QUESTION: I love the foliage and flowers on the wisteria vines hiding our tall concrete retaining wall. But in the winter, when the vines drop their leaves, the wall looks nude. What vine could I plant to grow with the wisteria and provide winter foliage?
ANSWER: Co-habiting with established wisteria vines is not easy because these vines are greedy growers. If root space is available, try planting lilac vine (Hardenbergia comtoniana), a shrubby Australian vine with purple flowers, in early spring. Because the lilac vine retains its foliage, you won't have a bare wall in the winter.