my vine is old. it bloomed this spring, bit now the leaves are turning yellow and mottled and the whole plant is dying back. What can I do to save it?
Yellowing leaves could be watering issues; drought or excess rainfall, pests, or more serious Leaf Blight.
Inspect the plant carefully for any other identifying leaves or markings on the plant.
Most pests can be treated with Neem Oil and fungus can be treated with a Copper fungicide application.
Here are some links to help you.