Clematis

List of Clematis Types
By Larry A. Sagers
Regional Horticulturist
Utah State University Extension
Thanksgiving Point

Group A Pruning

The early-flowering clematis bloom in April and May, from buds produced the previous year. Prune these after they bloom before the end of July. This allows new flower buds to grow for the next season. Remove shoots that bloomed previously and prune vines to reduce the size or make a good branch framework. Do not cut into the woody trunks. Plants in this group include: C. alpina, C. macropetala, C. armandii, C. montana and C. chrysocoma.

Group B Pruning

Large-flowered hybrids bloom in mid-June on short stems from the previous season's growth and often rebloom with smaller flowers in late summer on new growth. Remove dead and weak stems in February or March and then cut back remaining stems to the topmost pair of large, plump green buds. This cut could be a few inches to a foot or two from the stem tips.
These plants often become bare at the base as they mature. Underplant them to help conceal the stems. You can often force a flush of new growth from the base by cutting the vine back to 18 inches immediately after the flush of bloom in June. Plants in this group include: 'Nelly Moser,' 'Miss Bateman,' 'Lasurstern,' 'Duchess of Edinburgh,' 'Mrs. Cholmondeley' and others.

Group C Pruning

Late-flowering clematis produce flowers on the last two to three feet of this season's growth. Some types begin blooming in mid-June and continue into fall. This group is easiest to prune since you do not need to maintain old growth. Cut each stem two to three feet long in February or March. This removes some good stems and buds but the plant still blooms well.
Eventually the length of the bare stem at the base will increase as the vine matures. Plants in this group include: C. viticella, C. flammula, C. tangutica, C. x jackmanii, C. maximowicziana, 'Perle d'Azur,' 'Royal Velours,' 'Duchess of Albany' and others.

Selected Species and Cultivars
Species and Small-flowered Types

C. alpina-6 to 8 feet in height, blooms April-May. Flowers on long stalks, 1.5 inch, nodding, bell-shaped flowers, that are lavender or purple-blue in color. Seed heads are gray, fluffy balls holding until winter. Hardy, fool-proof plant. Group A pruning.
C. alpina 'Candy'-6 to 8 feet in height, blooms April-May. Blooms have light pink outer sepals, pastel pink inner; stamens are green. Group A pruning.
C. armandii-15 to 30 feet in height, blooms April-May. Two-inch diameter blooms, creamy white in large axillary clusters; has a strong vanilla scent in warm weather. Strong, vigorous grower. Group A pruning; can cut to base to rejuvenate vine.
C. chrysocoma-20 feet in height, blooms May-June. Long stalked flowers 1.5 to 2 inches in diameter occur in axillary clusters; pale mauve-pink with creamy stamens. Some bloom occurs in late summer. New foliage is bronze-red. Group A pruning.
C. flammula-15 to 20 feet in height, blooms August-September. Flowers occur in terminal clusters in great masses, are 1 to 1.5 inches in diameter, and white. They are grown from seed so growth can be variable. Group C pruning.
C. macropetala-To 15 feet in height, blooms April-May. Flowers are double, nodding bells, 2.5 to 3 inches in diameter, pale blue with purple shading. Seed heads last into winter. Foliage is neat and attractive; plants prefer cooler, shady location. 'Snowbird' is pure white with a hint of green on inside of bloom. Group A pruning.
C. maximowicziana-To 30 feet in height, blooms in September. Flowers are 1.5 inches in diameter, cruciform, white. Very vigorous grower. Group C pruning.
C. montana-20 to 30 feet in height, blooms May-June. Flowers are white, 2 to 2.5 inches in diameter and some cultivars have a vanilla scent. One of the easiest to grow and propagate; very vigorous. Group A pruning.
C. tangutica-10 to 15 feet in height, blooms July-October. Most common yellow-flowered form. Flowers are 1 to 1.5 inches in length and nod on a long stalk, singly or three to a stem. Seed heads are spectacular, lasting into winter. Group C pruning.
C. viticella-10 to 12 feet in height, blooms July-September. Flowers slightly nod, are 1.5 to 2.5 inches borne singly or in clusters on a slender stalk; rich deep purple with small green stamens. Vigorous and easy to grow. Group C pruning. 'Abundance' is bright mauve-pink, red with deeper red veins and creamy green stamens. 'Etoile Violette' has slightly larger blooms that are deep purple with creamy-yellow stamens.

Large-flowered Hybrids

'Barbara Jackman'-8 feet in height, flowers May-June. Vigorous, bushy plant. Flowers are 4 inches in diameter, deep purplish-blue with bright magenta bar and large, creamy-yellow stamens. Fades to mauve-blue. Group B pruning.
'Comtesse de Bouchard'-6 to 8 feet in height, flowers July-August. Easy to grow, prolific bloomer; a good plant for smaller spaces. Flowers are 4 to 6 inches in diameter, pink with creamy stamens. Group C pruning.
'Hagley Hybrid'-8 feet in height, flowers June-September. Flowers are 4 inches in diameter, pale mauve pink, fading to a washed out pink. Stamen filaments are white and anthers purple-red. Vigorous grower. Group B/C pruning.
C. x jackmanii-8 to 10 feet in height, blooms July-August. Flowers are 4 to 5 inches in diameter and deep bluish-purple. Free flowering. Group B pruning.
'Marie Boisselot'-8 to 12 feet in height, flowers June-September. Opening flower buds are flushed with lilac-pink, flowers are 8 inches in diameter, white with creamy stamens. Strong grower. Group B pruning.
'Mrs. Cholmondeley'-20 feet in height, flowers May-October. A "foolproof" plant. Blooms are light lavender blue, paler along the midrib, filaments white and anthers brown. Group B/C pruning.
'Nelly Moser'-8 to 10 feet in height, flowers May-June and September. Flowers are 8 inches in diameter, pale rosy mauve with a central carmine colored midrib; dark maroon anthers. Flowers will fade badly in full sun; provide some shade for this plant. Group B pruning.
'Niobe'-8 feet in height, flowers June-September. Cup shaped bloom opens dark ruby-red then turns to bright ruby red with cream stamen. First flowers are 6 inches in diameter, later ones 4 inches in diameter. Moderate grower with some bloom throughout the season. Group B/C pruning.
'Perle d'Azur'-16 feet in height. Flowers continuously early summer to mid-autumn. Blooms are 4 to 6 inches in diameter, sky blue with green stamens. Group B pruning.
'Vyvyan Pennell'-8 feet in height. Flowers June and September. Flowers are 6 to 8 inches in diameter, double at first, single later. Deep violet-blue blooms suffused with purple-red; golden stamens. Group B

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