I have several young (1-4 years old) fruit trees and am considering planting nitrogen fixers around/underneath:
- white clover (ground cover)
- lupine (herb layer)
- siberian pea shrub (shrub layer)
It seems intuitive that the N-fixers will only provide a benefit as far as their roots extend.
I don't want to damage the tree roots by digging too close. I think the tree roots will extend further outward over time as the trees grow.
Does it make sense, and is it safe for the trees, to dig planting holes for the lupine just outside the drip line of the trees? Or is there more potential for harm than good?
If I go to the effort of digging there (digging isn't easy here), I'd probably amend the general area with manure.
Similarly with the clover, I'm thinking about scraping away the mulch and scattering seed underneath the trees then covering with 0.5" or so of composted manure. (Or covering the area with 1-2" of compost and spreading seed there.) Are there any potential problems with this?