When transplanting trees or shrubs from one location to another, digging the plant in preparation for moving it is typically the most challenging part of the job.
Anyone who grows trees and shrubs is likely at times to wish to move them. Transplanting involves digging the tree or shrub, moving it to its new location, and then replanting it. The most difficult of these steps, and the one which requires the most know-how, is digging. This article discusses digging up trees and shrubs to about 10 cm (4”) in trunk diameter.
For small plants – up to a trunk diameter of 2.5 cm (1”) or so – digging can be done with an ordinary garden spade. It is important to do it right, but the work is not difficult and the odds of success are very good. For trees or shrubs with a trunk diameter over 2.5 cm (1”) in diameter, and up to as much as about 10 cm (4”) in diameter, there are good options available which make it possible for even the home gardener to transplant successfully. Note, however, that size and weight of the required root ball, and the work involved in transplanting, increases rapidly as the trunk diameter increases. Moving trees with trunks over about 10 cm (4”) in diameter is likely to require heavy equipment and specialized expertise. The cost of transplanting increases rapidly as the size of the tree increases, although there is almost no limit to the size of trees which can be transplanted successfully if one is willing to pay the price.
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Digging a tree or shrub in preparation for transplanting involves several steps. Various digging techniques can be employed, but no matter what approach is used, these steps must be attended to. The information covered here includes just the bare essentials. There are many factors which should be taken into account if one is to realize the best possible results. These considerations include the species of plant being moved and its condition, the soil conditions, climate, season of the year, and accessibility of the site.
This stabilizes the root ball to help ensure that it stays intact during the transplanting process and is usually done B&B style (ball and burlap) or in a "WB" wire basket.
Depending on the digging method used, steps 3 and 4 may be reversed.
A fast handdigger can dig 20-20 16" root balls an hour or better. A machine spade can do 30-45 an hour. The bigger the ball the more time it takes to handle the tree properly.
There are several related new tree moving/growing techniques worth mentioning:
Dr. Bonnie Appleton Phd has been experimenting at Virginia Tech's Hampton Roads Virginia Research Station with a method that water washes the soil from the roots thus barerooting trees at any time of the year in order to examine and prune the roots for defects, (a major problem caused by the improper planting of young trees) then she washes the soil back around the roots with water to create a mud backfill whick locks the tree into the ground and eliminates air pockets in the soil. This also supplies the tree with a large influx of moisture to quickly grow new feeder roots.
Ren Heard of Lake Tree Farm in Virginia and Kentucky, uses a similar washing technique using a 750 psi orchard sprayer, combined with growing the recently dug tree in custom made baskets made of wood snow or sand fencing with more closely spaced pickets (organic pots) that air root prune the tree, eliminating circling roots (a major problem of pot growing), tap roots and wind roots are minimized, with a large increase of feeder roots thus allowing the tree to be replanted at anytime of the year with no transplant shock. This method is called Organic potting.
Approximate root ball diameter to be dug
trunk diameter | multiplier |
---|---|
up to 1.3 cm | 20 |
1.3 to 2.5 cm | 18 |
2.5 to 3.8 cm | 16 |
3.8 to 6.4 cm | 14 |
6.4 to 10 cm | 12 |
Approximate root ball depth
root ball diameter | root ball depth |
---|---|
30 cm | 20 cm |
120 cm | 45 cm |
When transplanting any plant, preserving a significant fraction of the root system is necessary to maximize the chances of successfully re-establishing the plant in its new location. The practice of root pruning in preparation for transplanting can help concentrate the root system into a more confined area, thereby increasing the fraction of the root system that can be preserved.
In the case of trees and shrubs, the weight of a large root ball, and secondarily the weight of the tree itself, contribute significantly to the effort required to dig and move the plant.
Trees and shrubs of all sizes may be dug up using simple shovels.
Conventional earth moving equipment such as backhoes and front loaders are also used.
Some nurseries use tree spades,[1] which are specialized powered equipment dedicated to digging up trees and shrubs.
A specialized tool for cutting roots may also be used, possibly in conjunction with a leverage-based manual system for lifting the root ball.[2]
In the case of extremely large trees, these have at times been moved by equipment designed for moving missiles.