A buddy of mine, Alison O’Connor, is a graduate student at Colorado State University. She’s working on her Phd. in horticulture, and as part of her research, she had to plant 27 trees today. Playing in the mud is always preferable to pushing paper on a desk, so a bunch of us went over to give her a hand.
The trees needed to be planted as correctly as possible, and Alison offered us a refresher on proper planting techniques. Planted too low or to high, and the tree suffers, unable to root out to support the 100-year lifespan.
If you’re popping a tree into the ground this fall, brush up your skills by following her step by step advice:
Measure the height of the root ball to determine depth of planting hole, which should be one to two- inches shorter than the root ball.
Dig saucer-shaped planting hole, three-times the root ball width. Straight sides limit root expansion, so to get your tree off to a fast start, slope the sides of the hole. We had straigh holes dug with an augur, then sloped the sides with a shovel.
Remove tree from container, clip any girdling roots, score the rootball, then set tree in place. The “knees” of the rootball – the top edge of the soil – must be about two inches above the planting hole.
If your tree has a “dogleg” from grafting (a curve in the trunk just above the graft), turn the rootball so the inside curve faces north. This helps that sensitive spot avoid sunscald.
Pack soil around lower third of rootball, to help stabilize it. then backfill the rest of the hole, leaving soil loose.
Water the planting area.
Mulch the tree.