How to Transplant Shrubs in the Fall
Roger Cook covers the pros of tackling the task during the chilly season
Is it okay to transplant a shrub in the fall? I’m worried that the shock of being moved will hurt its chances of surviving our frigid winters. —Deb Madigan, Green Bay, WI
Fall is a great time to transplant shrubs. The days and nights are cooler, so the soil doesn’t dry out as fast as it does in the summer. The air temperature may be chilly, but the ground is still warm, which encourages root growth late in the season. I also find it much more comfortable to do all the necessary digging and lifting when the weather isn’t so hot and sticky.
Whenever you relocate a plant, the goal is to minimize the shock of the move by keeping as many roots intact as possible. Here are the rules I follow to ensure a successful transplant.
First, you need to define the root ball diameter. To do that, multiply the trunk diameter by 10. For example, a shrub with a 2-inch trunk should have a 20-inch root ball. Stretch a loop of string equal to the radius of the root ball around the trunk, and use a stick at the other end to mark the perimeter of the ball. Use a spade to slice through the roots vertically along the circle. Turn the spade backward; that makes it easier to keep the blade straight up and down.
Once you’ve severed the roots, dig a trench about a foot wide and 12 to 18 inches deep outside the perimeter, then work under the ball until it’s free of the surrounding soil. Take care not to rock the plant or otherwise disturb the roots in the process.
Now, in the shrub’s new location, excavate a straight-sided hole twice the diameter of the ball and 2 inches shallower than its depth. You want the top of the root ball a bit higher than the surrounding grade so that the roots aren’t buried too deep.
If the ball isn’t too big and unwieldy, you might be able to slip a tarp under it and drag the shrub to its new spot. Otherwise, wrap the ball tightly in burlap and twine and carry it to the hole in a hand cart or wheelbarrow. Fill around the ball up to grade, then water thoroughly and cover with 2 inches of mulch. Don’t stamp on the backfill; roots can’t grow well in compacted soil.
Water your shrub regularly until the first frost. The better it’s hydrated before winter, the better its chances of getting off to a good start come spring.