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How to Become an Afghan Bazaar Queen
Debunking the Myths of Bonsai
BONSAI Past and Present
Dealing with Difficult Roots
Escapees! Get em!

Name: #3 / Will Heath
Country: USA
Credits: See References
Category: Non-Fiction
Submission Date: 04/24/2008

Debunking the Myths of Bonsai


There are many myths in bonsai ranging from the common belief among the dilettante that "bonsai" is a certain species of tree, to the belief that trees are starved and tortured in order to become bonsai. It is not my intention with this article to dive into myths that the uninitiated believe, but instead to address the myths prevalent with practicing bonsaists themselves.

Debates on the effectiveness of certain products, techniques, and methods have raged for years, with each side listing out personal experiences, information read elsewhere, words of the experienced, or quoting friends of friends who heard from some master somewhere. However, few people have actually conducted controlled experiments to determine the validity of such claims, fewer still have actually went outside of the bonsai community and sought out the truth from experienced researchers, horticulturists, or biologists.

Many people seem determined to believe that we can improve on what evolution has produced in the growth and healing aspects of plants. They seem to suspend belief to the point of going against logic and common sense in their determination to accept, at face value, the wildest claims based upon old, outdated research from decades ago, research that has long since been debunked.

Maybe there is a subconscious need for a potion that will create a shortcut or mystify the basic care requirements of bonsai. Yet, unfortunately, no magic brew or miracle mixtures exist yet, plants have the exact same needs and requirements they have had since they first evolved, light, air, water, and nutrients. These needs are all we need to meet in order to assure maximum health, as we style our trees into artistic visions.

Why some people feel that they, though unsubstantiated chemistry and science, can improve upon a plants natural responses to damage and stress is a mystery that may never be solved. Someday this may be the case, but that day is not now. Today, it is our responsibility to promote the truth and debunk the myths that prevail in bonsai.

Innovations do happen, rooting hormones, better fertilizers, and other such things have helped bonsaists all over the world. Innovations will come and, as a result, will change bonsai, as we know it. There is no reason to hang onto oldwife’s tales or to put faith in snake oils that have been shown to be ineffective. There is even less reason to support the manufacturers or sellers of such magic potions. A little research, a little common sense, and a little knowledge of how a tree grows will put these people out of business and let them know that bonsaists today demand state of the art products, based on sound scientific research, and which are supported by documented studies.

Below are some myths of bonsai that have been shown, without a doubt, to have absolutely no good effect at all when used on plants. Yet, the myths are prevalent throughout the community and to this day, you can still find advocates supporting the validity of the myths. I doubt that this article will change their minds, as after supporting the myths for so long, they have too much to lose. However, if this article prevents some from believing these myths or encourages a few people to rethink their beliefs based on the research quoted here, then it will be a success.

Maybe we can finally put these myths to rest, once and for all.

Foliar Feeding


Foliar feeding at first glance seems almost romantic; the thought of delivering nutrients directly to the foliage instead of though the soil, roots, and up the trunk to the foliage seems idea. The soluble fertilizer companies, seeing possibilities of increased sales, since foliar feeding uses far more of their product than traditional feeding practices, are quick to tout such claims as immediate results, prolong bloom times, increased pest and disease resistance, and even increased crop yields.

The problem is that most of these claims are based on some research done by Michigan State University in the 1950’s in which, by the use of raidolabeled nutrients, it was determined that the leaf is a very efficient organ for absorption. The amounts absorbed were actually very low but the efficiency was high, leading to false claims that foliar feeding was many times more effective than soil applications.

Linda Chalker-Scott, an Extension Horticulturist and Associate Professor at the Puyallup Research and Extension Center of Washington State University, clarifies this in her article, "The Myth of Foliar Feeding."

"Obviously, materials applied directly to a leaf are more likely to enter the leaf in large quantity than the same materials applied to soil. Leaching, chemical reactions, microbial activity, etc. can decrease what actually reaches the roots and is taken up into the plant. But material applied to the leaf do not necessarily travel throughout the entire plant as effectively as they do through root uptake. The often remain in the same or adjoining tissues but travel no further. This is especially true of those elements recognized as "immobile" within plant tissues (apart from root uptake and xylem transport)."

Linda goes on to state that the nutrients plants need the most of are the very ones that cannot be absorbed in large enough quantities by the leaf to do any good, such as nitrogen, phosphorus, and potassium. She also specifically states some facts based on research that may surprise many bonsaists, such as:

  • Tree and shrub species differ dramatically in their ability to absorb foliar fertilizers.
  • Micronutrients are the only minerals that can be effectively applied by foliar feeding and too much of these can damage or kill a plant.
  • Foliar spraying is only a temporary solution to the larger problem of soil nutrient availability.
  • Any benefit from foliar spraying of landscape trees or shrubs is minor considering the cost and labor required.

The common myth of foliar feeding is based on misreading and/or misinterpreting research done over 40 years ago. Since that time it has been shown that foliar feeding is ineffective in almost every aspect promoted by the companies that sell products designed for the practice. In fact, foliar feeding has been shown to work the best only in the case of soil with low nutrient availability, in other words, when a plant has no other option for nutrients. As bonsaists, our soil would never reach the level needed for foliar feeding to do any good.

Bonsai need nitrogen, phosphorus, and potassium the most, as do any other plants and these nutrients are the very ones that foliar feeding is the worst at providing.

It is my personal opinion that any success by bonsaists using foliar feeding can be directly attributed to the mixture running off onto the soil, not through absorption through the leaves. The common practice of watering from above and dosing the foliage puts the nutrients into the soil, even though the bonsaist believes they are foliar feeding.

Based on every single professional horticulturist statements on the subject that I could find, as well as studies from major universities, there is no other logical conclusion other than foliar feeding is ineffective, a waste of time, a waste of resources, and all claims to its validity are false.

The truth is that foliar feeding offers no advantages at all to the bonsaist.


Wound Sealant


Another popular myth is the effectiveness of wound sealant on bonsai and exactly which type is best. Many practitioners swear by cut paste and claim that nothing else works as well. In a thread at, Joanie Berkwitz stated, "…Sometimes it is a false economy to buy other products and expect them to work the same as cut paste. Cut paste has been developed for a very specific function... it allows callous to form underneath, it doesn't wash off, it contains anti fungal and anti bacterial agents that protect the open wound, it is not too stiff and not too soft. Sure, you can use plumbers putty or glue or other things... but you won't get all of the attributes of cut paste…."

Other bonsaists swear by other products such as Elmer’s glue, Vaseline, Play Dough, wax, toothpaste, dirt, and even Preparation H. The common denominator is the belief that trees need outside help in order to accelerate and assure healthy healing. Of course, this does not take into consideration that trees never actually heal. Damage never heals; it just isolates the damage through the formation of suberized, lignified wood that physically and chemically repels invasion. Callus develops at the edge of the wound and gradually expands toward the center. This wound wood remains for the life of the tree. When an animal is injured the response it the creation of new, healthy cells, when a plant is injured the response is to cover the injured area with callus tissue. Trees have been doing this since they existed without humankind’s help and certainly without foreign wound sealant of any type.

The Wikipedia tells us "Dr, Alex Shigo is widely considered the father of modern arboriculture. He developed many of the principles that have become central to arboriculture, and his work served as a foundation for much of the research following it." And that "Dr. Shigo's discoveries went against many arboricultural conventions that existed prior to his research. Many techniques that were staples of arboriculture for hundreds or even thousands of years were shown to be unnecessary or harmful. It took many years, but Shigo's conclusions have been confirmed by other researchers, and a wealth of discoveries are now built upon his initial work. Current ANSI standards for tree pruning reflect his recommendations."

Dr. Shigo debunked the myth of wound dressing decades ago, but the myth still persists and is still spread around, especially by retailers.

Diane Relf, Extension Specialist, Consumer Horticulture, Virginia Tech states that "An article by D.W. Robinson in Chronica Horticulturae points out that standard text books have traditionally recommended that when a tree is pruned, branches should be cut flush to the trunk or to a larger branch. After pruning, the cut surface should be painted with some substance to prevent rot. When decay develops, the wound should be cleaned out and the cavity filled. Research in recent years has refuted these recommendations." She goes on to say "Wound Paints and Sealants - While most horticultural books recommend the use of paints or sealants on tree wounds, Dr. Shigo's research shows that such treatments have no long-term value. Provided pruning is done properly by cutting as closely as possible to the branch collar, there is no need to paint wounds regardless of their size."

Thomas H. R. Hall, when reviewing Dr. Shigo’s book, "Tree Biology and Tree Care, A Photo Guide" sums up his thoughts nicely with the following words. "There will not be many arboriculturists or urban foresters in the temperate regions of the world who have not been influenced by the fundamental research carried out by Alex Shigo during his career in the Forest Service of the United States Department of Agriculture. His patient and methodical examination of decay patterns in the woody tissues of trees has revealed the mechanism of wound responses, indicating biochemical processes which isolate the invading organisms. No longer are trees treated like human beings to whom poultices, ointments and all sorts of medicines are applied to assist and encourage healing. Wound sealants are quite rightly relegated to nothing more than placebos whose only function is cosmetic. The concept of barrier zones isolating infection is epitomised in compartmentalization and walling off. Arboriculturists who have headed the findings of Shigo's research, require no further evidence to demonstrate the validity of his teaching."

Revisiting Linda Chalker-Scott, an Extension Horticulturist and Associate Professor at the Puyallup Research and Extension Center of Washington State University, we can find her thoughts on what wound sealants do and do not do.

Wound Dressings Do:

  • Seal in moisture and decay
  • Sometimes serve as a food source for pathogens
  • Prevent wound wood from forming
  • Inhibit Compartmentalization
  • Eventually crack, exposing the tree to pathogens

Wound Dressings Do Not:

  • Prevent entrance of decay organisms
  • Stop Rot

She goes on to explain in her article, "The Myth of Wound Dressings" that all plants, like all living organisms, have natural resistance mechanisms to fight insect attacks, disease, or damage. Covering wounds with sealants inhibits oxidative processes, which in turn will reduce callus formation and subsequent compartmentalization.

Sue McDavid, UCCE / El Dorado County Master Gardener, states that "First, tree wounds don't heal, they seal over. Painting them actually may harm a tree because some wood-rotting organisms may already be on the cut surface and if you paint over them, you're just sealing these harmful organisms into a warm, moist environment where they can grow and multiply. Prune at the proper time for a plant or tree and leave the pruning wounds alone."

Wound sealant, of any kind is not needed on a tree. Trees have evolved without dependency on artificial sealants of any type. They have a natural ability to deal with damage, be it by lightning, wind, snow, insects, disease, or the concave cutters of a bonsai artist. Dr, Alex Shigo, who is widely considered the father of modern arboriculture, proved this decades ago and yet the myth hangs on.

The fact is that applying any sort of dressing to a wound on a tree can be detrimental at best and damaging at the worst. Trees need to be left to their own innate devices when damaged, there is no valid reason for rushing in like Florence Nightingale with a first aid kit full of cut paste, band-aids, and other medications, all that will be done is to prolong the process of recovery. It may well make us feel better to think we are helping the tree, but in fact, all we are doing is adding to the chances of further damage.

Most wound sealants do not, contrary to some beliefs, come with anti fungal and anti bacterial agents that protect the open wound. The truth is the best protection for an open wound is no protection at all. Even those sealants that may actually have anti fungal and anti bacterial agents are suspect because the very act of sealing the wound most likely negates any advantage such additives would have by creating an environment far more friendly to bacteria and fungus.

Based on every single professional horticulturist and arborist statements on the subject that I could find, as well as studies from major universities, there is no other logical conclusion other than that applying wound sealants is ineffective, a waste of time and resources, and could hinder the recovery process and be damaging to the tree. All claims to the validity of using wound sealants are false.

The truth is that wounds do not need dressings and wound sealants can very well cause more harm than good to the tree.

Vitamin B1 Extracts


Another myth that just will not die is the use of vitamin B-1.

Miracle potions pop up from time to time shouting out the wonders that can be accomplished with just a few small drops of their B-1 enriched formula. Super-Thrive is the latest of these that I know of and one small whiff is enough to tell you that its main ingredient is indeed B-1. Someone always knows someone else that swears by this elixir of life and beginners are quick to try some of this magical concoction so that they too can have bigger, better, healthier bonsai, just like the pros.

The myth of B-1 spreads like the plague; it seems there is always someone crediting B-1 with reducing transplant shock, stimulating root development, increasing crop yields, and other such claims that sound too good to be true, and are.

I am sorry to say there is little truth in the claims of the advantages B-1 provides. Let us look at what the experts have to say.

Lauren Bonar Swezey in her article, "Does vitamin B1 help transplants take root?" stated that "…University of California research on vegetables failed to prove that B1 reduces transplant shock or stimulates root development. Researchers found "no discernible differences in color or vigor among treatments" when B1 and B1 plus iron, manganese, and zinc were used on peppers, pole beans, squash, sweet corn, tomatoes, and watermelons. Elsewhere, studies on chrysanthemums, citrus, and roses have reached similar conclusions."

Sue McDavid, UCCE / El Dorado County Master Gardener, states that "Using vitamin B1 to prevent transplant shock has shown no benefit whatsoever after multiple experiments, both in a laboratory setting and in the field, on a variety of plant species. Using B1 may make the gardener feel good and certainly the manufacturer, but your plants will be totally indifferent to it."

Looking again to Linda Chalker-Scott, an Extension Horticulturist and Associate Professor at the Puyallup Research and Extension Center of Washington State University, she states in her article, "The Myth of Vitamin Stimulants" that "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, aka thiamine, does not reduce transplant shock or simulate new root growth on plants outside the laboratory.
  • Healthy plants will synthesize their own thiamine supply.
  • Healthy soils contain beneficial microbes that synthesize thiamine as well.

It appears B-1 is just another myth that has been debunked in scientific literature by experts in horticulture and biology and yet refuses to die. B-1 or thiamine does not prevent or help transplant shock; it does not encourage root growth, and essentially does absolutely nothing for your plants as they manufacture their own thiamine.

Buying any B-1 based product is the same as throwing you money down a well, in fact in one study it was shown that the plants watered with plain water did better than those watered with B-1.

Based on every single professional horticulturist statements on the subject that I could find, as well as studies from major universities, there is no other logical conclusion other than that using B-1 is ineffective, a waste of time and resources, and produces no results. All claims to the validity of using B-1 or thiamine are false.

The truth is that B-1 has never been shown to be advantageous in reducing transplant shock or stimulating root development and other advantages such as disease resistance are still being studied.

The myths debunked above are just a few of the many myths prevalent in bonsai today. Through research and study, as well as a healthy application of common sense, we are able to cut to the core of the claims and reveal them for what they truly are, unsubstantiated hopes based on little, if any, actual facts.

I hope that we can put these myths to rest finally and focus on advancing the art of bonsai instead of hanging on to oldwife’s tales that serve about the same purpose as tossing salt over our shoulders when we spill it. Such actions may make us feel better, but accomplish little else.

Further Reading:
"101 Tree Myths" by Alex L. Shigo

"A New Tree Biology and Dictionary" by Alex L. Shigo

"Tree Anatomy" by Alex L. Shigo

"Modern Arboriculture - Touch Trees" by Alex L. Shigo

"The Growing Tree" by Brayton F. Wilson ( )

"The Myth of the Single Front" ( )


"Effect of Chemical Applications to Peach Bark Wounds on Accumulation of Lignin and Suberin and Susceptibility to Leucostoma persoonii". A. R. Biggs, Associate professor, West Virginia University

Linda Chalker-Scott, Ph.D., Extension Horticulturist and Associate Professor, Puyallup Research and Extension Center, Washington State University. ( )

\fs14fs14 "Tree Biology and Tree Management," by D.W. Robinson in Chronica Horticulturae 31(1). Originally published as "Minimizing Pruning Wounds," by Diane Relf, Extension Specialist, Consumer Horticulture, Virginia Tech, in The Virginia Gardener Newsletter, Volume 11, Number 1.

"Tree Biology and Tree Care, A Photo Guide" By A. L. Shigo, Klause Vollbrecht and Niels Hvass
Published by SITAS, Skovvej 56. 2750 Bellerup, Denmark, 1987 ISBN 87-982477-2-7

Plant Physiology Online by the American Society of Plant Biologists ( )

Wikipedia ( )

"Does vitamin B1 help transplants take root?" by Lauren Bonar Swezey ( )

"Beware of Gardening Myths" By Robert Cox, Horticulture Agent, Colorado State University Cooperative Extension ( )

"Gardening Lore" by Sue McDavid UCCE / El Dorado County Master Gardener ( ) thread "Work Arounds" post #10 by Joanie Berkwitz


Images used in this article are either in the public domain because their copyrights have expired, are licensed under the Creative Commons Attribution ShareAlike 2.5 License ( ), or permission has been granted to copy, distribute and/or modify such under the terms of the GNU Free Documentation license, Version 1.2 or any later version published by the Free Software Foundation.

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