What is the best fertilizer for ash trees?

Compost or leaf litter are the best fertilizers for maple trees (Acer spp).

Specifically, maple trees benefit from ground cover that is most like their native habitat. Compost can be applied as a fertilizer along the drip line or as a mulch from about 5 inches (12.5 centimeters) from the trunk out to the drip line. Leaf litter also is a natural fertilizer option.

Otherwise, maple trees need no fertilization schedules if they grow in grass, lawn or turf that is on a regular fertilizer application schedule.