Pat, According to all the pros there is no fungicide that works on clematis wilt. Some say the wilting is caused by the plants inability to take up enough water in hot weather. Planting deep, so the root ball is at least two inches below grade is said to help. Also placing a flat stone over the roots helps to keep them cool and moist. I would fertilize the clematis with a kelp and fish fertilizer, such as Neptune's Harvest a couple times during the season. Hope this helps, Best Nancy.