Can Pulling Out All of the Dead Leaves Kill Sweet Autumn Clematis?

Growth Characteristics

• A rampant grower in mild climates, a mature sweet autumn clematis can reach 30 feet in length in a single season. In cooler areas, a height of 15 feet is more common. When its cloud of blossoms appears in late summer and fall, the sight can be spectacular. Coupled with sweet fragrance and leathery, green leaves, the profuse 1-inch flowers command attention. As the season progresses, equally attractive seed heads arrive with tiny, feathery plumes. The flowers and seed heads that follow are all borne on new wood -- those vines produced during the current growing season.

Annual Maintenance

• Because only new wood carries sweet autumn's flowers, the vine should undergo thorough pruning each year. Old wood from the previous season will not produce blooms, but it will rob new growth of energy needed to form flowers. In late winter or early spring, before new growth begins, prune the vine back to approximately 12 inches above the ground. Hand pruners work best for this task. Wear protective sleeves and gloves, and sterilize your pruners prior to and between cuts to prevent the spread of disease. One way to sterilize cutting tools is to clean and then soak for five minutes in a solution of one part chlorine bleach to nine parts water. Remove all old vines and foliage, including all leaves on the ground. Only the 12 inches at the base should remain. This prepares sweet autumn for vigorous new growth that will produce blossoms in the upcoming season.

Other Concerns

• Sweet autumn's flowers and seed heads are beautiful, but that beauty comes with a price. This Japanese native , sometimes offered under the names self-seeds freely. Its prolific production results in great numbers of seeds -- and therefore plants -- being dispersed from a single vine. In many parts of the country, sweet autumn escaped from cultivation and invaded areas to the detriment of native plants. (Ref. 1, 3, Resource 1) When growing sweet clematis, care must be taken to keep the plant in check. When pruning or cleaning, bag the clippings and dispose of them in such a way that invasive seed is not unwittingly spread.

General Care

• Unlike most clematis, sweet autumn tolerates partial shade. But the vine still does best when grown with at least six hours of full sun each day. Like other clematis, it prefers cool, moist shade for its roots. Annuals or perennials planted at the vine's base provide this. Keep soils evenly moist, but never soggy. When planting, place the vine's crown about 2 inches below the soil's surface. This keeps dormant buds protected underground. In the event a rabbit damages the vine, it can come back from its roots. Sweet autumn is not susceptible to any major pests or foliar diseases. In general, it requires little care other than an annual pruning and removal of old stems and foliage each year. (Ref. 1, 2)