Tree Tips
August 2026
Yes, it is a little hot and unpleasant out in the sun, but it’s the core growing time for the trees. I love this time of year. June through mid-August is one of the busiest and most productive and impactful times of year for working on trees.
You saw on the back yard tour how much I’ve been cutting back and defoliating, and what kind of response I’ve gotten. The past couple of months have also been a time to shape and lightly wire my trees, especially the deciduous and broad leaf evergreens. Now I have so many shoots that I need to pinch the new growth before they get too long, and to keep the internodes (distance between leaves) short and maintain the silhouette of the tree. Of course, I’m not transplanting at this point.
When working on trees that you will want to show this year (October 3rd) remember that it takes a number of weeks for cutting back to produce new shoots, and a few more to have the foliage harden off. So, plan ahead for your trees to show their best.
It’s not a good idea to water the foliage after dark as a moist condition on the leaves can lead to mildew in the warm summer evenings. It can also damage flowers and developing fruit. But, if you heavily mist your trees in the morning it acts like natural dew, and you can wash and blow off mites or other insects that like hot, dry and cramped conditions without using chemical treatment. I had some spider mite problems and this has really helped. Give the sun and wind a chance to evaporate the surface moisture on the foliage before dusk. But, you can still water the soil. (I’m using a hose end filter, the Aqua Crest Garden Hose Filter that works quite well and doesn’t leave water spots and calcium deposits on my pots.) Got it on line.
Rotate your trees. Trees are heliotropic - growing toward the sun. Get them looking good from every direction. The sun will getting slowly lower in its trajectory through the sky, but right now that rotation can really make a difference.
Any one 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.
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 the wire is small, unwrap it rather than just cutting it off. If the wires are larger cut them off so as not to knock off freshly formed buds or shoots. Also, 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 could break right there and you’ll be wondering why it happened.
Branches that you are developing from scratch must be wired and allowed to run and thicken to develop that first critical movement out from the trunk. Let it run until January/February when you will cut back to start your next segment of the branch. 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 around this time. Let the growth elongate a little. We will be having another growth spurt at the end of the month and can cut back before the show and do some show wiring to dial the tree in.
Watch out for signs of fungus damage. Bi-weekly, spray a fungicide in the evening like Cleary’s 3336 or Daconil Ultra or Zerotol for powdery mildew.
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, whitefly 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 use Merit® granules or spray with Malathion® or 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 what ever is on the paper. If it smears red (Yuk!) you probably have spider mites. Zap them with a jet spray of water to nock them off - do this every three days for a week. If you still see evidence (smears on the paper) spray every third day with Safer Soap. Lastly, try spraying a mitecide on the underside of the foliage, and again 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 chlorophyl 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 for 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, a little shade will help your trees during this stressful time. This will help them stay green and show their best.
Don’t forget to fertilize your trees.
