Bonsai Myths
exist are commonplace on the internet, in print and amongst many
groups of enthusiasts. Akin to the computer virus, they raise
their heads on occasions, are suppressed, disappearing from sight
for a few months or years before reappearing again and again and
again.
Though all evidence can be put forward to fight the myth, it only
takes one popular bonsai title to perpetuate the myth for years;
"it must be true, I read it in xxxx xxxx's book".
The bonsai trader has read the book, the club member has read
the book, the forum member has read the book and the myth is spread
around and around and around.
MISTING
INDOOR BONSAI
My first line of attack is aimed at Misting Your Bonsai Daily.
Many beginners in particular are encouraged to mist their trees
regularly, primarily to increase the humidity around the tree.
No doubt that this does temporarily address the arid indoor atmosphere
in which many bonsai are expected to exist. Unfortunately, misting
only creates a temporary humid atmosphere.
What does frequently occur is that the excess water from misting
or spraying, runs off the leaves into the soil below. A frequently
misted tree will in effect have water running onto the surface
of the soil on a frequent basis. This can often create a soil
structure where the surface of the soil is continually wet and
airless; something that often leads to poor vigour and even root
rot in trees, particularly in poor draining soils.
The other problem with water run off is whilst the soil surface
can be wet and indicate that the tree does not require watering,
the underlying mass can be dry because there has not been sufficient
run off to penetrate past the upper 1" of the soil mass.
Because the enthusiast believes the soil is still damp he or she
have failed to water the soil directly. How can you tell whether
the soil is wet or dry if the surface is continually misted?
Trees grown indoors do need misting once a week/fortnight. Leaves
naturally collect dust and the easiest way of cleaning them is
to give the tree a thorough misting or spraying. But that's all.
NEVER
WATER YOUR TREES AT MIDDAY
A closely
related myth. This myth instructs us not to water a tree in bright
sunlight lest the leaves are burnt by the magnifying effect of
water droplets.
As a UK resident we rarely (never) experience sunlight strong
enough to burn leaves, however well the water droplets might magnify
sunlight. I have great doubt that the concave upper surface of
a water droplet would be able to focus light onto a leaf in anyway
at all.
Anecdotal evidence from enthusiasts who regularly experience Summer
temperatures of 100°F or more similarly have no experience
of 'water induced leafburn' (!).
My prime reason for disbelieving this myth is that if water droplets
caused leafburn why does this event never occur when it rains
on a hot day? Surely the myth would lead us believe that the trees
around us would be burnt and possibly defoliated every time there
was a rain shower during the Summer?
To quote a more authoritative source, Professor Amy Liang in her
book the 'Living Art of Bonsai' states that "if sunlight
goes through a drop of dew directly, its energy is only 0.2 calories
per minute. It is, therefore, incapable of burning leaves..........In
addition, 1/4oz of water absorbs approx. 540 calories of heat
when it evaporates , it is clear that instead of scorching leaves,
water helps lower temperature (of the leaf surface)".
So where does
this myth originate? I believe it maybe a result of the old gardeners'
advice to never water your garden during the day. Flowers and
in particular, the flowers of garden annuals do spoil if they
become wet whilst they are fully open during daylight hours. The
reason they spoil has much more to do with the impact of heavy
water droplets on the delicate, light petals of a flower than
of any effect from the Sun.
Spraying the
leaves of outdoor bonsai with water can useful for reducing the
effects of high summer temperatures and cleans the dust from the
leaf surface but with reference to the first part of this article,
it is not necessary on a daily basis and should only be carried
out at the same time as watering a tree whose soil actively requires
water*.
