Help- early fall for Wisteria?
I have a dozen well-established wisteria in pots on my deck in South Baltimore – some of which have been thriving for almost 20 years. Suddenly, five of them are turning brown and losing their leaves. I doubt if it's water, since the others on the irrigation system are doing fine. Could it be scale, or borers? They are vigorous plants, and should recover if I can find the cause, and the solution. Thanks!
After all those years in pots, they may be completely rootbound, as they are vigorous growers, as you know. There may be virtually no soil left in the pots. They may need bigger pots or new soil. Potting soil can be added each year to the top of a pot, or the plants may need to be removed, roots trimmed, and repotted in fresh soil. You also don't mention fertilizing them. They must get nutrients from somewhere to survive.
We can't say if there are scale insects or borers without seeing photos of the plants. Scale insects should be visible to your naked eye.
Send us photos if you can.