Can't address a question about KY Coffee tree, but I have 4 mature (40+ years old) Silver Maples in my rear garden and I have many shade tolerant plants growing under them, including, but not limited to, Native & Evergreen Azaleas, Camellias, Hydrangeas, Japanese Maples, Dogwoods, Hollies, Hostas, Ferns & Spikemoss, Epimediums, Helleborus, Asarum, Heuchera, Iris japonica, Cypripedium, Calanthe, Trilliums, Pieris japonica and many native spring flowering perennials and terrestrial orchids. I constructed raised beds about 5-6 inches deep under them and began planting about 15 years ago. When I encounter a large root, I move the planting hole to avoid it. When I fertilize or irrigate, I insure that the entire area under the canopy of the tree is treated, which alleviates the problem of tree root strangulation. While Maples are credited with a voracious appetite for moisture, many of the largest, most robust plants in my garden grow there, without any extraordinary application of water.
Note-When constructing raised beds under any tree, it is recommended that their depth be limited to Rb

Cool! Great advice Rb.

The KY Coffee has been a trial for years now. I can get some annuals to do great there at first, but when it goes dry, the earth in the bed cracks within a day! Everything there wilts. I think I may resort to pots there this year... even though I think they can be just as tedious to water.

You've got a tremendous stock of plants under your trees. I suspect you have great luck with your zone 7... my zone 5 has hot, dry summers, but since we've had a wet winter, I hope it may have helped my plantings survive. I raised the bed about 4-5" left some space around the crown of the tree (not sure how much off hand-I will check it though). I'm trying a group of hostas, Japanese painted ferns, day lilies, and coral bells. This is their first year so I'm anxious to see how they do. I had great luck last year in the same bed with some blue hyacinth... they slowed down everyone who walked by! Hoping for a great flush again this year.

Thanks for the advice!

Shelley