Christie’s Blog

Late August 2024

Planting Trees this Fall

A Round Peg in a Square Hole

As fall approaches so does the best time to plant trees or shrubs. I wanted to review the new, somewhat controversial task of what shape to dig the hole for a new tree.

When planting in round holes there is a tendency for roots to grow in a circle. The new weaker roots easily follow the softer soil added to the hole when the tree is planted. Roots go around and around in a circle squeezing the root ball. Trees “girdle” and eventually strangle themselves.

The solution some believe is to dig a square or rectangle hole. Roots have a longer distance to grow away from the root ball. They have time to strengthen before they hit the obstruction of more dense soil. Girdling is avoided.

If you see roots on top of the ground like the picture below, you have girdling of the tree. It is important that the roots crossing over the root ball are cutoff for the tree to thrive. If the root is over 2” thick you should consult an arborist because it may be a support root for the tree.

I have read it is harder to dig a square hole but if it helps your new, no doubt expensive tree to live, I think most of us can handle it or grab an unsuspecting youthful relative to assist.  Take a few days to dig if you have to. The tree appreciates it!

Christie lives in Manakin Sabot , Virginia where she manages a 3 acre garden. Her blogs are written from her 35 years as a personal and professional gardener.