Vine

A vine is a plant that grows by trailing or climbing, using stems, lianas, or runners. The word can also describe those stems or runners themselves, such as when they are woven into wickerwork. In some regions, like the British Isles, "vine" typically means only grapevines, while "climber" covers all other climbing plants.

Some plants are always vines, while others only become vines when support is available. For example, poison ivy and bittersweet grow as low shrubs without support but turn into vines when they find something to climb. The long stems of a vine serve two main purposes. First, a vine can use rocks, other plants, or structures for support instead of building thick, sturdy tissue, saving energy to reach sunlight. This strategy has been very successful for plants like kudzu and Japanese honeysuckle, which are invasive exotics in parts of North America. Certain tropical vines even display skototropism, growing away from light (a form of negative phototropism) to find a tree trunk, which they then climb toward brighter areas. Second, the vine growth form allows plants to spread quickly across large areas without climbing high, as seen with periwinkle and ground ivy. It also helps plants thrive where small patches of fertile soil sit next to sunnier, exposed areas with little soil—the vine roots in the soil while its leaves reach the light.

The climbing habit has evolved independently in many plant families, using different methods. These include twining the stem around a support (morning glories), using adventitious clinging roots (ivy), twining petioles (Clematis), tendrils from shoots (Vitaceae), leaves (Bignoniaceae), or even inflorescences (Passiflora), tendrils with adhesive pads (Parthenocissus), and thorns or hooked structures (climbing rose, Artabotrys hexapetalus). The climbing fetterbush (Pieris phillyreifolia) is a woody shrub-vine that climbs without roots, tendrils, or thorns—it pushes its stem into bark crevices of fibrous-barked trees like bald cypress, where the stem flattens and grows upward under the host's outer bark, then sends out branches near the top.

Most vines are flowering plants, divided into woody vines (lianas) like akebia, wisteria, kiwifruit, and common ivy, and herbaceous (nonwoody) vines like morning glory. An unusual group is the fern genus Lygodium, or climbing ferns, where the fronds (leaves) do the climbing, not the stem. These fronds unroll from the tip and theoretically never stop growing, forming thickets over other plants, rockfaces, and fences.

A twining vine, or bine, climbs by growing its shoots in a helix, unlike vines that use tendrils or suckers. Many bines have rough stems or downward-pointing bristles for grip. Hops, used in flavoring beer, are a commercially important bine. The term "woodbines" can refer to both bines like Lonicera periclymenum (a honeysuckle) and some Parthenocissus species with tendrils. The direction of a bine's twist is autonomous—it does not follow the sun, so it does not depend on the hemisphere. Some bines always twine clockwise, such as runner bean (Phaseolus coccineus) and bindweed (Convolvulus species), while others twine anticlockwise, including black bryony (Dioscorea communis) and climbing honeysuckles (Lonicera species). This contrast inspired the satirical song "Misalliance" by Michael Flanders and Donald Swann, though the lyrics mistakenly describe honeysuckle as right-handed and bindweed as left-handed.

In horticulture, "vine" also applies to Cucurbitaceae, like cucumbers, where botanists call them creeping vines. In commercial agriculture, trellis netting is used to guide their coiling tendrils. Gardeners often use climbing plants for quick displays, training them over walls, pergolas, fences, or other plants. Some climbers attach themselves; others need tying and training.

Vines vary widely in size, form, and evolutionary origin. Charles Darwin classified them into five groups based on climbing method: twining plants, leaf climbers, tendril bearers, root climbers, and hook climbers. Vines have multiple evolutionary origins, are mostly found in tropical locations, and can grow in both deep shade and full sun due to their broad range of light tolerance.