The shortened life of rootbound plants

By Mary Fran McClure
WSU Chelan/Douglas County Master Gardener

Roots girdling a dead tree.
The demise of this little pine tree is quite obvious from this mass of encircling roots. Similar problems can be avoided if you take care while planting new trees, shrubs and plants this spring, says WSU Master Gardener Mary Fran McClure. – Provided photo/Mary Fran McClure
Mary Fran McClure
Mary Fran McClure – WSU Extension Chelan/Douglas County Master Gardener – photo by Don Seabrook, Wenatchee World

Strangler fig trees in the tropics own that name for good reason. Little sprouts cling to established trees and grow upward, seeking sunlight. They are fast-growing, and, before many seasons, those fig trees are squeezing out their host, eventually killing it. By then the fig can stand on its own.

A similar phenomenon happens underground when we plant a rootbound tree or shrub without opening or cutting encircling roots. The transplant will thrive for a few years and then begin to decline. Aboveground, we see no reason for that decline, although digging up the plant will uncover the sad story of strangled roots.At my previous home, some nice, small-scale trees had been planted by the previous homeowner. They looked nice for a few years. Then I noticed they were looking stunted and unhealthy. A little digging around them uncovered the problem of strangled roots. Next step: removal.

There is a moral to this story. When buying new plants, especially trees, shrubs and even perennials, dislodge them from of their containers and take a look at those root systems. Take a hori hori knife, pruner, or weeder (depending on root diameters) and open that mass of roots. Larger roots might require sawing if they are encircling the pot. Yes, it’s a shame to cut them, but that is less harmful to the plant.

Healthy roots radiating out from the plant gives it more stability and better ability to withstand winds. And a larger growing area provides more soil area to pull in water and nutrients.

As for transplanting depth, it’s better to plant slightly higher rather than lower. Look at the plant’s root collar flare or soil line in the container. Sometimes container plants are not planted at the proper soil line, so don’t just automatically redo a problem. Take a good look at where the collar flair is on each plant and plant accordingly.

For an existing shrub or tree showing an obvious girdling root at its base, take a saw or pruners and cut it, lessening the restriction. I have a coarse-bladed root saw for just such operations.

Bare-root plants should be inspected for the dreaded J-root problem. That means a confined root that turns upward, forming a “J” shape. If you can’t reject the plant and choose one with a better root system, then cut off that problem root and let the healthy roots take over.

Early spring is a great time for adding trees, shrubs and perennials. Examine root structures carefully before planting and spread out any encircling roots or other problems. Your plants will be healthier and more vigorous, and you will be richly rewarded.