Issue: August 18
Transplanting New Mexico locust and Russian olive and what to do with a tree the wind broke
Q. Please tell me how to transplant runners from a New Mexico locust and a Russian olive tree? Also, the wind broke a New Mexico locust with a trunk about 4-5 inches across broke (completely) where all the branches emerged from the trunk. It is still growing like crazy. How far up the trunk should I strip off the new growth? Or should I? It was about 25 feet high. I planted it in this spot about a year ago. It was purchased from a nursery.
Cedar Crest, NM
A. I think you are asking about transplanting "suckers" produced by roots of the New Mexico locust and the Russian olive. You called them runners, implying they formed some distance from the parent plant. It is important that I understood correctly, because the source of the new growth makes a difference in success when trying to start a new plant. The botanical definition of a sucker (what I think you are calling a "runner") is a sprout from an adventitious bud produced on a root. These new sprouts will form their own root system, but they are connected to an existing root. Some people, when referring to "suckers" mean sprouts that form from the base of a stem (properly called offsets). In some plants, these offsets can be induced to form roots, but may not have roots initially. Other people when referring to suckers, are actually talking about watersprouts, rapidly growing shoots produced from branches. These are more difficult to induce to form new roots and grow new plants.
If you are referring to the true suckers, produced from buds on roots, then it is a fairly easy matter to transplant the new plant. If you are referring to a sprout from the base of the trunk, you may be able to cut it from the parent, treat it with rooting hormone, and with proper treatment induce rooting. The watersprout will also require rooting hormones to induce rooting. I will discuss transplanting a true sucker that initiated from a root.
Suckers can be dug up with some of the "mother" root and transplanted in the fall as the tree becomes dormant or in the late winter before growth begins (once the soil has thawed and digging is possible). Smaller suckers may transplant most easily, but because they have less food reserves in their stems, should be transplanted in the late winter. Larger (but not too large) suckers can be transplanted in the fall. With greater stored food in their stems, they can begin some root growth in the fall. (Many trees produce roots in the fall when the air has cooled and the top ceased growth, but while the soil is still warm.) The trees you want to transplant are fairly tolerant of transplanting and should transplant successfully.
Is the wind-damaged tree really a New Mexico locust? The size you mentioned causes me to wonder if it is an Idaho locust or other species with pink flowers. That makes a slight difference, but may not be critical. If I understood correctly, the trunk broke below all the branches, but there are sprouts coming from the trunk below the point of the break. These are the sprouts that will allow you to salvage the tree. The point of the break has allowed decay organisms into the trunk and can, in time cause the tree to die or break again. If the tree is near a house, structure, or place frequently occupied by people, it may be wise to replace the tree. However, if it is in a safe location, you can choose one of the highest sprouts on the trunk to become the new "leader" (central trunk). Other branches can be allowed to remain for a few years to help feed the growth of the trunk's diameter, but prune these back from the tip each year to discourage them from developing into competing leaders. After 2 to 3 years you can remove them at the trunk. By then, the new leader will have developed and should have branches forming. Prune so that the branches are spaced several inches apart and spiral around the trunk. It is not good if all the branches are produced from the same point on the trunk. The New Mexico locust has a tendency to produce multiple trunks and grow more as a large shrub than a tree. You can remove the competing trunks, or encourage growth as a shrub.
For more gardening information, visit the NMSU Extension publications World Wide Web site at http://aces.nmsu.edu/pubs/_h.
Send your gardening questions to:
Yard and Garden, Attn: Dr. Curtis Smith
NMSU Agricultural Science Center
1036 Miller Rd. SW
Los Lunas, NM 87031
Curtis W. Smith, Ph.D., is an Extension Horticulture Specialist with New Mexico State University's Cooperative Extension Service. NMSU and the U.S. Department of Agriculture cooperating.