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Horticulture and Home Pest News
Horticulture & Home Pest News is filled with articles on current horticulture, plant care, pest management, and common household pests written by Iowa State University Extension specialists in the Departments of Entomology, Horticulture and Plant Pathology.

Summer Blooming Clematis

This article was published originally on 7/18/2007

While botanists can't seem to agree on the correct pronunciation of Clematis, they all agree that they are generally easy-to-grow. Most gardeners are familiar with the large purple-flowering varieties that bloom in late spring. But have you heard of the summer blooming types of clematis? While these types are less common, they are equally as worthy in the landscape. Vining Types. Sweet Autumn Clematis (Clematis ternifolia) is the most widely known of the summer blooming types. It is a vigorous vine that isn't appropriate for the smaller trellises commonly sold for clematis. Stronger supports are needed, but worth it! Blooming begins in August and often continues into September. The creamy-white flowers are much smaller than the spring blooming types, but what the flowers lack in size the plant makes up in shear quantity of blooms. Hundreds of the tiny flowers literally carpet the plants when blooming. In addition, the flowers are sweetly fragrant, hence the name Sweet Autumn Clematis. Plants grow and bloom well in partial shade to full sun. Durand Clematis (Clematis durandii) is another vining clematis that blooms in summer. In many ways it is the exact opposite of Sweet Autumn Clematis. The plants are much less vigorous, needing only a small trellis or nearby shrub for support. The blooms are typically bluish-lavender and up to 4 inches across. While attractive, the flowers lack the fragrance of Sweet Autumn clematis. Plants start to bloom in early summer and often continue until frost. Non-Vining Types. There are also some non-vining types of clematis that bloom in summer. These plants act more like perennials in the landscape with their upright and bush-like growth habits. Solitary clematis (Clematis integrifolia) is compact (only 18-24 inches tall and wide) with small, nodding, lavender colored flowers. Each stem is topped with a single flower where the petals reflex back a bit to reveal the creamy center. This clematis also blooms for a long time, starting in June and often continuing into August. Another non-vining type clematis is Tube Clematis (Clematis heracleifolia). Plants are larger, often growing 3 feet tall and 2 feet wide. It too has flowers that are not typical of the vining type clematis. Tube clematis flowers are as the name suggests, tube or funnel shaped. Small clusters of the lavender/blue flowers begin to appear in late summer and often continue for more than a month. Tube clematis also blooms well in partial shade. Culture. Most clematis, regardless of bloom time or habit, prefer sunny sites. A few, like Sweet Autumn and Tube Clematis, benefit from some afternoon shade. Clematis also prefer neutral to slightly alkaline soils. Since soils in Iowa tend to be in their preferred pH range, clematis make excellent and easy-to-grow additions to landscapes. Well-drained soils are, however, essential for best growth. The vining types will need pruning in early spring to remove dead wood. Wait until the buds begin to swell to tell how far back they will need to be pruned. The non-vining types will also require clean up of dead debris in late winter or early spring, preferably before the new growth emerges. Regardless of which type you choose or how you pronounce the name, there is always a clematis worthy of planting in your garden. Sweet Autumn ClematisSweet Autumn ClematisDurand Clematis FlowerDurand Clematis Flower

Year of Publication: 
2007
Issue: 
IC-497(18) -- July 18, 2007

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