Selecting and Caring for Clematis

Clematis are lovely and useful plants for the garden. We offer 3 different types: the familiar twining vines, and the lesser-known shrubby and trailing forms.

• The vines are available as the popular large-flowered hybrids as well as small-flowered hybrids and species. They are typically planted to grow up a lamppost or trellis, but are also attractive when allowed to clamber up a tree or shrub.


• Shrubby clematis are commonly used in the perennial garden, where they offer late-season color. Most have a rather lazy habit, and can be supported using neighboring plants or stakes and twine.


• Trailing clematis are the least known, and are typically either tied to a support such as a mailbox or a lamppost, or given the chance to trail freely through a garden.

Clematis are generally easy to grow, providing that certain conditions are met. First, they usually require at least 1/2 day of sun. Afternoon shade will benefit the blossoms of many clematis, especially those with prominent contrasting “bars” in the flowers. A deep, fertile soil is also needed, which can be prepared by digging a hole at least the size of a 5-gallon bucket, and discarding any poor soil. To the better soil, add an equal quantity of organic matter, such as Coast of Maine™ compost. One-half cup or so each of ground limestone and an organic fertilizer such as Pro-Gro™ is also beneficial. Blend all the ingredients, dump the amended soil back into the hole, and plant the clematis carefully, taking care not to damage brittle stems when securing to a trellis or other support. Good mulch helps to keep the soil cool and moist. Water well, and maintain it as you would any new planting.

Large-flowered clematis are susceptible to a disease known as Clematis Wilt. This disease remains a mystery to gardeners and scientists alike, for it is unknown if it is caused by a fungus, wounding of the stems caused by windy conditions or mishandling, or a phenomenon of the plant being unable to provide enough water to the stems during stressful weather. In any event, it is characterized by a sudden wilting of the leaves starting at the tips of the stems, and progressing downward. Benomyl™, a commercial fungicide, is commonly used to counteract it. Pruning the stems down to healthy growth will often stop the disease, and new stems will usually arise from buds hidden below ground. Clematis Wilt rarely, if ever, will kill clematis; at most flowering may be disappointingly delayed. Please note that The Mixed Border Nursery will not replace any clematis that has been affected by Clematis Wilt.

Pruning clematis is often confusing to the uninitiated. However, once you understand that you will not kill clematis either by pruning it according to the wrong method, or by not pruning it at all, it becomes much easier. Clematis are grouped according to the way they flower, and this governs how they ought to be pruned. If you are unsure what type you have in your garden, observe its flowering habits for a season, and follow the recommendations that most closely match what you have. Except for Group 1 types, all may be cut back severely in spring with at worst a temporary effect on flowering.


Group 1:
These plants flower early on old stems and generally do not need to be pruned, except to remove dead or damaged stems. If pruning is necessary to control growth, cut stems back after flowering.

Examples:
Clematis alpina and varieties
Clematis macrophylla and varieties

Group 2:
These also flower on old wood, but a later flush of flowers happens in late summer on new growth. In early spring before buds have opened, prune out any dead or weak stems, and cut back remaining stems to a pair of buds. The lower down the stems you cut, the more flowering will be delayed. Cutting the stems by half is a good rule of thumb.

Examples:

Clematis ‘Amethyst Beauty’	C. ‘Arctic Queen’	C. ‘Asao’
C. ‘Bee’s Jubilee’	C. ‘Belle of Woking’	C. ‘Blue Ravine’
C. ‘Carnaby’	C. ‘Crystal Fountain’	C. ‘Diana’s Delight’
C. ‘Duchess of Edinburgh’	C. ‘Elsa Spath’	C. ‘Empress’
C. ‘Franziska Maria’	C. ‘Guernsey Cream’	C. ‘Henryi’
C. ‘Isago’	C. ‘Josephine’	C. lanuginosa ‘Candida’
C. ‘Nelly Moser’	C. ‘Niobe’***	C. ‘Perrin’s Pride’
C. ‘Piliu’	C. ‘Proteus’	C. ‘Rebecca’
C. Rhapsody’***	C. ‘Rosemoor’	C. ‘Silver Moon’
C. ‘Sunset’***	C. ‘Sugar Candy’	C. ‘Veronica’s Choice’
C. ‘Vino’	C. ‘Vyvyan Parnell’	C. ‘Warsaw Nike’

Group 3:
Flowers are produced on new stems each year, so vines can be cut down to a pair of buds near the ground in late winter or early spring.
Examples:

Clematis ‘Alionushka’	C. ‘Arabella’	C. ‘Barbara Harrington’
C. ‘Comtesse de Bouchard’	C. ‘Hagley Hybrid’	C. heracleifolia and hybrids: ‘Mrs. Robert Brydon’
C. integrifolia and hybrids	C. ‘Jackmannii Superba’	C. ‘Niobe’***
C. ‘Perle D’Azur’	C. ‘Petite Faucon’	C. recta and varieties
C. ‘Rhapsody’***	C. ‘Roguchi’	C. ‘Rouge Cardinal’
C. tangutica and varieties	C. ternifolia (aka C. paniculata)	C. texensis ‘Duchess of Albany’, ‘Odoriba’, ‘Pagoda’
C. ‘Ville de Lyon’
C. viticella and hybrids:
C. v. ‘Mrs. Betty Corning’	C. v. ‘Etoile Violette’	C. v. ‘Kermesina’
C. v. ‘Polish Spirit’	C. v. ‘Purpurea Plena Elegans’

***Note: these varieties may be pruned according to either Group 2 or Group 3.
Photos courtesy of Donahues Clematis

Guide to Successful Planting and Care

Before you plant...
Can't plant your purchases right away? Relax! Plants in containers will remain in good health for a long time. Just make sure that they are watered regularly so that they don't dry out before you are ready to plant them. A slightly shady spot will be beneficial. Balled-and-burlapped (B&B) plants may also be treated the same, except that a mulch around the roots will slow down water loss and keep the roots cool until planting. If you have any questions after reading this planting guide, please give us a call at 603-882-5538.

Soil preparation...
Adding at least a couple of inches of organic matter such as Coast of Maine^tm compost over the surface of the bed, along with perhaps a dusting of powdered limestone and a sprinkling of a good organic fertilizer, such as Pro Gro^tm. Then turn them all into the soil to a depth of at least 6 inches. Rake smooth, and the planting will be easy. Unless adding a plant to an existing bed, don't cheat by just amending the soil removed from the planting hole, for the roots need to be encouraged to be developed beyond it. This is especially true when planting trees and shrubs. Many studies have shown that amending the soil only within the planting hole actually inhibits root development beyond it. The roots need to grow into the surrounding soil, and the sooner that happens, the faster and better the plant will become established.

Note: plants that are said to require "good drainage" usually need some sand added to the soil, rather than organic matter.


Drawing by Tom Strangfeld. Used with permission.

Planting...
Dig a hole at least twice as wide as the rootball; wider is better, especially for trees and shrubs, but no deeper than the height of the root ball. (Exceptions would be roses, clematis, and peonies: these will generally do best in a hole dug about the same size as a 5 gallon bucket, with richly amended soil). If the soil has been prepared as earlier explained, no additives are needed.

After digging the hole, remove a potted plant from its pot and examine the roots: any that are encircling the soil should be gently pulled apart with fingers. More substantial roots that encircle the pot can be cut or teased away with an old knife, trowel, or spade. Set the plant in place, and after making sure that it is facing the right direction and is plumb, fill the hole with soil level with the top of the root ball but not covering it. Press the soil firmly with your hands, and add more if needed to be level with the top of the root ball. (See illustration.) Water well.

Balled and burlapped plants are installed the same way, except that any twine should be cut off after the plant is set in the hole, and the burlap loosened and gently cut away with a utility knife. Wire baskets should not be removed, as they help keep the root ball intact. (See illustration.)

Then, mulch the soil with a 2-inch layer of shredded bark or other material of your choice. Please do not mound the mulch up around the stems.

Mulches...
Organic mulches of many sorts are recommended: shredded bark; buckwheat or cocoa hulls; compost; shredded leaves; and even pine needles (the answer is no, they don't make the soil more acidic, but you can add a little extra lime if you aren't sure). All mulches add valuable organic matter to the soil as they decompose, so top-dress as needed. Avoid mulch volcanoes around trees! Pea stone makes good mulch for plants that prefer dry, gravelly soil, such as those found in rock gardens.


Drawing by UMass Extension. Used with permission.

Watering...
Lawn irrigation systems are not suitable for watering trees, shrubs and perennials. Consider installing a reliable, waterconserving drip irrigation system. Newly installed plants should not be allowed to completely dry out. Watering depends upon many factors: season, water needs of plant, exposure to sun or wind, weather, etc. Check the soil regularly for dryness. Dry soil falls apart when handling it; moist soil feels cool and retains its shape somewhat when squeezed. Water deeply rather than shallowly. Do not depend upon natural rainfall when establishing plants!

Aftercare...
Fertilizer, whether synthetic or organic, may be applied in the spring or fall. Organic forms are best, as they feed the soil rather than the plant, and release their nutrients slowly. We recommend Pro Gro^tm.You may choose a specialty fertilizer, or an all-purpose 5-10-5 or close equivalent. Adding a thin layer of compost each fall contributes valuable organic matter as well as a modicum of nutrients, which feed the soil. You'll see a difference the next year in your garden.

Winter Protection...
Perennials benefit from a light mulch applied in late fall, after the soil has frozen. Salt marsh hay is the best, because it contains no weed seeds, and lasts for a few years if dried and properly stored the next spring. Check The Mixed Border Nursery and Gardens for availability. Otherwise, use evergreen boughs, such as recycled Christmas trees or straw. Uncover gradually in late March or very early April, after the snow has melted.

Trees and shrubs usually need no winter protection, except for evergreens, which often benefit from screening out the winter sun and wind for a year or two after planting. A roll of burlap works well. Various wraps applied to the trunks of trees are usually not recommended.

Please remember that gardening involves nature, and weather cycles can affect the winter survivability of plants in the landscape, despite our best efforts.

Pruning...
Pruning is a subject unto itself. Suffice to say that most people do not prune plants properly; plants are often sheared into shapes ranging from golf balls and hockey pucks to chicken nuggets. A better method is to selectively thin out branches that have become too long, or too dense. Restraint, and a good book on pruning is helpful, or call us at The Mixed Border Nursery and Gardens to have us do the pruning the right way, at the right time.

Problems?...
Although we strive to sell only pest-resistant plants, occasionally insects or disease affect plants. Please be sure to identify the problem before treatment to avoid possible environmental harm. Call us, or contact your county Cooperative Extension Service office. In Hillsborough County, NH, the contact number is 1-877-398-4769 or UNH Cooperative Extension Service.

Our Guarantee...
We guarantee that our plants are true to name and in healthy condition when they leave the nursery, and will not knowingly sell any otherwise. If you have a problem with one of our plants, please let us know about it as soon as possible. Most experienced gardeners realize that losing plants occasionally is part of gardening. Sometimes plants perish due to unusual weather, improper planting or aftercare, or placement in the wrong location. Rarely will plants fail due to insects and disease. The Mixed Border Nursery and Gardens will not be liable for any such losses. If a plant fails to survive within 30 days of purchase, we will provide, at our discretion, full replacement or store credit based on the purchase price. Responsibility for losses beyond 30 days will be shared with the gardener, and we will offer a 50% store credit based on the purchase price of the plant. We cannot extend our policy beyond 90 days from the date of purchase or beyond the year of purchase, whichever is sooner. Plants purchased on sale are excluded from any warranty. All returns must be accompanied by the original sales receipt and plant in question. (Effective 6/1/06) Plants installed by The Mixed Border will be warranted for a period of one year following the date of planting. Certain conditions apply.