Around the Garden

Trouble in Paradise:

Perennial invasives are showing real vigor this year, what with the dense snow-pack and subsequent heavy rains. Vines may be the most obnoxious invasive, with truly insidious modes of survival.

Most people know (or think they do) poison ivy, but that doesn’t keep them from getting rashes. Poison ivy employs several defensive strategies, including secreting a highly irritating liquid in all its parts. Urushiol is an irritant whether you contact the plant’s roots, stem, leaves or berries. Eating this plant is almost as bad as inhaling smoke from burning poison ivy. Birds, on the other hand, can eat the berries with no problem (I’m told most birds have no taste buds.) Insects rarely eat the leaves, and I have never seen deer browse on poison ivy.

Bird dispersal is the number one way poison ivy spreads, but the plant also does a great job of burrowing under the soil and popping up anywhere and everywhere.

Of course, its ultimate goal is always to reach sunlight, so trees are a perfect vehicle toward that end. Get rid of poison ivy by pulling it out of the ground, roots and all. Plastic newspaper bags can be used, over a pair of sturdy gloves (plastic can always tear.) When you have yanked a length of poison ivy, simply turn the plastic bag inside out, and bundle the whole thing into the trash.

Be careful when poison ivy is firmly attached to a tree’s trunk – tiny root hairs embed themselves in the fissures of the tree’s bark, so do not rip the bark off the tree. A large poison ivy vine should be sliced through at intervals from the base of the tree upward. A small pruning saw works well – just be sure to wipe the blade with a paper towel before using it elsewhere.

Many people confuse Virginia creeper with poison ivy, but always count the leaves on the leaflet: Virginia creeper has five, poison ivy has three.

Virginia creeper is invasive and vigorous, but not nearly as obnoxious as poison ivy or Oriental bittersweet. Oriental bittersweet is not poisonous but that’s the only positive thing about it. It’s the worst pest in my garden, because it strangles trees and shrubs by twining tightly around their trunks, preventing the necessary expansion of the cambium. You’ve probably seen trees along highways, completely shrouded in lush green vines – that’s Oriental bittersweet. Unless you’re in Mississippi, in which case it’s kudzu.

That mass of foliage is another way Oriental bittersweet kills trees: the added weight of it makes trees top-heavy, so they are more prone to wind-throw or toppling when soil is too wet to hold onto the tree’s roots. Below is a rogue’s gallery of the plant, from its cute baby stage up to the killer vine stage.

Unlike poison ivy, bittersweet can be pulled safely with just gloved hands, and it comes out of the ground fairly easily. Take my advice: pull it whenever you see it, before it sets seed and propagates all over the place.