I don’t believe there is a fertilizer you can buy. Davey provides a tree and landscape service and come with a large tank truck. They guy walks around with a power injector and shoots the fertilization three feet into the ground every so many feet. The object is to get the fertilizer to the tree roots. The lawn ends up looking like Miss Polka Dot’s dress for a while as grass around the injection becomes Irish green. Other companies have a similar service. It is usually called deep root fertilization.