The amazing fall color of our forests this year has many homeowners thinking about adding a shade tree to their landscape. The brilliant foliage of deciduous trees can certainly add curb appeal in any neighborhood. Some of the best arboreal performers this autumn were maples, hickories, sourwoods, dogwoods, ginkgos, and black gums.
There are a few good reasons to plant shade and fruit trees just before ground temperatures drop significantly. Trees and many other woody landscape plants actually perform better when they’ve had a few months to establish their root systems before the spring warm-up. After it’s been watered thoroughly, a fall-planted tree needs very little supplemental watering, thanks to the cooler weather conditions. Plus, December afternoons in North Carolina can be ideal for planting projects.
A frequent question from residents in older, inner-city communities is how to deal with compacted soil when planting trees. Soil compaction is quite common in clay soils of the Piedmont region. New subdivisions may be essentially devoid of topsoil, as the land is graded to impermeable rock layer for construction. When a house is built, an urban soil backfill is spread on the lot, and that may be problematic for landscaping.
Studies of tree installations reveal that one should strive to dig a wide hole for planting that is three to five times larger than the diameter of a tree’s root ball. A wide planting pit that is no deeper than the root ball helps to address the soil compaction issue. Getting the tree to form new roots into well-aerated soil is the key to successful tree planting. To facilitate root development, landscape contractors often use a backhoe to make trenches that radiate out from a tree pit; these are later refilled with topsoil, providing a well-aerated rooting zone.
Although soil amendments used at planting time have shown very little benefit for improving tree establishment, studies confirm that any method aimed at relieving compacted soils is helpful. Amendments should not exceed 20 percent of soil backfill, and they should be coarse textured. Mulching trees after planting improves survivability, as well as conserving moisture and reducing weed competition.
Similarly, soil compaction problems can cause tree decline in parks, older developments, and in home landscapes. A common remedy for compaction in yards is plugging the lawn, using core aerating machines borrowed from an equipment rental company or employed through a lawn care service. It is best to aerate deeply at the drip-zone area of the tree, not directly under the tree canopy. Follow up this treatment with a topdressing of leaf compost or screened topsoil for better air infiltration.
It never hurts to stake a new tree for the first four months, especially going into the winter. Always remove stakes promptly once the tree is established to improve its durability.