Virginia Creeper wilting?

I have two Virginia Creeper plants growing on a mound behind my pond. They're planted about two metres apart. They both roared into life a few weeks ago but suddenly the one on the right is wilting badly. The left plant is 100% perfect.
They were planted at the same time at the end of 2008 and grew at the same speed.
They are growing in the spoil dug out for the pond. It is clay but quite sandy at the same time. When dry, it's rock solid.

My neighbour has been battling with a bramble bush and asked if it was okay to use weedkiller, knowing that I had plants this side growing. I wasn't fond of the idea but assuming they were careful, I guessed it might be okay.
The plants I was concerned about was the new hedge I have growing which is at the same ground level as their brambles. These creepers as seen in the pic, are about a metre or so higher than ground level.
I'm wondering if the weed killer was 'blown' my side and wafted over my creeper.
At a similar time I also watered the creepers deeply so maybe it was down to me... but the left creeper is fine!

The first creeper on the left, the Bay Laural in the corner, my hedge and Periwinkle on the mound are all totally unaffected.

It appears to be growing vines so it's showing signs of trying to march on but as I say, the leaves are shriveling up and wilting. Not many have fallen, but they have shrivelled and shrunk to virtually nothing.

To say I'm not happy, is an understatement. However, if it does continue dying I'm not overly concerned PROVIDING it will ultimately recover.

Can anyone think of what may be the reason for this? have any idea if it could recover?

 

Hi there

I have a similar problem with my VC. Did you find the cause, or observe the creeper recovering?

 

I'm strongly going with the weed killer. I pulled off the wilting leaves and brushed off the crispy dead ones with my hands and what's left appears to be hanging in there. It's also sending out new vines and reaching for the sky still, albeit not as vigerous as the other V. Creeper next to it.

I'm watering it and feeding it and it looks like it might be okay. But I have to train it to fill in the huge bare patches. It's still fairly new, so maybe it isn't quite self sufficient enough regards water.

I've read this vine is almost indestructible so hopefully watering and feeding might help yours too?