Green Circle Growers Blog

Consider Tree's "Sensitivity" Before Planting Bulbs

Green Circle Growers - Monday, September 07, 2009

Garden centers at local stores are setting up their bulb displays, encouraging gardeners to start planning spring gardens. After a long, dreary winter, spring-flowering tulips, daffodils and other bulbs are a cheerful harbinger of the fragrant annuals and perennials to come.

Orange flowers at base of treeBut if you're thinking of planting bulbs under a tree, you might want to reconsider. While some trees tolerate digging around their roots without problem, others are extremely sensitive to any soil disturbance. In some cases, digging can permanently damage the roots of mature trees. Consider the temperament of the tree before you decide whether to root around between its toes. You may be better off forgetting the bulbs and planting shallow-rooted annuals or a shade-tolerant perennial groundcover when spring arrives.

  • Trees that easily tolerate root disturbance are good candidates for bulbs and tuber plants like lilies (Lilium) and hostas. Tolerant trees include arborvitae, crab apple, ginkgo, hawthorn, honey locust, poplar, silver maple, willow and white oak.
  • Trees that tolerate some root disturbance invite plantings of small bulbs, annuals, perennials and ground covers and include hickory, hornbeam, ironwood, redbud, red maple, river birch, spruce, sycamore and white ash.
  • Trees that are highly sensitive to root disturbance can be damaged by planting in root areas. Avoid bulb and tuber plants. Shallow-root annuals, perennials and ground covers such as ivy or myrtle can be tried, or mulch under trees. Sensitive trees include beech, black oak, buckeye, cherry, dogwood, hemlock, larch, linden, magnolia, pine, plum, red oak, scarlet oak and sugar maple.

When planting bulbs, use this attractive marking tip: To mark bulb placement, plant a few low-growing Hens and Chicks (Sempervivum) over bulb areas during fall planting and again in the spring when existing bulb clumps emerge. The succulent rosettes root quickly and resist dislodging by animals. When planting new annuals and perennials, the Hens and Chicks mark areas to avoid.