Not Wanted - A photo gallery of invasive species
Not wanted - a photo gallery of invasive species
A brief and pictorial introduction to some invasive alien species
Trees
Norway Maple (Acer platanoides)
Photo: John Oyston - Toronto ravine
Norway maples are easily identified by the milky sap when the leaf stalk (petiole) is cut:
:
Photo: John Oyston - Toronto ravine
Photo: John Oyston - Toronto garden
They produce thousands of small seedlings which choke out native plants.
Common Buckthorn (Rhamnus cathartica)
Most easily recognized by its very glossy berries in fall:
Photo: John Oyston - Oak Hills Farm
There are sharp spikes on the end of the branches
Photo: John Oyston - Toronto ravine
It has very untidy ragged bark:
Photo: John Oyston - Oak Hills Farm
Controlled by cutting down and spraying the multiple trunks with herbicide to prevent re-sprouting. Not the two tone appearance of the stumps:
Photo: John Oyston - Oak Hills Farm
Brush pile of felled Buckthorn:
Photo: John Oyston - Oak Hills Farm
Autumn Olive and Russian Olive (Elaeagnus umbellata and E. angustifolia)
These ornamental trees are planted for their attractive silver leaves, but an escape into the wild.
Photo: John Oyston - Oak Hills Farm
They have trumpet shaped flowers...
Photo: John Oyston - Oak Hills Farm
... and spotted red fruits which can be used to make jam:
Photo: John Oyston - Oak Hills Farm
Ground covers
Dog strangling vine: (Cynanchum rossicum)
Takes over the forest understory or exposed banks. Very common in Toronto ravines and along Don Valley Parkway.
Photo: John Oyston - Toronto Ravine
Photo: John Oyston - Toronto Ravine
Photo: Deborah Dale
Photo: John Oyston - Toronto Ravine
DSV vines in winter, spreading its seed from opened seed pods
Garlic Mustard
Photo: John Oyston - Toronto Ravine
Photo: John Oyston - Toronto Ravine- December 2010
Garlic mustard remains green into winter, giving it a competitive advantage over other plants.
English Ivy (Hedera helix)
Less invasive than the above, but should not be planted where it can spread into natural areas. It is a major problem in BC and the Pacific Northwest, where it has taken over hundreds of acres of parks and natural areas.
Photo: John Oyston - Toronto
Periwinkle (Vinca minor)
Pretty pale blue flowers and glossy evergreen leaves, but can take over natural areas.
Photo: John Oyston - Toronto
Vinca minor blooming in a Toronto garden:
Photo: John Oyston - Toronto
Photo: John Oyston - Toronto
Invasive species differ in different areas. For example, Kudzu vine grows rampantly in the southern United States but has not been a problem in Canada until recently, when it was noticed growing wild near Point Pelee in south-west Ontario.
Pictures of species which are invasive in your area would be appreciated and will be added, with credit, to this "Rogues Gallery". Please send good quality images, preferably in JPEG format, to This email address is being protected from spambots. You need JavaScript enabled to view it. .
