Plants for Tree Wells

Requirements

• When selecting plants for tree wells, it's important to consider the size of the well and whether the tree is evergreen or deciduous. Evergreen trees cast shade year-round, whereas the winter-bare branches of deciduous trees admit more light in spring before they leaf out. Trees require large amounts of soil and nutrients, so shallow-rooted plant specimens that can fit into soil pockets between large tree roots work best. Low-maintenance perennial plants often make good companions for trees. Those that spread readily will eventually form a living mulch in the tree well, helping conserve soil moisture.

Spring Plants

• Fall-planted bulbs provide spring color in tree wells. For wells around deciduous trees, small bulbs such as crocus, snowdrops and miniature daffodils fit into narrow planting pockets and will increase over time. Ajuga retans, or bugleweed, tolerates even dry shade and produces bright-blue spring flower spikes. It works equally well under deciduous and evergreen trees, and varieties with colorful leaves provide interest during summer and fall. The latter is also true of yellow archangel (Lamium galeobdalon), which provides attractive variegated leaves, yellow snapdragonlike flowers and a spreading habit.

Summer Plants

• Hostas grow well under trees and are available in a variety of sizes and colors. Traditional "August lilies" (Hosta plantaginea) produce large, scented white flowers in midsummer. For deciduous trees with open canopies or high lower limbs, big-leaf geranium (Geranium macrorrhizum) provides spring flowers and scented green leaves that turn crimson in fall. Shade plants such as astilbe, heuchera, tiarella and heucherella work well under deciduous trees, provided they have sufficient moisture. Keeping them healthy may require supplemental watering during summer months. The low-growing Cornus canadensis provides white flowers, whorls of green leaves and red fall fruits.

Winter Plants

• Ivies, especially the variegated varieties, provide evergreen color in winter. For late-winter and/or early-spring flowers, try members of the hellebore family. Helleborus niger, or Christmas rose, bears large, white, five-petaled flowers any time from January through early March, depending on climate. Helleborus orientalis flowers in late winter or earliest spring in colors ranging from pale green to shades of white, pink, red and darkest purple.