Last summer I planted a rather large wisteria. It flourished. I live in the high desert, so it got a couple of gallons of water twice a week, all winter and once it stated leafing out, I turned on the watering system. Started out looking good, but now the leaves are all yellowing. I'm at a loss, other than I'm pretty sure it getting plenty of water as everything else on that leg of the system is doing fine. Ideas?