Why is my tree failing after applying mulch?

It sounds as if you might have problems with soil fertility and/or root collar issues. You should be able to clearly see the root flare at the base of the tree after planting and mulch application. If you cannot see the "knees" of the roots at the base of the tree I would excavate around the base until the lower stem is uncovered and the flare is clearly visible. Taper back the excavation to keep it from filling back in. If you would like to see one of our specialists, you can click here to make an appointment.