These two books were written by Linda Chalker-Scott, former urban horticulture extension specialist and a professor in the Department of Horticulture at Washington State University.

They say you can’t judge a book by its cover – or its title, for that matter. It was by chance that I read “The Informed Gardener – Blooms Again,” a book full of examples of horticultural myths, misconceptions and pseudoscience, most of which are still in practice today. Judging by the book title and cover picture, I would have thought the book was written specifically for avid gardeners. Guess what? Arborists, nursery workers and landscapers, this book is for you!

Over her decades-long career as a research scientist, Chalker-Scott has dispelled dozens of myths with science and research. Most book reviews, in general, are of recently published books. “The Informed Gardener” and “The Informed Gardener – Blooms Again” were published some 15 years ago, but their relevance is just as applicable today.

I find her writing style and format unique and refreshing. She makes learning easy and always explains the “whys” in her answers. Each of the Myths covered in the two books begins with the myth printed in italics and then explained. She then covers The Reality of the situation and ends with several Bottom Line bullet points. Of course, all references are listed, and the information comes from peer-reviewed journals and publications.

The books are quick reads. Each myth explained is like a chapter and is only several pages long. I found myself drawn in and hooked. You don’t have to read the book from start to finish. It’s easy to jump around to and from topics that interest you the most. Some examples of what I learned in these two books follow.

The myth: If a plant develops red leaves, it means phosphorus is deficient. The reality is, the red color comes from the anthocyanins that are produced and that accumulate in the foliage. There is no single reason why leaves turn red, and many of the other reasons are given. Some are genetic. On the other hand, high levels of phosphorus inhibit both trace-mineral-element uptake and mycorrhizal establishment. This is a consideration when diagnosing and treating interveinal chlorosis.

It is a myth that tree-wound dressings protect wounds from insects and disease. (The exception is in the prevention of the spread of oak wilt or Dutch elm disease). The reality is, oxygen stimulates the compartmentalization of decay in trees (CODIT) when a tree is wounded. Tree-wound dressings prevent adequate oxygen from reaching the damaged cells and will inhibit callous tissue and wound-wood formation.

There is the myth that vitamin B1 reduces transplant shock by stimulating root growth. B1 is frequently found in products containing auxin. Auxin does reduce transplant shock, but not vitamin B1 on its own. Growth restoration by mineral elements is interpreted by some as growth stimulation.

It is a myth that glyphosate will systemically spread or translocate from one plant to another. The reality is that translocatable herbicides move systemically within a plant, but do not cross root grafts in healthy trees and woody ornamentals. Fungal vectors can cross root grafts through enzymatic activity, which non-living herbicides do not produce.

Conclusion
These two books are invaluable resources for the serious arborist. I could go on and on with examples of the things I learned or that now make better sense to me. I’m excited to begin reading another of her books titled “How Plants Work.” All three paperback books are available on Amazon for less than $45. An amazing value.

Steven F. Pregler is an ISA Certified Arborist and retired city forester for the city of Dubuque, Iowa.