With summer’s arrival, the garden bulks up. It may seem like new growth has surpassed the gardener’s ability to maintain. This is especially so with vines, some good, some bad, and some even ugly.
A particularly thuggish vine seems to be taking over, seizing garden space, tree lines, anything that sits long enough. The oriental bittersweet or Celastrus orbiculatus has become abundant in recent years, a weedy vine of enormous proportions. As seedlings I find them carpeting the ground, easy to pull and simple to identify with orange roots. If left another year, it’s an entirely different struggle, one met with resistance to tugging and a vigor that rivals most weeds you encounter. Spread by birds, as most vines are, the red berry clusters of fall and winter disappear quickly as the pulp is eaten and seed dispersed. In terms of damage to surrounding trees, oriental bittersweet rivals wisteria and kudzu, the ultimate bullies that steal sunlight and form a hulking framework of branches which weigh down all beneath. Their Achilles heel is the singular source of each vine, a woody stem that is best cut as close to the ground as possible, followed by frequent re-cuts. All of this before they fruit (of course), to prevent new arrivals.
There are native options, all three prior vines are not. Even so, vines climb and often need a heavy pruning hand to conform to limited spaces. The non-Japanese, native honeysuckle or Lonicera sempervirens will grow fifteen to twenty-five feet tall. Flowering on old or new growth, they are easily tamed to form a handsome trunk and frame with time. Flowers are orange, red, or yellow and non-fragrant. One of the first to leaf out in spring and last to lose their leaves in fall, well suited to screening or training up a wall.
Crossvine or Bignonia capreolata can reach fifty feet with orangish flowers in heavy clusters. In the same family as trumpet vine, the two are aggressive. I generally let trumpet vine or Campsis radicans flower (late June into July), and then cut the vine back severely. Best done every year and repeatedly to discourage size. Left to their own devices, the spread seems limitless. All three of these natives are favored by hummingbirds with brightly colored, tubular flowers, and high nectar.
A challenge is finding small vines, the ones used to cover adorable tuteurs or ornate trellis’s. There has been a lot of breeding in clematis to do just that. Two breeders, Raymond Evison and Poulsen Roser have been working to fill the void with compact hybrids which are tagged “Evipo”. My clematis ‘Diamantina’ is on a four foot support, which it fits perfectly; a double purple from the same breeding line.
Bottom line, when it comes to planting trailing plants, it’s best to do your homework. Far too many invasive vines are sold and the ensuing job of keeping them in check can rapidly disintegrate. In most cases, that cute trellis will not hold that monster up.