September 26, 2001
TRANSPLANTING ORNAMENTAL TREES AND SHRUBS
By Gary W. Hickman, Horticulture Advisor
University of California Cooperative Extension, Mariposa County
If you need to move an ornamental plant, remember that more is involved than just digging up and planting again. Successful transplanting involves a knowledge of what, when, where, and how. With a few pointers, however, the home gardener can insure a healthy plant in its new location.
Whether you are moving a tree or shrub because it is too crowded, gets too much or too little shade, or simply because it would look better someplace else, successful transplanting can depend on the condition of the individual plant. Young and healthy plants are more likely to survive the shock of transplanting than older or unhealthy ones. Very old, damaged, or diseased plants should not be moved.
The best time for transplanting is when plants have become dormant in the fall or are still dormant in early spring. Actually, anytime after the leaves fall and before buds start to grow is acceptable. Evergreen plants can generally be transplanted any time other than the middle of the hot summer.
In choosing a new location, select a planting site that will not only look good, but also consider sun, shade, and wind exposure.
To dig up a tree or shrub, it is most important to avoid injuring any roots, if possible. Also, if the trunk diameter is greater than three inches, the plant should be moved with a root ball. The larger the ball, the greater chance of success you will have in transplanting. In general, go out one foot from the trunk in each direction for each inch of trunk diameter. You should also know that dogwoods, magnolias, oaks, and maples are considered difficult to transplant.
Before planting the tree or shrub, make sure that the planting hole is wide and at the proper depth. A hole at least twice the width of the root ball is required for good growth. The hole should only be deep enough so the plant can be set at the same level it was planted before.
Drainage in the new location is also very important. If it is poor, water will collect around the roots and cause them to rot. To test for drainage, dig a hole a foot deep or more and fill it with water. The next day fill the hole again. If the water remains in the hole more than 12 hours, you may want to consider another planting location.
After planting the tree or shrub, water it in well. The most important irrigation the tree will ever get is the one right after planting. This watering helps big soil particles come into direct contact with the roots. If not done, air pockets are left that can dry out and kill roots.
After transplanting, some references call for a major pruning “to balance root loss,” however, this is not usually necessary. Roots need leaves to provide energy for growth, so pruning branches after transplanting is actually counter productive to good establishment.
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