Alerts & Links

From Hayley Anderson, Terrestrial Invasive Species Outreach Liaison, Ontario Federation of Anglers and Hunters, Phone: (705) 748-6324 ext 243 If anyone wishes to report sightings of the following or any other invasive species, they can contact the invading species hotline at 1-800-563-7711 or report them online at

Dog-Strangling Vine – Native to Europe (Ukraine) – Introduced into the N.E. US in the 1880’s and possibly introduced to Canada from the Experimental Farms in Ottawa where it was being tested for uses as lifejacket filler and possible rubber substitute during WWII – Herbacious perennial – vines die every winter and will stay twined around trees etc – Flowering begins late June and flowers are dark purple – Seed pods produce fluffy white seeds similar to native milkweed, which are carried by wind – Prefers open sunny areas but will grow just about anywhere – especially in filtered shade (pine plantations) – Forms dense colonies and outcompetes/outshades native species – Spread is expected to increase across North America & expand rapidly into new areas – Prevention is the best control – always remove seeds, mud and plant parts from yourself, your equipment and pets before moving to a new area & try to limit your travels in DSV infested areas after seeds have been released (late August) – Seeds can remain viable in the soil for up to 5 years – so control must continue for several years to be effective

Garlic Mustard – Native to Europe – Introduced by in late 1800’s by early settlers as food source/potherb green – Biennial plant (first year as basal rosettes which survive over winter, second year as flowering stalk which produces seed) – Grows up to 1m in height with white flowers produced in May – Seed pods can produce thousands of seeds per plant, and this is how it is spread – Thrives in shade but can grow in a multitude of habitats & wide variety of soils – Can enter and establish itself within a stable, healthy forest site – so prevention measures (same as DSV) should be taken to ensure it is not spread to new areas – Roots contain Sinigrin, which interferes with the mychorrizal (beneficial) fungi in the soil that aides tree growth – Also allelopathic, emits chemicals which alter the soil chemistry and prevents native plants from growing – Promising research shows GM may be out-competed by pulling then planting native species (Bloodroot and Mayapple) at 5-9 plants/sq m

European Buckthorn – Native to Europe – Introduced in 1700’s (for use as hedgerow/fencing) – Grow in large shrub growth form with few to several stems – Drought and Shade tolerant and can grow in a wide variety of sites (I’ve seen it growing under complete shade in Cedar plantation) – Female trees produce berries by late summer, which persist on the tree throughout winter – berries have a laxative effect on the birds/animals that eat them and this is how the plant is spread – Leaves are egg-shaped, with veins that curve towards the centre, and there will often be a small thorn between branches – May also be allelopathic – Seedlings (when quite small) can be pulled by hand or by using weed wrench – Control may be best started by identifying prolific seed producing female trees first and removing them

Japanese Knotweed – Native to Asia – Escaped ornamental, planted in gardens and still available at some nurseries – Semi-woody perennial, thick layers of stems and leaves produced will mulch out any competitors – Looks similar to bamboo (but not related) – hollow stems with swollen nodes – Leaves have a pointed tip and flat base – Flowers are white and produced along the stems – Requires sun & can often be found growing along riverbanks and rail-beds – Shoots and roots can grow through concrete and asphalt

Norway Maple – Native to Europe, first introduced in the 1700’s as an ornamental – Widely planted as a street tree after Dutch Elm disease wiped out Elm trees in the 1930’s and 40’s because it is tolerant of compacted soils and pollution – Still used quite widely as a street tree, Crimson king is one of the cultivars – Able to grow in deep shade – has infested ravines in Toronto – seedlings form a thick mat and can choke out natural regeneration of native tree species – Best control is to phase out its use as a street tree and substitute native maples instead

Giant Hogweed РNative to Asia РEscaped ornamental, becoming more common in southern Ontario РVery LARGE member of the parsley family Рgrows up to 5 m (16ft) in height РStem is bristly, hollow, and green with purple splotches РFlower umbels and leaves can be up to 1 m across Рwhite flowers similar to our native species Cow Parsnip or Angelica but much, much larger РHEALTH HAZARD Рthe clear, watery sap of giant hogweed contains toxins that cause photodermatitis (increase our skins sensitivity to sunlight) skin contact with the sap followed by exposure to sunlight can result in painful burns and blisters