Coastal Invasive Species Committee

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Ivy (Salt Spring Island Concervancy)

ALIEN PLANT INVADERS: IVY

By Jean Wilkinson, Stewardship Committee, Salt Spring Island Conservancy

By learning about and dealing with invasive plant invaders, we can help protect the natural balance and diversity of life on our properties and this beautiful island. Our mild climate provides perfect growing conditions for a wide variety of plants, but some that have been brought here are taking over!

One of the most aggressive and problematic of these is English Ivy, which carpets large areas of the ground, clambers up trees, and smothers the native vegetation. Having been introduced to the region, it has few natural enemies or diseases, so easily out-competes other, more beneficial plants. It invades wooded areas and creates a monoculture, upsetting the balance of nature and reducing local biodiversity.

However, we can all play a part in tackling this problem, since it's fairly easy to find and remove ivy vines. As a first priority, cut those which are growing upwards. This will prevent them from debilitating trees and bushes or damaging structures. It will also help stop the spread of this pesky plant, as ivy usually develops flowers and seeds when it grows upwards. After the climbing vines are dealt with, start clearing away those on the ground, freeing up space for a variety of other species to re-establish and grow.

When landscaping, there are a number of alternatives to ivy that don't threaten local ecosystems and are recommended by the Invasive Plant Councils of BC, Washington and Oregon. Many of these species also have flowers and/or provide food or shelter for local birds, mammals and insects. Now is the perfect time to start removing the Ivy and plan for a more wildlife-friendly, bio-diverse replacement!

ENGLISH IVY and IRISH IVY – QUICK FACTS ABOUT THESE HORTICULTURAL BULLIES:

Identification – Hedera helix and Hedera hibernica– vigorous woody evergreen perennials. Juvenile form is a creeping ground-cover vine with leaves usually 3-lobed. Adult reproductive form has erect, shrubby stems with diamond-shaped leaves and tight clusters of small white flowers developing into purple or black berries.

Impacts – grows densely, overwhelming native plants on the forest floor by depriving them of sunlight, nutrients and water. Climbs and smothers trees and bushes, leads to root-rot, and can topple them over with its weight. Can increase fire hazard, damage buildings and harbour pests such as rats.

Found –in moist coniferous, mixed and deciduous forests, especially near urban and residential areas

Spreads – via seeds in the berries (distributed by birds), by underground rhizomes and by above-ground runners

Control – Prevent seed production and protect trees and shrubs by cutting vines from a 1 metre wide band all the way around trunk and one metre out from base of each tree. This band must be kept clear, but upper vines may be left to die, especially on trees that are dead and at risk of falling. Pull or roll up vines on the ground. Use hand trowels to remove as much of the root system as possible, while minimizing soil disturbance and damage to other species. Wear gloves, as ivy sap may cause dermatitis.

Disposal – Dry vines and pile them up to rot on a tarp or pavement so roots won't resprout. If seeds are present, avoid spreading them. Stem and root fragments can regenerate in soil, so monitor the area for re-growth.

Alternatives - (+ will grow in shade and # full shade, M prefers Moist conditions, D prefers Dry, DT is Drought Tolerant)

Native ground-covers: Kinnikinnick + D, DT; Bunchberry + M; Evergreen Violet # M,DT; Wood Sorrel # M; Wild Lily of the Valley # M; Wood Strawberry # D, DT; Beach Strawberry D,DT;

Taller native plants: Salal # M to D, DT; Oregon Grape + M to D, DT; Sword Fern # DT and Deer Fern # M. Non-natives: Prostrate Ceanothus D,DT; Allegheny Spurge # M; Creeping Juniper D,DT; Star Jasmine +M; Barren Strawberry # M,DT; Creeping Raspberry # M,DT; Barrenwort + M to D; Crinkle Leaf Creeper + DT; Bearberry D; Wintercreeper + M; Boxleaf Honeysuckle # M; Sweetbox # M; Climbing Hydrangea + M

More Info: Salt Spring Island Conservancy Stewardship Committee 250-537-4877, Coastal Invasive Plant Committee www.coastalinvasiveplants.com , Invasive Plant Council of B.C. www.invasiveplantcouncilbc.ca