The Seed is the horticultural magazine of the Nebraska Statewide Arboretum. It is published twice a year for the members of the Arboretum. This issue was written by Karma Larsen. Copyright 2001. For a full version of this publication with visuals, photographs, charts, landscape designs, etc. call 402-472-2971.

The Seed, Fall 2001

Vines and Climbers

     Why vines? Maybe it's simply that we prefer green.
     There are plenty of structures in our lives… houses, garages, fences, clotheslines, mailboxes, compost bins. Vines meld and soften all the hard edges, blurring the boundaries between garden and fence and gutter and house, extending green far into places where no garden exists.
     They can provide quick privacy, screen buildings or parking lots, give shade-some of them within just a month or two, define and separate distinct areas in a garden. Areas that are awkwardly shaped can be softened with vines. Many vines have beautiful blossoms and good fall color; a few are evergreen in Nebraska.
     Though vines tend to be used as climbers, they also work well as groundcovers, twisting around rocks and through low-growing perennials and shrubs, adding dramatic bursts of color when blooming. Like any groundcover plant, they function much like a mulch, shading the roots of perennials and competing with weeds.
     Vines extend themselves in a variety of ways and the differences are important in deciding which plant to put in a particular spot or to climb an existing structure.
     Twining vines like honeysuckle and morning glory wrap around their support so they require fairly thin surfaces like wire, string, netting, small poles and slats.
     Clasping vines like clematis, grape and porcelain berry also require thin wire or netting for support but in their case the entire stem doesn't spiral but has tendrils, specialized stems, that wrap around the structure.
     Clinging vines, on the other hand, cannot attach themselves to netting or string. Their aerial roots or "holdfasts" adhere to almost any flat surface but they prefer slightly rough surfaces like unpolished stone or brick or rough bark. Examples are Boston and English ivy.
     It's important to know the eventual size or weight of the vine. The trunks of some clinging vines, climbing hydrangea for example, are woody and can require strong support in just a few growing seasons. Some nonwoody and even annual vines can grow so rapidly that they, too, require considerable support.
     Since some of the perennial vines are fairly slow-growing, I've included suggestions for a few annual vines within each section that might be helpful if you're starting an arbor and want quick growth and coverage while perennial vines are getting established.

Twining Vines
     American bittersweet, Celastrus scandens, is a woody vine native to Nebraska. Its strongest ornamental feature is its colorful autumn fruit, an orange capsule opening to reveal red seeds underneath. It bears best in full sun and foliage turns bright yellow in the fall. The fruits are favored by "turkey, grouse, quail, pheasants, mockingbirds, catbirds, bluebirds, cedar waxwings and cardinals" according to a newsletter of the UNLBGA Maxwell Arboretum.
     The fragrant flowers of goldflame (Lonicera x heckrottii) and trumpet honeysuckle (Lonicera sempervirens) have a long period of bloom, opening intermittently until frost and giving way to bright red berries. They are favored by birds, particularly hummingbirds. The plants grow to about 15' and like well-drained soil; they may be susceptible to mildew if grown in shade.
     Dutchman's pipe, Aristolochia macrophylla, is a fast grower, extending to 30' in one year. Its heart-shaped leaves can grow to 1' in diameter, making it ideal for screening and fast shade. Early summer flowers are followed by capsule-like fruits. Some sources recommend planting it away from the house since its fly-pollinated flowers are somewhat smelly.
     Chocolate vine, Akebia quinata, is known both for its semi-evergreen foliage and vanilla-scented dark maroon flowers in early spring. Small, fleshy purple fruits follow. It can grow to 30' and prefers moist but well-drained soil.
     The sight or smell of a wisteria in full bloom is not easily forgotten. Drooping clusters of lilac-colored flowers can be 18" in length. Bean-like velvety green seed pods follow. For Japanese wisteria, Wisteria floribunda, flowers occur in April or May. The blossoms of American wisteria, Wisteria frutescens, are somewhat less showy and occur June to August. American wisteria blooms on new wood and should be pruned annually. Japanese wisteria need only be pruned as needed to keep it in bounds. It requires strong support since a mature one can grow to 20-30'.
     Jan Riggenbach, gardening columnist for the Omaha World-Herald, recommends starting with a grafted plant since "seedlings may take ten years or more to flower." In her Midwest Gardener's Handbook, she writes "If you've done everything right and waited patiently, and yet your wisteria still won't bloom, try root pruning: slice down through the soil with a sharp spade, as if you were beginning to dig up the plant."
     Silver lace vine, Polygonum aubertii, has showy small, white flowers in late summer followed by translucent fruit. A fast grower, it can grow to 25' in one season.
     There are a number of annual twining vines that might be helpful if you're wanting quick cover while waiting for some of the slower-growing perennials to get established.
     The fruits of hardy kiwi, Actinidia arguta, are edible, ripening in autumn. Harlan Hamernik, owner of Bluebird Nursery, Inc. in Clarkson, particularly likes the variegated forms, Actinidia kolomikta 'Arctic Beauty' which has white flowers and variegated purplish leaves with splashes of white and pink on 3-5 year old plants, and Actinidia polygama with splashes of silver-white on the foliage.
     Another favorite of Harlan's is hops vine, Humulus lupulus 'Aureus', which has pale green foliage and cone-like fruits and also comes in variegated forms.
Scarlet runner bean (Kennedia prostrata) grows to only about 5'. Scarlet pea-like flowers bloom throughout the summer and into autumn.
     Morning glory and another member of the morning glory family, cardinal climber (Ipomoea spp. and Ipomoea x multifida), prefer full sun and well-drained soil and grow from 6-20'. The flowers of cardinal climber are a deep crimson with white throats, while morning glories bloom in a variety of colors throughout the summer.
     Black-eyed Susan vine, Thunbergia alata, is another possibility for a quick-growing annual vine. Flowers are white, bright orange or yellow, usually with deep, chocolate-purple centers and they bloom all summer.

Clasping Vines
     Clematis may be the most loved and best-known of all vines. The varieties hardy to Nebraska offer a wide variety of bloom color, bloom time (from spring through autumn), fragrance and even shape of the flower. Clematis grows best "with its feet in the shade and its head in the sun." If it is in full sun, plant it on the north side of a fence, shrub or perennial and cover it with mulch to keep the soil at its base moist and shaded. Good supports for clematis include wire screen, netting or narrow wooden lath. Clematis may take several seasons to flower.
Clematis montana is one of the early bloomers, offering white or pink vanilla-scented blossoms in May.
     Downy clematis blooms in May and June. Clematis macropetala 'Markham's Pink' has semi-double flowers of mauve and purple, and 'White Swan' has 2-2 ½" white flowers.
     Jackman clematis, Clematis x jackmanii, is a reliable, well-known favorite that does well in full sun or deep shade. Velvety violet-purple blossoms are 3-4" across in mid and late summer and vines grow to about 12'.
The abundant, bell-shaped yellow flowers of golden clematis, Clematis tangutica, that occur midsummer to late autumn give way to beautiful silken seed heads.
     The flowers of sweet autumn clematis, Clematis terniflora (previously C. paniculata or C. maximowicziana), are larger-4-5" in diameter, vary in color from white to purple to deep red depending on the variety, are almond-scented and bloom in early fall.
     The common name of porcelain berry reveals its most showy ornamental quality. The fruits of Ampelopsis brevipedunculata progress from green to light and then darker blue and then into deepening shades of purple. Since these colors often occur at the same time, the result is quite showy. Fruiting will be heaviest if the vine is grown in full sun and root growth is restricted. The vine grows to 15' and can become invasive, so a confined site is recommended.
     The fall foliage of some grapevines, particularly Vitis amurensis and V. coignetiae, can be stunning… flaming red, crimson or purple. The leaves of 'Variegata' are splashed with white. Vitis riparia offers excellent fruit for jelly or wine. All grapes are vigorous climbers and the shredding, woody bark is appealing throughout the year.
     For annual clasping vines, there is passion vine and sweet pea.
Sweet pea is a clasping vine that occurs both as an annual, Lathyrus odoratus, and a perennial, Lathyrus latifolius. The flowers of both are intensely colored and the vines grow 6-8'; flowers of Lathyrus odoratus are fragrant. Sweet peas can tolerate shade, but they do best in sun and bloom better in the heat than most vines.
     Few vines have flowers as exotic or intricate as the passionflower. The blossoms are fragrant and attractive to butterflies and hummingbirds. Blossoms of Passiflora caerulea are sky-blue and white; a dramatic red for Passiflora coccinea. The vines can grow to 30'.

Clinging Vines
     Any flat surface is suitable for the growth of clinging vines. The slightly rough surface of unpolished stone or brick works well. Though the aerial roots or "holdfasts" will attach themselves to wood surfaces, clinging vines are not recommended for wood because the dense growth of these vines allows no air circulation, providing an ideal environment for fungus. Also, if the wood surface will require painting, removal of the aerial roots of clinging vines is a painstaking and time-consuming process.
     Climbing hydrangea, Hydrangea anomala petiolaris, bears clusters of fragrant white flowers in early summer. The foliage is lush and dark green and the bark of older plants is peeling and cinnamon-colored. Though slow to establish, this vigorous, woody vine can grow to 50' so it should be grown on a structure that can bear the weight of the mature plant.
     The large palmate leaves of Virginia creeper, Parthenocissus quinquefolia, are bright red in autumn. A woody that can grow to 50', the berries and the cover it provides make it attractive to a variety of wildlife.
     Another plant in this genus is Boston ivy, Parthenocissus tricuspidata. It can grow 50' or more and the large, three-lobed leaves also have beautiful fall color. It can take sun or shade and almost any soil conditions.

Evergreen
     If you're looking for evergreen climbers, two possibilities are English ivy, Hedera helix, and wintercreeper, Euonymus fortunei. Both are clasping vines that require a solid surface for support.
     English ivy has glossy, dark green foliage that can become red or purple in cold weather. It grows best in fertile, well-drained soil. Cultivars of Hedera helix can be chartreuse, variegated, white-veined or purple and can range from very narrow foliage to almost circular, ruffled leaves.
     Wintercreeper also has many cultivars. Some varieties can climb to 15' if supported, though most stay under 5'. Variegated ones require full sun to achieve best coloring. It is susceptible to scale and can suffer winter burn so is best grown in areas sheltered from drying winds.

Overall
     Most vines require pruning only to keep them within bounds. With just a few exceptions, the vines listed in this issue can be pruned as needed at any time. Since the clematis that bloom in early summer (Clematis montana and C. macropetala) flower on the previous year's shoots, they should only be pruned after flowering. It's possible to get two periods of bloom from later blooming clematis like Clematis x jackmanii by pruning one side of the plant in January or February and the other side two months later. Since the vines intertwine, flowers will be distributed throughout the vine.
     Non-blooming wisteria should be pruned only as desired. The side shoots of flowering wisteria should be pinched back after the blooms fade.
     Other suggestions:
♦Though any of the twining or clasping vines will work, wisteria and porcelain berry vine are particularly good vines for chain link fences.
♦Most vines do well in sun or part shade. For full shade, possibilities are Dutchman's pipe and ivy.
♦Hummingbirds favor honeysuckle, cardinal climber and passion vine.
♦Fragrant vines include honeysuckle, hydrangea, silver lace vine and sweet pea.
♦Perennial pea, Virginia creeper, wisteria, honeysuckle and silver lace vine are drought-tolerant once established.
♦For quick growth, plant annuals or perennials like sweet autumn clematis, Virginia creeper, grape, silver lace vine or Dutchman's pipe.
♦Grape vines and hardy kiwi produce edible fruits.