This plant may seem like a great seasonal gift or decoration, but beware!
I’m an evergreen shrub that can grow really tall,
K. Newell
And my leaves stay on through winter and fall,
I’m used for sharing holiday cheer,
While sneakily spreading all over the sphere!
English Holly (Ilex aquifolium) is an evergreen shrub or tree that was brought over from the British Isles and Southern and Central Europe and grown for its bright red berries and spiny, dark green evergreen foliage.
So, what makes this plant the grinch that stole habitat? Well, English Holly has become seriously invasive because of its adaptability to grow in shade or sun, and the ease with which its seeds are spread by birds. Seedlings are now commonly found in mixed deciduous and coniferous forests, along the edges of wetlands, and especially near residential areas.
As the riddle hinted, English Holly can grow quite tall – between 5 and 15 m, to be precise. As a result, it casts deep shade that deprives native plants of light. In addition, its roots effectively out-compete many native species for nutrients and water; it is a notorious water hog, thus preventing native plants from obtaining sufficient water.
English Holly leaves are thick, glossy, dark green and wavy, and 2 – 7 cm long, appearing in an alternate (zig-zag) pattern along the stem. The leaves have sharp, stout spines along the edges, although leaves may be smooth on mature branches. Flowers are whitish, sweetly scented and inconspicuous. Female trees produce bunches of red, yellow or orange berries in winter that are poisonous to humans and pets. English Holly can grow from seed (in berries) and vegetatively.
Unfortunately, English Holly is still grown commercially and commonly used in decorations, floral arrangements, and landscapes. However, this jolly invasive has a native look-alike you can plant instead! Oregon Grape (Mahonia aquifolium) is another evergreen shrub with sharp spines along the leaf margins. You can distinguish Oregan Grape from English Holly by its bright yellow flowers, purplish-blue berries, and opposite leaves. It is also much smaller, reaching 2.5 m tall at maturity. You can read more about native alternatives in the Grow Me Instead booklet for BC.
As SSISC’s Plant List shows, our objective is to contain English Holly infestations in Squamish, while preventing the plant’s spread to Whistler and Pemberton. So, next time you stumble upon some English Holly, don’t forget to report it!
Add Comment