The University of Tennessee publication SP572 Transplanting Trees states, “Water stress is the primary cause of transplant failure.” To learn more about transplanting trees get this brochure at your county UT Extension office or download it from the website www.utextension.utk.edu/publications/homeGarden/.
A recent reader inquiry spotlights problems that can develop when newly planted tree roots get too much water. Description of evergreen transplant troubles: After Thanksgiving (2009) a Crossville couple had five 8-foot Leyland cypress trees planted. At transplant time, the ground was already soggy. (It was unusually rainy in Tennessee last fall.) More rain poured down while the trees were being put in. For days afterward there were strong winds. The trees fell over and had to be staked twice to keep them upright. As freezing weather came early and persisted throughout winter, the homeowners feared the cold might also have harmed the transplants. Foliage on the street side changed color. Needles along branch tops stayed green but those on the undersides turned brown. This spring they fertilized with 10/10/10 fertilizer as directed on the bag. Judging by appearances fertilizing did not help. By April when the email was sent, the Leyland cypress trees were looking worse each day.
The question: "Have the trees been stressed so much that we’re going to lose them? Is there anything else that might be done or could we call anyone to help prevent the death of these beautiful (and very expensive) trees?"
Response: Browning foliage can be a sign of root damage. In saturated earth there isn’t enough oxygen for plant roots. Roots starved for oxygen get damaged, work inefficiently and may develop root rot disease. Rain during transplanting isn’t usually bad but contributes more water which displaces oxygen normally found in soil air pockets around plant roots. When the trees fell over and had to be staked repeatedly there was lots of foot traffic which packed wet ground around the trees down (squeezing even more oxygen from the soil). Under the circumstances described, I would look at the roots before trying any remedies. (Unfortunately, fertilizing may have been the kiss of death as plant food stimulates growth which stresses a plant with root problems more.) Dig around a tree with discolored foliage to inspect the roots. Black or slimy roots indicate root rot. Root rot usually kills the plant.
On the other hand, firm looking, creamy-colored or white roots are a sign of health. If the roots look good, cut a branch with both green and brown needles. Bag the sample and take it to the Cumberland County UT Extension office in Crossville. The agriculture agent or Master Gardeners working in the office will examine your sample for signs of disease or insect pests. Once a diagnosis is made they can recommend appropriate treatment.
If the trees do have root rot and can’t be saved, put in good quality trees that are smaller next time. A healthy tree is a more likely outcome with a smaller specimen. Woody transplant roots don’t grow very quickly and lots of roots are needed to support the top growth on an 8-foot evergreen. Younger Leyland Cypress can make up the height difference in a few years time. Autumn transplanting is best because all the plant’s energy goes to establishing roots. Energy is diverted to new foliage growth in springtime. Roots anchor a tree. A bigger evergreen has more foliage to catch the wind. Before roots get established risk of a large transplant falling over in gusty winds is high. Repeated toppling can injure branches.
Plateau Gardening is written by Master Gardeners for those tending home landscapes and gardens in Tennessee’s Upper Cumberland Region. UT Extension Cumberland County at P.O. Box 483, Crossville, TN 38557 (484-6743) has answers for horticulture questions, free publications and details on how to become a Master Gardener. Send email comments or yard and garden inquiries to Master Gardener Rae, firstname.lastname@example.org.