We certainly know about hot weather down here in Houston. This is the first year I’ve lost plants to the heat, and they were lost early on.
Leaf scorch can be bacterial or it can be caused by dry windy conditions. There is no hope for plants with the bacterial leaf scorch. For those with it caused by windy, dry conditions you can help. Plants take up moisture through the roots and disperse it to the leaves where some of it is evaporated to cool the plant. On windy days more moisture is lost from the leaves. Plants need to be able to take up more moisture faster to replace it. You’ll see leaf tips turn brown and it can progress turning all the leaves all brown before stems wilt and the plant dies. More water is the answer to this. Water regularly and deeply so plants can reach water deep down in the soil.
Too much sunlight will turn your leaves from green to white. If you see leaves bleaching out provide those plants with more shade.
Fertilize less in July and Aug. The plant can’t handle the heat and new, rapid growth. I fertilize heaviest in the spring and the fall and not at all in the summer and winter. But summer thunderstorms can rapidly deplete what little nutrients we have in our soil. If you see yellow leaves with green veins add some iron and nitrogen to your soil. Half the recommended strength is best for summer fertilizing.
Mulch. Mulch greatly cuts down on water loss and it helps keep those roots just a little bit cooler. In time it will break down and add badly needed organic matter to the soil.
If plants are wilted in the afternoon and the ground is not damp, give those particular plans a deep watering with your garden hose. Let it trickle out slowly for a long time.
No matter where you live, your trees are trying to maintain a leaf temperature of about 70’F. There is every reason to think that other plants do the same. This is the temperature at which photosynthesis takes place. The control of the temperature is done through water uptake. So give your plants the water they need and keep things well mulched.