Matthew Nistico wrote:Generally speaking, trees will unexpectedly drop leaves like that under environmental stress. In my experience, this usually means too hot and/or too little water. I have planted many black locusts on my property, which is right at the edge of their native range. I see a few around my area, but mostly they begin appearing 30-minutes by car further up the mountains. Predictably, on my land they drop leaves by the end of summer, only to regain them as cooler autumn weather sets in, only to loose them again over winter.
While this is clearly a stress response, it is not enough to seriously hurt the trees - they still grow like black locusts, which is to say like weeds. Were I in an even warmer zone, doutbless I'd have trouble growing them at all. But by the same logic, the stress response is specific to these trees based on their growing preferences. I have seen a similar pattern in currants and gooseberries I've planted, similarly at the very edge of their tolerance for hot conditions, but not with countless other species more well adapted to my zone. That doesn't mean there is anything "weird" about the weather, only that certain species can handle it while others struggle. Whereas the black locusts are clearly winners for me, despite their challenges (and their thorns!), I've yet to decide if I shall give up on the gooseberries or keep trying to nurse them along at the edge of their ability to thrive.
BTW, I have noticed that now, in mid-August 2026, my black locusts have yet to loose their leaves. This has been a fairly cool and notably wet summer for me. Surely, that is no coincidence.
Of course, the pattern described above assumes that your plants suddenly dropping leaves out of season will in fact bounce back at a later date. If they drop leaves suddenly and then die, it may well have nothing to do with their climate tolerance; they probably contracted some virus. Of course, having said that, if they exist in a stressed state due to extreme heat relative to their preferences, they were likely more susceptible to disease in the first place by virtue of being stressed.