Answer: Salix matsudana 'Navajo', the Navajo or Globe willow, is fast growing and thrives in wet soils. It is susceptible to aphids, beetles, caterpillars and scale insects which can cause loss of leaves, but so can heat or water stress. Weather related leaf drop in July and August really depends on where you live. If it's anywhere that's been experiencing extreme heat over the last few weeks, it's likely due to the temperature extreme shocking the tree into dropping its leaves. Don't treat your tree for insects unless you actually find them feeding on the leaves. If you don't see insect pests, the dropping foliage is probably due to summer weather.
Q&A Library Searching Tips