Bonsai pests!
If you had asked me, two weeks ago, if my bonsai were healthy and insect free, I would have said yes. At a glance, they all looked great. Looking closer, however, I discovered that one of my pines looked dirty.
Some dirt on the needles – this must mean…
Aphids! Aphids are most commonly found on bonsai with tender foliage, but they are not averse to feeding on pine. Fortunately, they’d only decided to inhabit one of my pines (and I can’t begin to guess why they chose the pine they did as it was surrounded by other pines that were completely free from aphids).
Aphids hanging out between needles
More aphids
Although they deserve swift attention, aphids are relatively easy to spot and eradicate – unlike the far more pernicious pine needle scale. I typically alternate between a variety of pesticides, oils, and soaps when I discover bonsai pests. After spraying, I watch affected trees closely to make sure the critters are truly dead and gone.
With the happy-go-lucky aphids under control, I took a closer look at selected trees in my garden only to find that my prime nemesis of late, the worm – master of camouflage and capable of munching every last variety in my backyard – has yet to vacate the premises. I plucked three from a hinoki that I’ve been spraying regularly for 6 months. I upped the dosage of systemic the tree has been receiving and promised myself I’d inspect the foliage more often. The worm’s camouflage makes it uncannily similar to the shoots it eats.
Tiny, well-camouflaged worm and hinoki shoot
These demented creatures even ventured to munch on my pines last summer. I’d never seen worms eat pine shoots before, but I’m determined to keep this from becoming a habit. (I wrote about them eating juniper shoots in “Juniper Pests.”)
A far more common foe to the pine is the tiny spider mite. They aren’t much to look at, but signs of their presence are unmistakable. Compare the fresh green needles in the photo below with the longer, yellowish needles from last year.
Spider mite damage
Spider mites like hot and dry conditions. They prey on weak trees before healthy ones, but if the conditions are right, they can cause significant damage to any pine in a matter of days. A haunting tidbit from Wikipedia: “A single mature female can spawn a population of a million mites in a month or less.” Yuck!
A simple test utilizing low tech equipment – 1 sheet of white paper – is a good way to spot spider mites:
- Hold sheet of white paper below a branch
- Tap the branch
- Inspect the tiny specs that fall onto the paper
1. Tap the branch over white sheet of paper
2. Check for mites
Before running out to check for bugs, I recommend you read Peter Tea’s account of Aichi-en’s battle against the bugs, “I love the smell of pesticides in the morning.”
Bonsai fertilizer – follow-up
Last month I began using tea bags filled with fertilizer to feed my bonsai. Unfortunately, it only took a few days for me to realize that this technique didn’t work well as implemented. The bags started disappearing immediately. Critters tore through some of the bags and carried others away completely, leaving behind the toothpicks that were meant to keep the bags in place. Somehow they removed all of the bags from my best trees and only a few of the bags on the developing trees – I won’t even try to solve that one. Instead, I’ll go back to my time-tested fertilizer method – clumps of cottonseed meal and fish emulsion.
Tea bags intact on a pine forest
Tea bags on an exposed root pine
Cottonseed meal on a pine
More cottonseed meal
I usually start feeding my trees at some point between late January and mid March depending on the weather and the variety. If I’ve repotted a tree, I wait about 4 weeks before feeding it. I start by placing one or two clumps of cottonseed meal and add additional clumps every 1-3 weeks later until the majority of the pot is filled with fertilizer.
Cottonseed meal feeding a recently separated cryptomeria
I supplement the cottonseed meal with fish emulsion (see “Bonsai Fertilizer” for details). Fish emulsion is a great, if stinky, fertilizer that I’m comfortable using on all bonsai varieties. I usually apply fish emulsion weekly, though I might apply it more or less frequently at various times depending on the season, the weather and the variety.
Fish emulsion
Ebihara fed his trees with diluted liquid fertilizer every three days (I don’t know what type of fertilizer he used). Others primarily rely on dry fertilizer that releases food whenever the trees are watered. I haven’t noticed big differences between liquid, dry, or other categories of fertilizer, but I do find that consistent application leads to the best results. And the best results, of course, depend on the goal of the fertilizing program. If I’m trying to increase the size of the trunk, I fertilize a lot. If I’m trying to ramify delicate branches on deciduous varieties, I fertilize very lightly and only after new leaves have hardened off.
As for the tea bags, I haven’t completely given up. I may yet try chili powder or some other caustic agent that’s harmful to vermin but safe for trees. And if I can get this right, I will celebrate and then post the results.
New hinoki bonsai
I recently picked up a couple of large hinoki cypress with the aim of developing them as bonsai. They seemed healthy and had good sized trunks so I thought they’d warrant the effort.
Hinoki cypress - Chamaecyparis obtusa ‘Tempelhof’
Adding new trees to my collection never seems overly burdensome. I simply remove a few branches and repot the trees. Beyond that, they typically require little more than water and fertilizer for the remainder of the year.
Of course, this changes – sometimes dramatically – a few years down the road. If I find I don’t have the time to give a tree the attention it deserves, I move it along.
Trunk detail
Based on what I could see above the soil line, the tree looked like it had a nice trunk. Finding the rootbase, however, would provide more useful information. As the rootbase was large, I grabbed a large chopstick and got to work.
Key repotting tool – large chopstick
The rootbase, it turns out, started about 6″ below the soil line. When I found it, I noticed a significant graft line. I continued bare-rooting half of the rootball and potted the tree in my standard mix of akadama, pumice and lava.
The graft line
The lower part of the trunk is likely chamaecyparis obtusa, the rest of the tree, ‘Tempelhof.’ As the graft line is striking, I’m considering ways of improving the appearance of the lower trunk. I’ve thought about burying it, creating an air-layer, or simply living with it the way it is. I have no experience air-layering hinoki, and have heard mixed stories about its feasibility, so I remain curious about this option. I don’t think I could actually bury the nebari, which means I may end up living with this line.
After cutback and repotting
I have a year to think about it. For now, I’ll focus on watering and fertilizing the tree, and delay any more dramatic decisions until next year.
Omoshiroi red pine forest
“Omoshiroi” means “funny” or “interesting” in Japanese. It can be used to convey respect or mockery – which makes it a useful term for bonsai.
During a Bay Island Bonsai workshop hosted by Daisaku Nomoto, I brought in a red pine forest I’d grown from seed. Nomoto found the grove to be omoshiroi. He took some interest in the forest, insisting that I bend two of the trunks down and remove a large branch from the main tree. He wasn’t concerned about the unorthodox character of the composition or the lack of taper – the forest was omoshiroi. I asked if I should wire the rest of the branches – Nomoto didn’t think they needed it. The branches didn’t need a lot of attention because carefully detailed branches wouldn’t match the unusual trunks. I thinned new shoots to one pair per branch and removed the old needles.
Red pine forest – before cutback
After cutback
I’ll wire a few of the main branches when I decandle later this spring. It looks like this forest might be my best candidate for next year’s BIB exhibit, but it’s too early to tell just yet. I’ll know more in fall when the summer growth fills in.
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