Saturday, June 9, 2012

It's a creeper! It's a crawler! It's English Ivy!

Species name: Hedera helix

Common name: Common ivy, English ivy

Location: Ontario

As you can probably guess from the common name of this plant, its origins are in Europe (and also Asia). It's a somewhat unusual plant in that it is an evergreen species, which contributes to its invasive properties in that it can photosynthesize in the winter. This plant produces structures called rootlets along the stem, which help anchor the vine to any surface that's suitable. When there isn't a suitable surface, they act as regular roots by anchoring the plant into the ground and absorbing water and some nutrients. If you're really observant, you'll notice in the top two pics that English ivy and Madagascar periwinkle (that you can read all about in a previous blog post HERE) seem to be able to live together quite nicely, completely covering the ground with their vines (and that's a relatively high traffic area, too). Both plants must be flooding-tolerant, since that location in the back yard can get incredibly soggy during the spring melt and during the summer's intense rains. The ability of this plant to out-compete other plants is so impressive that English ivy often creates "ivy deserts" where it has strangled out all other plants and is all that exists on a landscape. This can be contrasted with the plant kudzu, which is an invasive vine in the United States that has choked out ground cover, shrubs and trees in Florida and Georgia (and is moving its way north).

John Gerard plays an important role in the historical uses of this plant, like Solomon's seal. He once advocated that soaking leaves in warm water would create a tonic that could be used to help eye soreness and dryness. I would absolutely not recommend this as a modern treatment for dry eyes (aside from the fact that you should never, EVER mess with "home treatments" when it comes to your sight) since English ivy can produce an intense allergic reaction upon contact with a chemical contained in the leaves called falcarinol. On the skin it produces contact dermatitis (a rash-like reaction), but in contact with the eyes it can induce blindness if you're sensitive to the chemical. Interestingly enough, most people with this sensitivity usually greatly dislike carrots since they also contain the same chemical and can produce an "itchy mouth" (I'm sure there's got to be a technical term for that...). Historically, the berries of this plant have also been used to treat bronchitis.