Re: Growing perennials under a tree
Johanna, If the bed is near the drip line and/or would be only a small percentage of the footprint (rootprint?) of the tree than a shallow raised bed would probably be fine.
However, if you want to plant the entire area or large portion (greater than 30%)under the tree, it is better to dig, BUT dig sparsly between the roots. Try not to damage the tree roots. Plant smaller sized plants in whatever soil pockets you can find. Now that I think of it, growing up we had a VERY large sugar maple in our back yard that my mother planted pachysandra underneath of. She planted little rooted cuttings, so she wouldn’t have to do any digging, just stick in an asparagus fork and slip in the cutting. Every year she would clip cuttings from the thick parts and fill in the thin patches.