I planted a 2.5/3' tall vine maple in my backyard about 6 weeks ago. It's in full sun, which I know wouldn't be it's first choice, but I thought they could handle it here in the PNW. It has definitely not dried out - I've been hand-watering religiously due to our warm spring, and it's mulched to help keep the soil moist. It has two main stems, both of which come out of the soil (not one branched off the other). I just noticed that all of the leaves on one of the stems, every single leaf, has turned completely crispy dry. They didn't wilt at all, and they turn dry/brown around the edges first. The leaves have kept their shape perfectly. The colour has faded somewhat, but there's absolutely no browning, not even a little around the edges. They are just totally desiccated. It's so strange. Does anyone know what this is? Is the tree a goner? Right now the other stem still seems okay, although the leaves have turned red where the face the sun (which had happened on the dead stem too, and on the two other vine maples I planted at the same time, both of which also seem fine).