Tree Tips
August 2021
This month I will be doing a styling demo of a collected Coast Live Oak that I acquired from Steve Awaki At the Sei Boku Bonsai Kai sale earlier this year. It should yield an interesting bonsai which I will put in the September First Thursday meeting silent auction. If you have oaks you would like to have me look at for advice, bring them in. I will, time permitting, do my best to give you suggestions.
“It’s not a good idea to water the foliage after dark, but you can still water the soil.”
Remember to water up to two times a day if you see wilting on these hotter days. It’s been a brutal year so far, heat wise. It’s not a good idea to water the foliage after dark. Moisture on the leaves in the evening will remain for hours or totally overnight; the moderate coolness of night plus moisture is the perfect growing environment for fungi to form and grow. It can also damage later flowers and developing fruit. But, you can still water the soil. In contrast, water or dew in the morning will evaporate from the leaves once the sun hits it and the day warms up.
If you’re having some water quality issues, I’m using a hose-end Aqua Crest Garden Hose Filter that works quite well and doesn’t leave water spots and calcium deposits on my pots. It is available online.
Rotate your trees. Get them looking good from every direction. The sun is getting slowly lower in its trajectory through the sky so it can really make a difference.
Pinch, groom, and keep working on your show trees so their ready when show time comes. Anyone who has a supply of sun moss, the kind that has a silvery look to it should be saving it for the top dressing. If you have seen any sources for moss, please pass it on. My sources are burned out.
Deciduous tree Alert!
Watch your wires. The explosive growth we have had since spring is expanding the branches rapidly and the wires may be cutting in to the bark. If so, unwrap the wire rather than just cutting it off. If, in removing the tight wires, you cut into or expose any cambium tissue, dab it with a little tree seal so it won’t dry up and form a weak part of the branch. When you later wire that branch with the weak part and try to bend it, it can break right there and you’ll be wondering why it happened.
Branches that you are developing from scratch must be wired down and allowed to run and thicken to develop that first critical movement out from the trunk. Let it run until the fall when you will cut back to start your next segment of the branch next year. On your refined trees for the show, you will notice that the growth usually slows down around now with the high temperatures. If you have been pinching throughout the season you probably notice that it is not quite as quick to throw out vigorous new growth about now. Let the growth elongate a little. We will be having another growth spurt at the end of the month and cut back before the show and do some show wiring to dial the tree in.
Pest Control
Watch out for signs of insect and fungus damage. Spray a fungicide bi-weekly in the evening like Cleary’s 3336® WP, Daconil® Ultra, or Zerotol®. Honeydew, a shiny and sticky substance on leaves, is a sign of sucking insects in the aphid family. They can’t digest all the sugar they get from the plant and deposit it on the foliage. Many time ants, which love the honeydew, will cultivate the aphids, whiteflies, and scales, which produce it. You also might see a dirty substance called sooty mold, which grows on the honeydew. This readily washes off, but the insects may not, so spray with Malathion®, Diazinon®, an oil like Ultra Fine® or Neem oil, or a systemic insecticide like Orthene® to control these problem insects. Scales are resistant because of their hard shells, but can be picked off easily. Apply any spray in the evening to minimize damage to your trees. Wash off any oils thoroughly!
Look for splotchy or speckled foliage that might indicate spider mites. Hold a piece of white paper under a branch and tap the foliage above it. Rub your finger over whatever is on the paper. If it smears — yuk! — you probably have spider mites. Zap them with a jet spray of water to knock them off. Do this every three days for a week. If you still see evidence (smears) spray every third day with Safer® Soap. Lastly, try spraying a miticide on the underside of the foliage. And one a week later. Remember that spider mites are arachnids, not insects. The foliage will not immediately turn around and look healthy — the mites suck the chlorophyll out! New growth, however, should be regular color for the species you are treating.
Mildew and other fungi thrive in the warm moist crevices of the tree when we mist or over spray the foliage. Daconil® is a good broad-spectrum fungicide that can be very effective on this problem.
Trees that are growing in the ground really benefit by having full exposure to the sun. Those in nursery containers need a little shade, especially late in the day, and those in bonsai pots need considerably more shade and, especially, surface protection. I have been using a top layer of shredded sphagnum moss/ green moss to keep the surface soil moist, to promote surface roots and to insulate the root system from the Sun. Also, try using shade cloth (30-40%) overhead to cut the sun. Except for Bougainvillea, crepe myrtle, black pines, olives and peppers and the like, which seem to drink up the sun, this will help your trees during this stressful time. This will help them stay green and show their best. 🌳
