I am wondering what some companion plants are for a Malus spp. ether white, black, or red. As a fruit tree, i would think that it needed some additional source of nutrients from leaf litter, but i really don't know.
Not sure what you mean by 'black, white or red' Malus. Can you explain? I am a companion plant sceptic and apple trees will thrive with a wide variety of companions, or none.
Or perhaps you mean Ribes? ie currants - they come in red, white and black. In which case leaf litter would be fine. But no other plants competing around them. Black currants are particularly heavy feeders and enjoy a dollop of manure once in a while.