by Ross Clark

Complex plants began adapting to land around 420 million years ago, so they’ve had ooodles of time to get their act together.  During that time, plants have experienced and adapted to wide swings of extremes in the physical environments they inhabit.  Consequently, they tolerate the unusual (or sometimes downright outlandish) conditions we impose on them when we work with them as bonsai.

In other words, the genetic flexibility built into plants through 400 million years gives them the means to tolerate a lot of things we do to them.  That is why we can do many things to them and get away with it, and that is why there are many "right" or successful ways to water, fertilize, winter, prune, propagate, and do everything else we do to bonsai.  And that in turn is why bonsai artists collectively swear by this or that technique–and why many people have personal systems that work.  Some bonsai artists maintain that there is only one right or best way to do things.  However, when someone presents a technique as the only approach, it implies that they have tried all possible approaches under all conditions in order to arrive at the ultimate truth.  Should we be just a mite skeptical of such dogmatic positions?  It’s also a good idea to keep in mind that bonsai in their great genetic wisdom will even tolerate unnecessary things we do to them, even though we may be misguided.  We may think we’ve found the best way, when we have only discovered one approach that our trees will tolerate.  

Yes, there definitely is some bonsai folklore out there.  Really? – plant folklore?  Well, the elderly lady who lived next door used to advise me never to plant an odd number of landscape plants, because (she said) if you were to plant an odd number, they would always die until an even number remained. (It's a true Kentucky fable!).

Let’s return to the main point.  In an earlier issue of this newsletter, Dave Bogan (April 2008: Is it Myth or is it True) took on some items of bonsai folklore.  I think it is worthwhile to review his points and add a few more.  Briefly, Dave's points included:

• Wire left on in the summer might heat up and scorch branches
• Never water plants in the mid-day sun, because you might burn the leaves
• Always make pruning cuts at an angle
• Never cross wires when wiring
• Soil mixtures are critical

I agree with Dave Bogan that all of the foregoing statements are flawed.  The second one is especially widespread and ridiculous.  Have you ever seen it rain while the sun was shining?  And then the leaves develop small lesions, wither and die, don’t they?

Here are a few other sacred cows I feel should be prodded.

If you prune it in spring, a tree could bleed to death.

The truth is, trees become strongly hydrated in spring, and sap indeed does flow freely.  However, plants have physiological methods for sealing injuries and will not be damaged by reasonable pruning in spring.  There are certain conditions and seasons when plants may be more susceptible to fungal infection, but that is a separate issue.  In short, the best time to prune is worthy of discussion, but the statement above is folklore.  And comparing plant sap with blood is like comparing apples to kumquats.  Sap and blood both contain water, and that’s about where a valid comparison stops.

You should seal pruning cuts on pines.

Healthy pines produce large amounts of resin.  Resin in healthy pines is under considerable pressure and quickly seeps out of numerous ruptured resin ducts whenever an injury occurs.  The positive pressure of the resin quickly seals the wound.  In addition, conifer resin is toxic to most organisms.  There is no better sealant for pine wounds than pine resin.  Anything added is like putting lipstick on a pig.  So, why do the masters do it?  Draw your own conclusions.

Sharp soil particles encourage roots to branch more by stimulating the root tips.

The business end of a root is well protected.  Cells at the tip of a growing root secrete slippery mucilage that lubricates the root tip as it moves past soil particles and through organic material.  In addition, the tip end of a root has a structure called the root cap, which consists of a thick layer of cells.  The root cap cells continually wear away as the root tip advances through the soil.  So, under natural conditions, it is very unlikely that sharp edges of soil particles have much influence on root branching.  However, when bonsai pots are moved or rearranged, it is possible that small injuries could occur to young roots, and small injuries could possibly stimulate branching.  Most likely the shape of soil particles has little direct affect on root branching.

Vitamin additives reduce transplant shock and encourage rooting.

Animals like us cannot produce their own vitamins from scratch.  We must get them or their precursors from our food or from microorganisms that inhabit us.  So naturally, it is easy to think that perhaps vitamin supplements can increase the health of everything.  But the fallacy is that, unlike us, plants produce all of their own vitamins, and don’t need any from outside themselves.  There is no experimental evidence that shows plants respond to added vitamins by increased growth or greater health or increased stress resistance.  It’s just not so.  Believe what you want to, and keep buying that thriving potion if you want to, but the evidence says it is a waste of money.

Healthy plants that are carefully and properly transplanted will begin to grow new roots almost immediately.  Growing new small roots is the main way that plants recover from transplant shock.

Plants grow better if you pray for them.

Maybe you've heard this one, too.  My perspective is, if you pray for something, it probably means you are paying it close attention.  Bonsai benefit from close attention.  Also, if you exhale deeply while praying, the carbon dioxide you emit could increase photosynthesis by a small amount.

Organic fertilizers are better than inorganic fertilizers.

The topic of fertilizers is worthy of very extensive discussion.  However, the short answer is, plants don’t differentiate between whether the soil nutrients they require come from organic or inorganic sources.  There is no qualitative difference in potassium ions from an organic source and potassium ions from an inorganic source.  Botanically, there are advantages and disadvantages to all types of fertilizers, but that is another story for another time.

If I have flogged a sacred cow or two, or contradicted a bonsai master or two, please do not shoot the messenger.