Just any organic fertilizer so your soil remains healthy should work. I might mix it up among corn meal, alfalfa pellets, and soy bean meal at least twice a year.

The processes are the same whether it be a shrub or a grass. The RATE of processing may vary and here and there, some special consideration may have to be given. The soya bean meal will be processed to give up/back nutrients and the plants will process these nutrients. The soya bean belongs to the Legume family which is known for its ability to fix nitrogen and if I were to choose an organic soil ameliorant, SBM would be first.

types of organic foods that boxwoods "like"

Anything! I throw SBM and alfalfa on my hollies, azalea, gardens (with perennials and annuals), clematis, crape myrtle, lilacs, butterfly bushes, and trees.

They all seem to respond to it and the growth rates this year have been impressive without being leggy.