Spring is a great time for defoliation – the removal of leaves from deciduous bonsai. As defoliation is very stressful for trees, it’s only for healthy specimens that respond well to the procedure. I’ve learned from past experience that fully defoliating my Korean hornbeam can lead to dieback of weak, interior shoots. Now I partially defoliate the tree, taking care to preserve leaves on weak or interior branches.
One aim of defoliation is to get more light into the tree’s interior. As you can see from the photo below, the foliage on my hornbeam is so dense that little light reaches the tree’s interior.
As spring is also a good time for cutback, I shortened new branches to about two leaves and removed all large or downward facing leaves. I used scissors for the cutback and plucked most of the leaves by hand.
Here’s a peek at the first third of the work.
Here’s what the tree looked like when the work was completed.
After defoliating – from above
And here’s the view from the front.
Korean hornbeam – after partial defoliation
From the left side
You’ll notice I was fairly conservative with the leaf removal. I know how the tree responds to full defoliation (see Defoliating a Korean hornbeam part 2) and am curious how the more conservative approach will work. Over time I hope to hone in on the best approach.
This Saturday, I’ll be demonstrating spring deciduous techniques on a trident maple at the Napa Valley Bonsai Club’s annual show in Napa, CA.
The exhibit runs from 11:00 a.m. to 4:00 p.m. The demo starts at 1:00 p.m. I’ll also be vending with tools, pots, supplies and trees available. If you’re in the area – come by and say hello!
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Alex Voorhies says
Thanks for the post Jonas, these are really fantastic. When you are defoliating a deciduous tree and you cut back a long runner, do you leave one leaf at the end, or defoliate the first couple leaves to open up the interior buds? Would you do it differently on an ume or crab apple?
Thanks again for such great documentation!
Jonas Dupuich says
Hi Alex – good question. If the runner is too vigorous and/or thick at the base, I’ll remove it entirely. If I leave a bit, I may or may not leave some leaves at the base depending on whether or not they block the light of nearby branches. I haven’t defoliated crabapple or ume. For ume, I generally prune to silhouette once a year, and as for crabapple, I just started a batch so we’ll see down the road a bit.
Such great information Jonas! Love the reinforcement that not all deciduous species, or even trees within a species will respond the same way to a technique or procedure. I, for one, need constant reminders. Also loved the time lapse video.
Sage Smith says
Nice post. I hope you have good attendance to your demo. Spreading the word of bonsai!!!!!!!!!!