, unlike many other fruiting trees. You can fertilize once per year in early spring before flowers bloom. (You can still fertilize after bud break, but absolutely do not fertilize after July 1.) For young trees, choose a fertilizer that amends your soil, or if that’s not necessary, use a low-nitrogen or general-purpose fertilizer, such as 5-10-10 or 10-15-15, at half the recommended rate. If you’d rather use compost, apply it twice a year, using only a light application.
When applying fertilizer, remember to feed the soil rather than the tree. And be careful not to over-fertilize, which could produce an unbalanced tree that can affect fruit production and leave the tree susceptible to pests and disease.
Although many trees require more nitrogen after they start bearing fruit, cherry trees do not. Check your soil’s nutrients every year, and only apply nitrogen to mature trees if the soil needs it. Remember to keep the area clear of weeds, as weeds will compete with your trees for nutrients.
How often do you fertilize your cherry trees, and what kind of fertilizer do you use? Please tell us about your fertilizer regimen in the comments.