GREEN AND GROWING
Go Plant a Tree
We’ve sprung forward into spring and daylight savings time. Now, it’s tree savings time—the second-best time of the year to plant trees (late fall is best). We may think we know how to plant a container grown tree, but the old techniques contained some advice that data-based research has now disproven. The current best practices are:
- Locate the point where the topmost root emerges from the trunk. This should be level with the soil in the pot, but it might not be. Remove any soil above this junction if it is buried.
- Measure the distance between the topmost root and the bottom of the root ball. Dig your hole about 10 percent less than this distance. For example, if the distance measures 1 foot, dig your hole .9 feet deep, a little less than 11 inches. Make the hole as wide as possible, at least 1.5 times the width of the ball and preferably more, much more. Keep the walls of the root hole rough; smooth sides are hard for roots to penetrate.
- Remove the tree from the container and inspect the root ball carefully. This will seem unkind or even dangerous, but prune or forcibly untangle all encircling roots. If you don’t do this now, the roots will grow round and round in the planting hole, strangling themselves and the tree.
- Position the ball in the hole so that the top of the root ball will be about 10 percent above the finished soil grade. Make sure the tree is straight and start to backfill the original soil until the hole is about half way full. Do not add fertilizer or soil amendments. This, too, is hard advice to follow, but amending the soil only creates a “clay pot” beyond which, in the years to come, neither roots nor water will extend. If you are preparing an entire bed, then amending the soil throughout the bed with organic matter (not peat moss) will improve soil health; but if you can only work with a planting hole, leave the amendments behind.
- Now water, tamp in the soil firmly around the tree roots and make sure the tree is still straight and will end up at the proper grade. Fill in the hole the rest of the way. When you are finished, there should be no landscape soil on top of the root ball. Apply a 3-inch-thick layer of mulch around the plant to discourage weeds but limit your mulching to the outer edges of the hole and beyond; do not mulch the root ball itself. Do not apply landscape fabric.
- Most plants less than 6 feet tall with less than a 1-inch trunk do not need to be staked. Scientists have discovered that a little swaying in the wind strengthens the trunk. There are some clever new ways of staking a tree with a root ball that do not run the risk of girdling the trunk caused by traditional methods. See North Carolina Agricultural Extension’s advice and the University of Florida’s Cooperative Extension Service method.
- Once planted, your new tree will need regular watering through its first year to fully establish a root system in the landscape soil. Most trees do not get enough or regular water during this period.
Tom Watson is a Volunteer Extension Master Gardener in Mecklenburg County. He has also received a Certificate in Native Plants from UNC-C and a Certificate in Horticulture Technology--Residential Landscape Design from CPCC. He and his wife, Sue Bartlett, own The Cedars Davidson Bed & Breakfast.