Clematis plants (Clematis spp.) are mostly deciduous flowering vines, which grow in U.S. Department of Agriculture plant hardiness zones 3 through 11. As long as you plant a species that is appropriate for your hardiness zone, you shouldn't lose vines to frost. Newly planted vines or clematis that begin to bud in the spring can suffer damage from a late spring frost, however, as new growth hasn't had time to harden off. Take precautions when a frost is in the forecast and your clematis should bounce back as the spring progresses.
Soak the soil surface around the clematis' root zone the day before a late frost is expected.
Avoid cultivating or covering the soil with new mulch until later in the spring. Both of these actions make it more difficult for the soil to retain heat. If mulch is already around the clematis, scrape it away as early in the day as possible to allow the sun time to warm the soil. You can replace the mulch when the frost danger is over.
Drape a frost cloth over the vine before the sun sets the evening before the frost. Hang the cloth from stakes around the plant or use a trellis structure to support the cloth if the vine is on one. The cloth needs to cover the vine to ground level without touching the foliage.
Remove the frost cloth in the morning when the temperature warms and the frost danger has passed.
Allow the clematis vine to retain all the foliage after a frost even if some leaves appear wilted or damaged. The foliage may recover; and if another frost occurs, the added leaf cover will help insulate the vine.
Clip dead leaves from the vine when you see new growth appearing on the clematis. If a vine tip is injured and has many dead leaves and no new growth, use pruning shears to cut the vine back to healthy tissue. Make the cut just outside a leaf set, bud or branching stem.
Feed with a general-purpose fertilizer after you prune your frost-damaged clematis vine. Dissolve 1 tablespoon of fertilizer in 1 gallon of water, and apply to the soil over the root zone of the clematis.