UNITED STATES—Nature is competitive. Competition is natural. In the wild, vegetation competes for limited resources. Where sunlight is a limited resource within forest ecosystems, competition for it is fierce. Understory vegetation does what it can in the shade of taller trees. Taller trees strive to be the tallest for more sunlight. Vines are the most aggressive competitors of all.
Vines are blatantly exploitative. They rely on trees to do the work of growing to the top of the forest canopy. Then, they climb into and over such trees to grow even higher than the trees do. Some can overwhelm and even shade out and kill the trees that they rely on for support. Strangler fig literally strangles its hosts as it develops its own supportive trunks.
Vines climb with clinging roots, twining stems, tendrils, twining leaves or hooked thorns. Some are perennials or even annuals. Some sprawl over the ground while juvenile, and then climb as they encounter support. As they reach the top of their supports, such vines generate shrubbier adult growth. Then, such adult growth can bloom and generate seed.
Vines must know their place.
English ivy, for example, is a practical groundcover plant in its juvenile form. However, it becomes a clinging vine when it finds support. It quite often climbs shrubbery, trees and buildings. If left unattended, it develops into shrubbier growth that blooms and produces seed. Such shrubby growth shades desirable vegetation, and on buildings, promotes rot.
Carolina jessamine, lilac vine, mandevilla and wisteria climb by twining stems. They are generally not as potentially destructive as clinging vines. However, they can crush lattice or small trellises. Wisteria can crush substantial trellises. Like English ivy, star jasmine is likely more popular as a ground cover. It performs double duty, though, as a twining vine.
Bougainvillea neither clings nor twines. It merely produces vigorously tall canes that flop over on top of their support. Long thorns help to anchor them into place. Therefore, such canes need a bit of help to climb trellises or other support. They must be tied in place or woven into their trellises. Various other vines exhibit various and distinct characteristics.
Highlight: English Ivy
With containment, English ivy, Hedera helix, is a dense and evergreen groundcover. As it matures, it eventually excludes weeds. Containment is very important, though. It grows fast into trees and shrubbery, and clings to buildings. On buildings, it promotes decay of wood siding and ruins paint. As a vine, it is safe only on concrete and cinder block walls.
Juvenile growth of English ivy is mostly rather compact. Ideally, it is less than six inches deep. It gets a bit deeper where shaded. Leaves are as wide as three and a half inches. Stems develop roots where they touch the soil. Adult growth is shrubby, though, and can protrude several feet higher than its support. It blooms and produces small black berries.
‘Hahn’s’ is probably the most popular cultivar of English ivy because it branches so well. ‘Needlepoint’ has elegantly narrow foliar lobes. Cultivars with yellow or white variegation grow notably slower. They are popular as foliar components in big pots of mixed annuals and perennials. Some of the hundreds of cultivars are more popular as houseplants than outside.
Tony Tomeo can be contacted at tonytomeo.com.
