If the temperature drops into a freeze, the leaves can quickly freeze, turn brown and fall off, with no transition to color. A friend discovered a vine winding up a tree. These bloom for months and take plenty of sun and a well-draining soil. Mulch the roots this fall to ensure winter protection. Tell her to prune it next spring when the vine begins to put on new growth.
Some potato vines reseed.
It was green and is now a purple-brown. I love it. The leaves you sent were crumbled, but I believe you have a sweet potato vine, Ipomoea batatas, a trailer related to the morning glory. These fast-growing ground covers or vines are treated as ornamentals, not as edibles. They also are treated as annuals, so you might want to take some cuttings so you'll have starts next spring.