Not Wanted - A photo gallery of invasive species

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Not wanted - a photo gallery of invasive species

A brief and pictorial introduction to some invasive alien species

 

Trees

Norway Maple (Acer platanoides)
Norway Maple leaves

Photo: John Oyston - Toronto ravine

Norway maples are easily identified by the milky sap when the leaf stalk (petiole) is cut:

:Sap of Norway Maple

Photo: John Oyston - Toronto ravine

Norway maple seedling in fall

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:

Buckthorn berries

Photo: John Oyston - Oak Hills Farm

There are sharp spikes on the end of the branches

Spikes on Buckthorn

Photo: John Oyston - Toronto ravine

It has very untidy ragged bark:

Buckthorn 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:

Buckthorn Stumps

Photo: John Oyston - Oak Hills Farm

Brush pile of felled Buckthorn:

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.

Autumn Olive shrub

Photo: John Oyston - Oak Hills Farm

They have trumpet shaped flowers...

Autumn Olive Flowers

Photo: John Oyston - Oak Hills Farm

... and spotted red fruits which can be used to make jam:

Autumn Olive berries

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.

Mass of Dog Strangling Vine

Photo: John Oyston - Toronto Ravine

Clump of DSV

Photo: John Oyston - Toronto Ravine

Dog Strangling Vine flower

Photo: Deborah Dale

DSV in winter

Photo: John Oyston - Toronto Ravine

DSV vines in winter, spreading its seed from opened seed pods

Garlic Mustard

Clump of Garlic Mustard in flower

Photo: John Oyston - Toronto Ravine

Garlic mustard in winter

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.

English Ivy leaves

Photo: John Oyston - Toronto

Periwinkle (Vinca minor)

Pretty pale blue flowers and glossy evergreen leaves, but can take over natural areas.

Periwinkle leaves

Photo: John Oyston - Toronto

Vinca minor blooming in a Toronto garden:

Mass of Vinca in bloom

Photo: John Oyston - Toronto

Vinca minor flower

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. .