Today’s Mastering Gardening Series is about Clematis care and pruning. Clematis is one of my favorite climbing vines. If you don’t have a trellis Clematis is great planted at the base of a small tree or shrub.
like a clematis
she withers after August
is reborn next May
Few plants can rival the brilliant splendor of a Clematis in bloom. Treated properly they will grown vigorously and quickly to cover a trellis in a single season. Clematis are available in many colors, from pure white to reds, pinks, magenta, yellow, purple and blue. Some produce huge blossoms, often 4-5″ across, such as such as ruby red as Ernest Markham, white like Henry and deep purple of Jackmanii are just a few examples.
Clematis varieties range in hardiness, but many are hardy to zone 3. Grow a shorter and non-climbing types through shrub Roses and small trees. Cover an arbor or a trellis with the taller varieties.
THE CARE OF CLEMATIS
Many are under the impression that Clematis are hard to grow, but Clematis is easy to grow as long as you provide them:
Light/Watering: In general, these lush vines like at least six hours of sun; some varieties are adapted to partial shade and ALL benefit from afternoon shade in the South. Clematis prefers their roots to be cool (their don’t like their feet to get hot) so plant annuals or shallow-rooted perennials around, or lay flat stones at their base. Regular watering is desirable, especially during seasonal dry periods. Clematis are deep-rooted, so water thoroughly.
Fertilizer/Soil and pH: Clematis is at its best in rich soils with good drainage. It prefers a neutral soil, so check pH and add lime if needed. Dig a generous hole and amend soil as yours requires, plant the crown of your plant 3-4 inches below the soil surface; this will protect dormant buds that will provide new growth if the existing stem(s) are injured.
Clematis likes to be supported (don’t we all), up a trellis, tree or shrub (roses, etc). Clematis is a heavy feeder; supply a low nitrogen fertilizer such as 5-10-10 in spring, when the buds are about 2 inches long. Alternate feedings every 4 to 6 weeks with a balanced 10-10-10 fertilizer. Continue this alternate feeding until the end of the growing season.
TIP: Clematis like to be supported right away or they will languish.
Pests/Diseases: Clematis are fairly free from disease and major pests, but there are a couple worth mentioning.
Clematis wilt is a fungal disease where part of the plant will suddenly turn black with purple veins and have a wilted look. It usually appears just as the flowering buds begin to open with one of more stems being affected. Cut the WHOLE stem to the ground and treat with a fungicide (if you use chemicals) such as benomyl. It is very seldom life threatening and the Clematis will quickly regrow.
Note: if leaves are more brown (like below) and NOT black the problem is more likely a broken stem or damaged stem. This can be caused by wind, hoeing, slugs or careless handling.
Pest are usually only three, slugs, earwigs and grasshoppers. Slugs prefer to attach young shoots, so if desired use slug bait early in season. Earwigs usually attack in early summer and can turn the bloom of late flowering clematis into lacework over night. Grasshoppers are too mobile to be any effective control.
TIP: Handle the plants gently because physical injury to the stems can cause them to wilt and die.
Transplanting: Young vines may be moved with plenty of soil as long as they are watered religiously. Depending on variety, cut back lightly or severely before moving in early spring.
When they bloom determines when to prune
Why prune anyways: if left unpruned, clematis vines become overloaded with decrepit stems that produce few flowers. Pruning clematis vines stimulates new growth, which increases the number of flowers, encourages flowers at a level where you can best enjoy them, and takes weight off the plant to keep it from toppling over.
TIP: Flowering tends to decline on stems that are four or more years old. Use Renewal pruning to “prune out” very old stems periodically in early spring. This helps produce more compact plants with flowers closer to eye level.
TIP: Rejuvenate old plants by cutting them back severely, to about 18in. Wait until after the first flush of bloom to perform the surgery.
CLEMATIS ARE DIVIDED INTO “PRUNING GROUPS”
Pruning: Dead or damaged stems may be removed at any time.
If you know what variety of cultivar your Clematis is than you can prune according to whether it is Group A, B, or C
TIP: If you do not know which group your Clematis is in then try the following.
“if it flowers before July, it blooms on one year old wood (wood produced last season) treat as Group A or B. Mid summering flowering types generally bloom on vines produced this year (new wood) and belong to Group C”
Group A: Flowers only on growth produced the previous season (on old wood). Bloom on old wood and require NO pruning. But cut out weak and dead stems as soon as finishes blooming in May and June. Pruning later than June or severely pruning will result in fewer blooms next Spring.
Varieties included are Clematis alpina ‘Stolwijk Gold’ and Clematis montana ‘Mayleen’, C. macropetala (Bluebird, Rosy O’Grady), Apple Blossom, Constance, Pamela Jackman, Blue Bird, Ruby, Willy, Jan Lindmark, Markham’s Pink, White Swan, Maidwell Hall
Group A Pruning
Group B: The group contains most of the large flowered hybrids. Some bloom twice in a year (bloom first on old wood and then again on new). Stems should be tied back into their supports when pruned.
Group B (1) are the types that flower on wood that has been hardened by the previous season’s (old wood) growth. Normal blooming patterns for this group consist of heavy flush of flowers in May-June (old wood) and followed by a second smaller flush of blooms in September (new wood or current seasons wood).
Pruning should be light, primarily to remove dead or weak stems. Remaining stems should be shortened back to just above the top pair of fat green buds from which flowering shoots will developed. It is best to wait till late Spring to see if vines are indeed dead before pruning since new sprouts can emerge from some very dead looking vines.
**Suggestion – a second bloom is increased if the seed heads are removed right after the first blooms drop their petals.
Examples: Nelly Moser, Moonlight, Bees Jublilee, Blue Ravine, Capitaine Thuilleaux, Alice Fisk, Barbara Dibley, Beauty of Worcester, Belle of Working, Countess of Lovelace, Duchess of Edinburgh, H.F. Young, Margaret Wood, Elsa Spath, Guernsey Cream, Miss Bateman, Lady Caroline Nevell, Mrs. George Jackman, Piccadilly, Proteus, Royalty, and many more
Group B (2) This blooms simultaneously on last year’s growth and the current seasons growth. These bloom typcially from June to September continuously.
Pruning these varieties can be treated as either Group B (1) or C. If planted alone than Group C pruning regime every second year is recommended.
In Canada you should get two flushes of flowers if you just clean out old wood and prune to a bud 3′ to 4′ above ground. Prune as soon as possible after flowering. If winter kill is a problem then you might only get one late season flush of flowers
Examples: The President Silver Moon, Crimson ‘Star, Henryi, John Paul II, Lincoln Star, Bell Nantaise, Crimson King, Edith, Jackmanii Alba, Jackmanii Rubra, Guiding Star, Crimson King, C. W. Dowman, Fair Rosamund, Horn of Plenty, Joan Picton, John Warren, Kathleen Wheeler, Ramona, Sealland Gem, Twilight, Warsaw Nike, William Kennet and any more
Group B Pruning
Group C: This group blooms only on current years growth (new wood). Booming begins in early summer and continues through to fall. Prune hard in Spring. Cut plants back in May to two strong sets of buds (4) on each stem as close to the ground as possible. This will provide a plant with blooms that start near ground level and continue to top of the plant.
**This group is ideal for growing through shrubs as all old growth is removed annually.
Examples: All Clematis viticellas (Blue Angel, Blue Bell, Minuet, Polish Spirit, Purpurea Plena Elegans, Rubra, Royal Velours) C. integrifolia, late flowering large varieties such as Jackmanii, Hagley hybrid, Ernest Markham, Comtese de Bouchard, Perle d’Azure, Polish Spirit and Purpurea Plena Elegans, Allanah, Gyspy Queen, Lady Betty Balford, Margaret Koster, Pink Fantasy, Star of India, Rouge Cardinal and many more.
Group C Pruning
End of Season Care: Plants may be mulched, but take care to keep mulch material away from the crowns and stems of the plants. Make sure that the vines of Group A and B plants are tied securely to supports to withstand winter winds.
TIP: if you want a simple, “no fuss” pruning, use Group C for all.
IF CALENDAR CARE IS EASIER FOR YOU TO FOLLOW
Early Spring: Fertilize with 5-10-10 when new growth reaches two inches. If you need to move a plant, transplant young vines now. Wait until new growth appears before removing dead or damaged stems and before pruning as required by variety:
– leave Group A Clematis alone
– prune Group B plants lightly to shape and remove weak growth;
– cut Group C varieties back to 12 inches above the ground, or higher if you desire taller vines.
****If this is the first spring after planting, prune stems of all varieties down to the lowest pair of healthy buds to encourage strong growth and new stems.
Mid-Spring: Continue feeding every month, alternating 5-10-10 with 10-10-10. Plant annuals at base of plants if unprotected by flat stones to allow for a cool root zone. Gently tie vines to supports as they grow.
Late Spring: Mulch if desired but keep material away from crowns and stems. Water thoroughly if season is dry. Cultivate around vines with care as physical injury will cause wilting and death of injured stems. Continue to guide new growth by tying to supports as needed.
Lightly prune Group A Clematis immediately after flowering to shape the vines if needed.
Summer: Watch for signs of fungal wilt and remove and destroy affected plant parts if it occurs, then sterilize pruners with bleach solution.
Group B Clematis may be pruned back by one-half after main flush of bloom to encourage strong growth and new flowers. Continue to water if conditions indicate.
Fall: Check to be certain that the vines of Group I and II varieties are tied securely to supports to withstand winter wind and snow. Mulch if desired, keeping material away from the crown. If the season is dry, water well and deeply.
I hope this helps you to keep you Clematis healthy and happy!
Feel free to ask any questions you might have.