Answer: Some tree roots are more shallow than others so what you're finding is normal for your trees. It's important not to change the soil grade by adding soil or even mulch beneath the trees. Doing so can suffocate the roots which will cause an overall decline in your trees. It's also not a good idea to plant beneath established trees. They will resent competition for moisture and nutrients from other plants and the additional water you'll need to apply can cause additional problems. Since the trees and their roots are already established in the area, the best advice is to build some raised beds for your garden. Keep the raised beds as far away from the trunks and roots as possible and be sure to line them with weed block to keep tree roots from invading the soil. Or, you could garden in plastic containers - either pots or planters. Wish I had better news for you!
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