“Fall Is Great, But March Is Better” – Transplanting

by Pat Diaz, from the September 2003 Newsletter

Are you contemplating, with great trepidation, the transplanting of trees or shrubs this year or next? Transplanting is a serious move by gardeners and it’s necessary to prepare ahead in order for things to go smoothly and for your trees or shrubs to thrive.

I recently had a wonderful chat with Roger Blanchard, Moscow parks’ arborist. He has some excellent tips for transplanters.

He told me that while fall was a great time to transplant, here on the Palouse, March is better. Fall is tricky in case there’s an early freeze, not enough rain, etc. But shrubs and trees are putting on root growth, leaf drop has started, the soil is cooler and hopefully the rains have started. Usually, Roger said, the first week of October is the best window of opportunity. You must ensure that your plant has enough moisture, so water heavily several days before you transplant. His favorite transplant time, however, is March when the ground is soft, there is plenty of moisture in the soil, and, most importantly, growth has not started. You can bare-root your shrubs/trees and, when digging, get more of the root system.

So how is it done? First, decide what to transplant and then check out the place where you want your plant moved. You do not want to amend the soil; keep the plant’s “home environment” the same. Mark the side of your tree/shrub that is oriented to the sun, as you want the same orientation after you’ve moved it. Dig the new hole but not too deep; make it the depth of the current root system and at least two times wider. Roger said that planting too deep is a big killer. A hole too deep creates a perfect place for water to settle, and this will rot out the roots. And on the Palouse, our heavy clay soil can often create a compacted “pot” around your tree. So with your shovel, whack the sides of the hole to rough things up and give the roots places where they can penetrate the clay. Roger also said to plant your tree with about one-third of it above the soil and then mound soil around it. This, too, will help alleviate root rot from settling water.

When you dig your tree/shrub up, make sure you dig deep enough and wide enough around it to get the maximum amount of the root system. If the tree is large, you may have to prune the roots with a sharp shovel. With large trees, make sure the soil is attached, especially in the fall. Most shrubs require a root ball-diameter of approximately two-thirds of the branch spread. Digging a hole sufficiently wide and deep will ensure that you can make your undercut below the roots. Also make sure that all roots are severed before you try to lift the tree. Rough up the soil ball on the outside to eliminate that compacted “pot” effect.

Move the tree/shrub to its new home as soon as possible so the roots don’t dry out. If you’re transporting the tree via vehicle, protect it from drying winds with damp burlap, a box, etc. Pre-water your hole and re-check to make sure the hole is two-to-three times wider than the root ball.

Water the plant immediately after you complete the transplanting. Monitor it regularly to keep the soil from drying out if there isn’t sufficient rainfall. You can also mulch around your tree/shrub to conserve moisture and moderate soil temperature. Newly transplanted trees and shrubs probably won’t need fertilizer for the first few years, as they will be obtaining nutrients naturally occurring in the soil.

Pruning may be required before you move your tree. If there are any broken stems, remove those. If there are low branches, you may want to tie those up to prevent damage during the move. Otherwise, hold off on pruning for at least one year after transplanting.

There is a lot of information on the Web if you want to learn more, and you can call our local university extension offices. You might want to check the transplant tolerance of tree/shrub species, too, before you start. Good luck!

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