All About Tree Fertilizers
When to apply
Nutrients are absorbed from the soil by tree roots and need to be available during periods of root growth. Maximum tree root growth occurs in spring during the weeks before bud break and slows once shoots begin to elongate. A second growth period occurs in late summer after shoot growth and continues into fall until the soil temperature cools. Fertilizers should be applied in early spring before shoot elongation (before and during crab-apple bloom) or late fall (just as fall color begins to develop) until leaf drop. Fertilizing in mid to late summer should be avoided because this may stimulate a new ﬂush of growth that will not acclimate properly and be susceptible to a fall freeze.