Vines and Climbers: Pruning Plants That Ascend
Vines are plants with long, long stems that make their way up in the world by clinging to or twining around a support. As long as there is something sturdy to mount, true vines can do it alone, or with minimal help. There are a handful of other plants that we call vines—Bougainvillea and climbing roses (Rosa) are two popular examples—that neither cling nor twine and can't ascend without help. Since they also want to be head and shoulders above their fellows, you must tie them to or drape them over a support.
As with other woody plants, the time and energy you'll spend pruning vines has much to do with the plant you select and the spot in which you place it. You'll save yourself a good deal of anguish if you pick a vine that can live comfortably in the space you have. Old wisterias can produce primary stems the size of tree trunks and have been known to pry off drainpipes and gutters. Even my tropical wax plant (Hoya carnosa)—which hangs indoors and receives far less light than it needs—has managed to creep under the molding of the window, emerge on the other side, and now threatens to escape to the outdoors through a tiny tear in the screen.
Most perennial vines, such as Clematis 'Comtesse de Bouchaud', need regular pruning to keep them healthy, productive, and under control. Photograph: Alan and Linda Detrick
How vines grow affects how much pruning they may need. Among the most intrepid are species that climb by using aerial rootlets and species like Virginia creeper (Parthenocissus quinquefolia) that have holdfasts, little suction cups that grab onto walls and other surfaces. Also exuberant (and sometimes invasive) are many vines that twine, such as Wisteria, bittersweet (Celastrus scandens), and honeysuckles (Lonicera). Somewhat less rampant are the vines that ascend by using tendrils, such as Clematis, grape (Vitis), and passionflower (Passiflora). But only somewhat.
Unlike many shrubs and trees that do well without ever being thinned or cut back, even vines grown in sizable settings may require regular pruning to keep them healthy, productive, attractive, and under control. Many vines just don't know when to quit—or in which direction to grow. They must be taken in hand early on or they will be collapsing trellises, pulling down fences, and obscuring windows and doors.
Once vines have developed adequate roots, most just keep on growing above ground. To keep a vigorous climber healthy, you must do the following:
- Remove any dead, damaged, diseased, or unproductive stems.
- Remove overly tangled stems.
- Remove errant stems, especially those growing away from the support.
- Direct its growth.
- Limit its growth.
Reducing a vine's mass not only ensures that your fence won't collapse, it also allows light and air to reach the plant's interior. Don't forget, though, that pruning doesn't just reduce mass: It can increase it. Heading back stems encourages new growth.
If you've purchased a container-grown vine—standard nursery fare these days—no pruning is mandatory at planting time, especially with evergreen vines. But heading back, which will encourage new growth, may be a good idea if your plant has long, spindly shoots with few leaves or only a single stem. Bare-root plants should be headed back by no more than a quarter before they are planted to allow the vine to balance its growth below and above ground. Be sure to cut out any damaged or dead roots and stems, or stems that have minds of their own and appear determined to grow into the neighbor's yard rather than up your trellis.
When to prune Clematis depends on what type it is. Prune Clematis montana var. rubens, left, after flowering. Prune Clematis 'General Sikorski', right, lightly in winter. Photograph: David Cavagnaro
Vines in their first or second year tend to sprout and elongate stems more than produce leaves and flowers. Pinching back shoot ends helps balance their growth. Also, woody vines tend to flower more generously on shoots that are horizontal rather than vertical, so keep that in mind as you direct and shape your climbers. Twining vines especially grow from upper buds and tend to lose their lower leaves. They may need severe heading back to promote foliage near the ground. If you want a compact vine, head back stems throughout the growing season; if you want a vine to ramble, keep your pruning shears in their scabbard.
The guidelines for pruning mature vines are similar to those for pruning deciduous shrubs. Species grown for their foliage can be pruned throughout the garden season, but early spring before leaves appear puts the least stress on the plant. Vines that flower in summer and fall on the current year's growth, such as honeysuckles (Lonicera), should be pruned in late winter or early spring. That schedule gives the plant time to produce new shoots and flowers. Prune vines that flower early in the garden season on shoots produced the previous year—jasmines (Jasminum) and Wisteria are two—immediately after their flowers fade. Most hardy vines fall into this category.
Except...like all general rules, there are exceptions, the most important of which concerns vines that produce ornamental or edible fruits. Even if postflowering pruning is called for, wait until spring, or the fruit crop will be lost.
When you prune, be sure to do the following:
- Cut to healthy wood if removing dead, diseased, or damaged growth.
- Cut back to a lateral shoot or bud.
- Cut to a bud or stem that is pointing in the direction you want the vine to go.
- Cut cleanly and don't leave a stub, which is an invitation to bugs and diseases.
Pruning mature vines can be difficult, because their long stems become tangled. Don't be tempted to yank. Instead, prune one stem section at a time until you've cut out all you want to remove.
A Vine-by-Vine Guide to Pruning
Some vines don't have to be pruned every year, but all vines need basic care: Remove dead, damaged, and diseased stems; stems that are tangled or head in the wrong direction; stems that are weak or unproductive; unwanted suckers; and spent flowers. Beyond those cuts, the general goal when pruning vines is to keep them healthy, vigorous, and productive, and to help them follow their natural inclinations at the same time they fulfill your needs.
Actinidia species, kiwi, silver vine. Flower on new wood. Do maintenance pruning—to train or control—on silver vine (Actinidia polygama), variegated kiwi vine (A. kolomikta), and other ornamental actinidias after they flower. Save severe or renewal pruning for late winter to early spring when the vine is dormant.
Aristolochia macrophylla, Dutchman's pipe, pipevine. Dutchman's pipe flowers on old wood, but it is grown for its foliage and can be pruned anytime to remove tangles and errant shoots. Save renewal pruning for late winter to early spring when the vine is dormant, then cut oldest stems to six inches.
Bignonia capreolata, crossvine, quartervine, trumpet flower. Flowers on new wood. Prune to remove weak, overgrown, or errant shoots in late winter to early spring; head back shoots to encourage new growth. Needs minimal pruning.
Pruning mature vines such as this Bougainvillea can be difficult because their long stems become tangled. Don't be tempted to yank. Instead prune stems section by section. Photograph: Jerry Pavia
Bougainvillea species, bougainvilleas, paper flowers. Most bougainvilleas flower intermittently throughout the year on new growth, with the heaviest bloom cycles (followed by a rest cycle) coming in spring and fall. Prune after flowering ends. Remove dead, tangled, and errant wood and suckers; head back long stems to encourage new flower buds.
Campsis radicans, trumpet creeper, trumpet vine, cow-itch. Flowers on new growth. Head back stems in late winter to early spring to control growth and encourage branching. Remove suckers and root-prune to discourage underground runners. Cut stems to ten inches to renew.
Celastrus scandens, American bittersweet. Blooms on new wood. Prune in late winter to early spring. Remove suckers, tangled and weak stems, and stems that have fruited; head back last year's growth; pinch shoot tips in summer to encourage branching. Do not confuse this native species with Celastrus orbiculatus, oriental bittersweet, which is invasive.
Clematis, clematis. See "Clematis: The Queen of Vines."
Cocculus carolinus, Carolina moonseed, coral beads. Flowers on new wood; prune as needed in early spring.
Ficus pumila, creeping fig, climbing fig. Remove older stems in late winter or early spring to promote immature foliage form. Pinch stem ends to promote branching. Needs little pruning.
Gelsemium sempervirens, Carolina jessamine, evening trumpet flower. Flowers on old wood. Head back lateral shoots, remove dead stems, and prune to shape after flowering ends.
Humulus lupulus, common hop. Flowers on new growth. Commercial growers cut their hop vines to the ground in late summer to harvest the cones. Hop vines grown for ornament should be cut to the ground in late winter to early spring. Root-prune to control underground runners.
Hydrangea petiolaris, climbing hydrangea. Flowers on new wood. Head back in early spring; remove stems that have pulled away from their support. Prune hard to renew.
Ipomoea species, cypress vine, morning glory. Ipomoea species, including morning glory (I. tricolor) and moonflower (I. alba), the p.m. version of the morning glory, flower on new wood. Cut vines to the ground in late winter to early spring in zones where they are perennial.
Jasminum nudiflorum, winter jasmine. Flowers on old wood; prune immediately after blooms fade. Winter jasmine, primrose jasmine (Jasminum mesnyi), and common, or poet's, jasmine (J. officinale) need minimal pruning.
Lonicera, honeysuckle. Prune Henry's honeysuckle (Lonicera henryi), trumpet honeysuckle (L. sempervirens), woodbine (L. periclymenum), and trumpet honeysuckle cultivars (L. x brownii) in late winter to early spring to control growth; remove weak shoots; head back long stems. Renew old vines by cutting a third of oldest stems to the ground. Japanese honeysuckle (L. japonica) and its cultivars are extremely invasive and not recommended.
Mandevilla splendens, mandevilla. Flowers throughout the growing season on old wood; little or no pruning necessary.
Menispermum canadense, Canada moonseed, yellow parilla. Flowers on new wood. Postpone pruning until spring to preserve ornamental fruits. Root-prune to control underground suckers.
Parthenocissus species. Most Parthenocissus species, including Virginia creeper, or woodbine (P. quinquefolia), and Boston ivy (P. tricuspidata), need pruning only to control or direct their growth. Grown for their leaves, they can be shaped throughout the garden season; wait until late winter to early spring to do radical pruning.
Incense passionflower, Passiflora 'Incense', blooms on new wood and needs only moderate pruning unless it's grown for fruit production. Photograph: Alan and Linda Detrick
Passiflora species, passionflowers. Bloom on new growth; remove tangled and unproductive stems in spring. Need only moderate pruning unless grown for fruit production.
Periploca graeca, silkvine. Flowers on new wood. Little pruning needed; head back in spring to stimulate and direct growth.
Rosa species and cultivars, climbing and rambling roses. See "Roses."
Schisandra species. Schisandra species, such as Chinese magnolia vine (S. chinensis) and bay star vine (S. coccinea), flower in spring on old wood, but postpone pruning until late winter or early spring to preserve their ornamental beaded fruits.
Schizophragma species, hydrangea vine. Both Japanese hydrangea vine (Schizophragma hydrangeoides) and S. integrifolium flower on new wood. Prune in early spring; little pruning is needed.
Vitis species, grapes. Flower on new growth. Grape species traditionally are pruned in late winter. Ornamental grapes, such as V. vinifera 'Brandt', V. vinifera 'Purpurea', and V. coignetiae do not require the careful and severe pruning that is needed when growing grapes for their fruits.
Wisteria species, wisteria. Native wisterias, including American wisteria (W. frutescens) and Kentucky wisteria (W. macrostachya), are less vigorous and showy than Asian species, which are invasive. They flower on short, leafy shoots, or pedicels, that arise from buds on the previous year's wood. To encourage flowering, head back stems after blooms have faded; if necessary, head back a second time in late winter, leaving at least three or four buds. Train shoots to establish a framework or increase vine height; head back once the desired height and width have been achieved. Old plants can be renewed by severe pruning, almost to the ground.