Prepping a shrub rootball for spring moving

(Question)

Hi. I have two medium/large honeysuckles and a very large mugo pine that I’d like to dig up and relocate. I’d heard that it’s best to cut down into the roots at the canopy drip line in the fall… then leave the plants alone over the winter and move them before they “come to” in the spring. This way the plants roots can recover to a degree before winter and not be too shocked when moved in the spring.
My questions are:
1) Is this true?
2) If this is true, can I do this now or do I have to wait until, in the case of the honeysuckles, they drop their leaves and are more dormant?
Love to know your thoughts.
Thanks. – A

(Answer)

Great question.

You can reduce “transplant shock” by root pruning trees and shrubs in advance of actually moving them.  The period of time in advance between the root prune and the move can be as short as a few months season or a year or more in advance depending on the type and size of the plant and how long you are willing to wait. Root pruning allows the plant to develop new smaller feeding roots on the remaining roots which should enable it to become more quickly established in the new location and enhance its survival after the move. Transplanting deciduous plants, such as your honeysuckles (which I assume are shrubs and not vines), should be done when the tree or shrub is dormant – i.e. late autumn after the leaves have fallen but the ground is not yet frozen, or late winter/early spring when the ground can be worked but the buds have not yet broken.  While the the optimal time for transplanting some plants is late fall (in which case you would root prune next spring and actually move the plants late next fall) honeysuckles and mugo pines are both quite hardy, forgiving and easy to transplant so you should be able to root prune this fall and do the actual moves in the early spring as soon as the ground can be worked.  In the case of your honeysuckles, wait until until the plants are dormant, i.e have lost their leaves – as the root pruning is going to have an impact on the nutrients received by the plant and you do not want it to be actively growing.  You should also cut back the honeysuckles at the same time that you do the root pruning as the plants will have less roots to support their healthy growth. In the case of the mugo pine, you can do the root pruning right away as you want to give the plant a change to develop new feeder roots before the ground freezes. It is not necessary to cut back the mugo pine at the time you do the root pruning, although you might want to prune it in the late winter/early spring depending on the shape of the plant.

Here is a link to previous Toronto Master Gardener answer to a question about transplanting a mature shrub: https://www.torontomastergardeners.ca/askagardener/transplanting-a-mature-anthony-waterer-spirea/

and a piece published by Penn State Extension: Transplanting or moving shrubs

which contains fulsome discussions of issues to be considered when transplanting trees and shrubs.

Sept. 25, 2022