Answer: Dark green leaves usually indicates a droughty condition. The vines were healthy early in the spring and then wilted from a lack of soil moisture. Once the plants begin to wilt, the tissues in the leaves will be damaged - probably beyond repair. I'd cut the damaged vines down to healthy tissue and allow them to resprout. As long as the roots are still alive, they should develop new stems and foliage. Water deeply and regularly to keep the vines happy and don't fertilize any more this season. Best wishes with your plants!
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