Tree Tips

August 2024

Ahh, the lazy, Dog Days of Summer…

...NOT!!! I find that this time of year, June through mid-August, is one of the busiest and most productive and impactful times of year for working on my trees. Yes, it has been excruciatingly hot and unpleasant out in the sun, but it's the core growing time for the trees. I have been cutting back, thinning and defoliating where needed, and wiring and shaping my trees, especially the deciduous and broad leaf evergreens for the past couple of months. 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 19th), 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.

Caring for Trees in the Hot Months

We're going into the record books for hottest days this year, so do remember to water up to two times a day if you see wilting on these hotter days. Again, this has been a brutal year so far, heat-wise. However, 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 and it can damage later flowers and developing fruit. Watering the foliage early in the morning acts like dew. In fact, if you have trees that are battling mites or other insects that like hot, dry and cramped conditions, you can wash and blow them off without using chemical treatment by heavily misting them. 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 an Aqua Crest Garden Hose Filter (a hose-end filter) that works quite well and doesn't leave water spots and calcium deposits on my pots. Got it online.

Cutting Back and Wiring

Rotate your trees. Trees are heliotropic — growing toward the sun. Get them looking good from every direction. The sun will be getting slowly lower in its trajectory through the sky, but now it can really make a difference.

Pinch, groom and keep working on your show trees so they will be ready when show time comes (October 19th). 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 Care

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 into the bark. If the branches are small, unwrap the wire 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 the branch run until January/February 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.

Fungus and Insect Control

Watch out for signs of fungus damage. Bi-weekly, spray a fungicide in the evening like Cleary's 3336WP®, Daconil Ultrex®, or Zerotol®.

Honeydew, a shiny and sticky substance on leaves, is a sign of sucking insects in the aphid family. The insects can't digest all the sugar they get from the plant, so they deposit it on the foliage. Many times, ants, which love the honeydew, will cultivate the aphids, whitefly and scale that produce it. You might also 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. Scale 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 with a second application one 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.

Protecting Potted Trees

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. 🌳