English Ivy

February 21, 2021March 3, 2021
Flora and Fauna, Invasive Species
by dhir

All photos taken by the author. Last updated March 3, 2021.

A carpet of invasive English ivy near a small stream. This invasive species is easy to find in yards, urban forests, and, sadly, almost anywhere plants are sold. This area in an urban forest should be filled with native ferns, shrubs, smaller plants like mosses and saplings.

If you search “English ivy” in your browser, you will likely find sites explaining how to care for it and where to buy it. It is popular because of its ability to quickly fill in an area with lush year-round leafy green. Buyer beware! In British Columbia, the top hit should be how to get rid of it. The Invasive Species Council of BC’s factsheet on English Ivy says:

English ivy is a widely planted ornamental that arrived in North America during colonial times. It is indisputable that English ivy inhibits the growth and regeneration of native wildflowers, shrubs and trees through shading smothering and associated harmful pathogens.

You are likely within a block of English ivy once you step outside of your dwelling, just look in each yard as you pass. If you are driving, and it is safe to do so, look at the roadside deciduous trees and see if you can tell which leaves do not belong. If you are in a forested area, you may see it climbing trees like in these next four photos:

English ivy climbing a large, mossy tree. There are many varieties of leaf shape and colour.

These deciduous roadside trees may look green all winter, but the leaves are not their own. The extra weight of ivy vines and leaves may make it easier for a strong storm to blow down a tree.

An ivy-covered deciduous tree in early March.

A western redcedar tree with the leaf-less remains of ivy vines on the trunk.

Ivy leaves on the ground. I’m not sure if the reddish leaves are a red variety or diseased.

The leaves curve where they attach to the stem at the base of this variety creating a kind of cup-shape.

The lower (left) and upper surface (right) of one variety of English ivy.

The leaves rise perpendicularly from fast-growing runners. The runners easily travel horizontally across bare ground and low plants or vertically up fences, buildings, and trees.

Ivy leaves typically have 5 points or lobes. There are countless cultivars (cultivated varieties) of English ivy so you may come across leaves that are more or less lobed, of different sizes, and of different shades of green and white. Just scroll through a Google images search for English ivy if you want to see other varieties.

English ivy on a forest floor. You can see from this angle how it will shade out shorter plant species, preventing them from getting the sunlight they need to thrive.

English ivy (Hedera helix) is also known as common ivy. It grows horizontally on the ground producing many juvenile leaves with 3-5 lobes. When it climbs, it will grow adult leaves (ovals with pointed tips) and flowers (I don’t have a close-up photo of the adult leaves yet). If pollinated by insects, the flowers produce seed-containing berries in fall which are eaten by birds.

There are three other species of ivy in the same genus (H. caucasigena, H. colchica, H. hibernica) and many other plants that have “ivy” in their common name but belong to different genuses and families, such as poison ivy, American ivy, and redwood-ivy. H. hibernica (Irish ivy) is similar to English ivy in appearance. It is also used as ground cover and is invasive in our area.

So head outside this week, or maybe just look around inside your home, and identify the first invasive species in my blog, English ivy. Then cut it down and dispose of it carefully as it can easily grow from cuttings.

Book:

“Hedera.” Flora: over 20,000 Plants and Their Cultivation Requirements, Firefly Books, 2003, pp. 678–680.