Maple trees (Acer spp.) are excellent garden anchors and can be good companions to a variety of plants. The key to creating an effective planting scheme around a maple tree is understanding the requirements for such plants. The plants should be shade tolerant -- the degree of tolerance depends on how close they will be to the tree's trunk. The plants should also be fairly shallow-rooted, as they will have to be installed in pockets between tree roots.
A tree's drip line is the area under the tree where rainwater falls from the branches. It is also where most of the roots lie. Drip line boundaries consist of an imaginary circle on the ground equal to the circumference of the tree's crown. Drip line areas increase with the size of the tree. Plants closest to the line receive the most light; plants farthest from it (and closest to the trunk) receive the least light. Specimens labeled "part shade" should be planted closer to the drip line boundary. Those labeled "full shade" are happiest closer to the trunk.
In spring, crocuses (Crocus spp.) and daffodils (Narcissus spp.) can flourish before maples leaf out, especially near the outer edge of the drip line. The best varieties are early flowering ones like "Minnow" (Narcissus "Minnow"), a daffodil hardy in U.S. Department of Agriculture plant hardiness zones 3 through 9, and featuring yellow flowers on 7-inch stems. Silvery purple tommasinianus crocuses (Crocus tomasinianus) grow about 4 inches tall and naturalize freely. They also bloom early and are hardy in USDA zones 3 through 8.
Shade loving groundcovers can flourish throughout the drip line area. Lenten roses (Helleborus x hybridus), hardy in USDA zones 6 through 9, feature long-lasting spring blooms and also serve as an evergreen ground cover. Coral bells (Heuchera hybrids), generally hardy in USDA zones 3 or 4 through 8, and foam flower (Tiarella wherryi), hardy in USDA zones 3 through 7, bear dainty spring flower stalks and colorful leaves. "Obsidian" coral bells (Heuchera "Obsidian"), with dark purple leaves and "Lime Rickey" coral bells (Heuchera "Lime Rickey") make a wonderful pair.
The area around maple trees is ideal for colorful, low-growing Japanese painted fern (Athyrium niponicum var. pictum), hardy in USDA zones 3 through 8. The fronds, which grow to about 12 inches tall, combine silver, maroon and gray green. Used in masses, the effect is a swirling tapestry. Use the species in conjunction with the "Ursula's Red" variety of Japanese fern (Athyrium niponicum var. pictum "Ursula's Red"), hardy in USDA zones 5 through 8. "Ursula's Red" has red central veins and leaf tips that contrast with the silvery foliage. Japanese ferms thrive even in full shade.