How to successfully transplant your trees and shrubs?

When to transplant a shrub or young tree?

Ideally, transplanting of trees and shrubs is carried out between October and March, during dormancy but not during periods of frost.

Required equipment

• spade: to dig up and cut through roots
• disinfected pruning shear: to prune branches and small roots
• watering can or garden hose
• good-quality potting compost
• horn meal (or other root amendment)
• mulch (dry grass clippings, RCW, buckwheat hulls…)

How to transplant a young tree or shrub?

Younger trees are easier and quicker to transplant. Older trees require more planning.

Transplanting a young tree or shrub: “express” method

For young or small specimens, a professional technique is not always necessary. However, follow these steps to give the plant the best chance of success:

First step: preparation

1. Water thoroughly the day before transplanting all around the specimen to hydrate the roots and loosen the soil.
2. Prepare the new planting hole, sized to suit the specimen being moved — at least as deep and 1.5 times as wide as the rootball — and pour the equivalent of a watering can into the bottom.
3. Reduce the plant’s foliage by pruning moderately with a disinfected pruning shear. Remove dead wood, crossing branches or those growing inward. If you must cut branches 5 cm diameter or larger, disinfect the wound with a suitable product.

Second step: transplanting

1. Cut all around the tree or shrub with a spade or trenching spade (narrower and longer) very sharp, to at least 50 cm depth. The aim is to sever peripheral roots. Work about 50 cm from the trunk to form a circle 1 metre in diameter.
2. If large roots resist, cut them cleanly with a pruning shear or lopper.
3. Leverage with your spade or trenching spade, gradually working around the plant. The aim is to recover as much root and soil as possible.
4. Once lifted, replant immediately at the new location after adding horn meal to the bottom of the hole. Ensure the collar (junction between roots and trunk) is level with the soil.
5. Backfill with good-quality compost mixed with your soil and form a watering basin at the outer edge of the rootball.
6. Firm down and water thoroughly to remove air pockets.
7. Mulch (dry grass clippings, RCW, buckwheat hulls…).

After transplanting:

• Monitor soil moisture: it must not dry out in the weeks following transplanting,
• If a stake is needed, place it on the side of prevailing winds, before or at the same time as the plant.

Transplanting a Cestrum

Note:

• For large specimens, it is best to call a professional who masters the technique and has appropriate equipment.
• Trees and shrubs that prefer heather soil (camellias, rhododendrons…) develop a shallower root system and tolerate transplanting better, even when they are more mature and larger.

Transplanting an older tree or shrub: root-pruning, the professional method

To better prepare a large specimen for relocation, nurserymen use the “cernage” technique. This operation is carried out about one year before transplanting.

1. As with the ‘express’ method, water the day before the operation and cut cleanly all around the tree or shrub.
2. Make a second circle outside the first, about one spade-width wider.
3. Then cut down into this ring perpendicular to the surface, and remove soil to a depth of 50 cm.
4. In the trench thus created, mix the excavated soil with rich compost and sand to obtain a light substrate in which new roots can develop.
5. Water thoroughly, and do not let the soil dry out in the following weeks.
6. One year later, transplant the specimen.

Some special cases

Moving a large tree or shrub is a risky operation often requiring a professional and techniques such as root pruning carried out a year in advance. This frequently concerns magnolias, Japanese maples that are mature, or other high-value landscape specimens such as conifers.

In contrast, ericaceous plants (such as rhododendrons, azaleas and camellias) are easier to transplant, even when fairly large, thanks to their shallow, compact root system. The essential point is to reproduce their acidic soil conditions in the new location to ensure success.

Hydrangeas also have a relatively shallow root system which makes them much more tolerant of this operation than other shrubs. To maximise chances of recovery, move them ideally between October and March, outside periods of frost.

Good to know: generally, trees and shrubs that develop a deep taproot are very difficult, if not impossible, to transplant once established, because this main root is too sensitive to cutting. This is the case for many oaks, beeches, walnut trees and some conifers at maturity.

Young shrubs are much easier to move than older specimens.

Post-transplant care tips for successful establishment

After moving your tree or shrub, regular deep watering is crucial to help its roots recover, taking care never to let the soil dry out completely.

If necessary, install a sturdy stake on the windward side to stabilise the plant and protect young roots from movement.

A thick layer of mulch at the base of the plant will retain moisture, regulate soil temperature and reduce competition from weeds.

Finally, monitor closely for any signs of stress and avoid over-fertilising during the first year to prevent burning roots.