Update: Took a core sample of soil. The soil was saturated in water and within 7 inches or so it's practically clay. I think the plant is being over watered and is unable to drain. I increased the watering about 3 months ago (I use a drip system), which most of the garden has benefited from. But this particular spot is in between two slabs of cement and at the end of the fence so perhaps it's harder for it to drain.
The other vines a few feet away are healthy and their soil is not saturated.
So I will scale back the watering and perhaps close off this particular drip for awhile so it can drain out. I'm also trimming off some of the dead leaves. We'll see how it goes.
If anyone has other suggestions or insights please let me know.
Regards,
