Q.I have a front yard that has several tulip trees, and is on a slight incline, and I cannot get any grass to grow under or around
the trees. Can you suggest what I can plant that would thrive under these conditions? Every year we add dirt and mulch and peat moss, but the grass just doesn’t stay. There is clay very near the surface as well.
Growing under some trees is a difficult environment for gardening. Not only it is shady but tree roots grab most of the nutrients and water. There are some shade plants that may be successful. I'm thinking of barrenwort, Epimedium, which is useful in dry shade. Other plants to consider are Hellebores, aka Lenten rose; hay-scented fern; woodland phlox, Phlox divaricata; wild stonecrop, Sedum ternatum; and sedges like Carex albicans and Carex pennslyvanica. Get starts in small containers or divide plants into 3+ smaller plants if buying gallon sized containers. Tree roots should be disturbed as little as possible when planting which is why you want small plants to tuck into little pockets between roots. Do not add soil on top of roots as this hinders needed air from reaching them. Mulch is fine because it is a looser material and air penetrates it. The first growing season, you'll need to water the groundcover regularly. Next year should need watering only during dry or hot spells. It is easier on the tree if you find a dry shade plant that comes in seeds. Seedlings can send roots between tree roots and spare you the task of planting in pockets between roots. Lamium groundcover comes in many types and colors. Be mindful that it can get out of hand although your dry shade may keep it in check. I would English ivy, periwinkle, winter creeper (Euonymus fortunei) and bugle weed, Ajuga as these are almost certain to invade your grass. The ivy and creeper will also climb the tree which isn't good. I hope one of these ideas works out for you.