Tree, shrub transplants:Mixing art and science

October is one of my favorite months because, in my opinion, it is the best month for transplanting evergreen trees and shrubs. There is something immensely satisfying about digging up and successfully moving a large rhododendron or viburnum to a location where it will be better appreciated or stand a better chance of survival.

Through the years I have looked at various ways of reducing what is known to gardeners as "transplant shock" — not just in the process of digging and moving — but through products that can alleviate the stresses of relocating plants around the landscape.

Transplant shock refers to the cumulative effect of root loss incurred during digging and the possible compounding of stress caused by improper handling and care during this time. Allowing the root ends to dry during the moving stage or improper planting-hole preparation are examples of stresses that can shock a plant. The cool, moist weather of October is perfect for helping to keep roots moist while lessening the amount of water needed by the plant. It is certainly a huge factor in a successful transplant.

For years we have heard about the beneficial effects of using products containing vitamin B-1 when transplanting. The following is a claim taken from the Web site of a nationally known and respected company: "(X-brand)® Vitamin B-1 Plus stimulates the quick formation of new root hairs and revitalizes the delicate feeder roots that are often damaged in transplanting. (X-brand)® Vitamin B-1 Plus is especially designed to hasten the development of bare-root roses, shrubs, shade trees and bedding plants that have been moved to new locations. It helps plants become established quickly and ensures vigorous growth." Great. Then I definitely need to get some and use it anytime I transplant, right? Well, not so fast.

Linda Chalker-Scott, Ph.D., Extension horticulturist and associate professor at the Puyallup Research and Extension Center of Washington State University, has this to say regarding the use of Vitamin B-1: "Applying vitamin B-1, or thiamine, to root systems of whole plants does not stimulate root growth. This is a myth that refuses to die, though it has been repeatedly refuted in the scientific literature.

"Vitamin B-1 (thiamine) is an important component of tissue culture media, in which isolated plant tissues can be propagated," says Chalker-Scott. "Its use for stimulating root growth in whole plants is not supported in the literature and one study reported that root growth was greater in the control treatment (water) than with thiamine.

"Plants in the field manufacture their own source of thiamine and it is therefore unnecessary to add any additional levels," Chalker-Scott adds. "Many fungi and bacteria associated with plant roots also produce thiamine, so it's likely that healthy soils will contain adequate levels of this vitamin without amendment."

With this conflicting testimony, whom is the gardener supposed to believe? For my part, I tend to side with the scientists. If something is true, then it is repeatable, which is the scientific method.

Dr. Chalker-Scott goes on to say, "A nitrogen fertilizer is adequate for transplanting landscape plants; avoid use of "transplant fertilizers" that contain phosphate."

What's this? No phosphorus? Is bonemeal out the window? Use nitrogen when transplanting? That's heresy! It goes against the grain of gardening's common knowledge.

The point is this: in the world of gardening, you're likely to find conflicting advice on everything from transplanting to feeding your lawn. Whose advice you trust and use will follow your general philosophy of life. Whether you believe in the principles of feng shui gardening or planting by the phases of the moon, if you have repeatable success with one method or another, use it. That, after all, is all the proof you should need. Gardening is as much art and magic as it is science and technology, and what brings results is the important thing.

October is my month for transplanting evergreens, but if you wait until January does that make you wrong? Only if your transplants struggle and fail to take hold. Gardening practices generally afford a lot of latitude — enough room to make hard-and-fast rules unnecessary. But when I want to move a big camellia, I'll still take October!

Stan Mapolski, aka The Rogue Gardener, can be heard from 9-10 a.m. Saturday mornings on KMED 1440 AM and seen in periodic gardening segments for KTVL Channel 10 News. Reach him at

Share This Story