Outdoors_lol_08-03

Jeff Green | Jan 24, 2008

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Dog Strangling Vine? It may seem strange to be writing about a vine in the middle of winter; however, it is a good time to spot this strangling vine in its woody state while the forest is bare of foliage.

My husband and I, for the past few years, have observed a woody vine that appears to strangle young trees. It winds itself so tightly around the trunk of a tree that it appears to choke the life out of its victim. It doesn’t have a preference for any one type of tree but, from my observations, climbs cedars, maples, birches, or whatever is in its way and can grow to several meters in length.

We are not sure if this vine is the Dog Strangling vine but, after much research, there doesn’t appear to be anything similar. If there is a person who is knowledgeable on this subject, I would really appreciate hearing from you.

As a means of trying to save some of the trees, we cut the vine at some point, to kill it and then try to loosen its grip and pull it off the tree. Even if this is only a stop gap measure, it does give a certain sense of satisfaction and may help to save trees in our immediate area. When you walk along a wooded trail, look closely at the smaller trees and you may see some of these vines. It seems to be especially prevalent in eastern Ontario, from Toronto through to Ottawa.

In trying to research this vine, I notice there have been a number of newspaper articles on the subject. According to the information given, the Dog Strangling vine (Pale or Black Swallow Wort) is highly invasive and will thrive in shade, sun and all soil conditions. It will spread rapidly, reduce or eliminate other plants and is extremely difficult to control. Rather than cutting the vine, as I do, it is better to dig the root up but this, I am sure, is easier said than done as the roots are usually entangled in an underground root system.

Because the plant is alien to Canada, it does not have any natural enemies. It appears that attempts to control it, have, at most, only slowed it down.

The Dog Strangling vine is a member of the Milkweed family. It is interesting to note that Monarch butterflies may lay eggs on the leaves of this vine but the larvae are killed by poison in the plant.

If you check on the internet, there are a number of sites, including the Ministry of Agriculture, that provide pictures and information on this vine, particularly in its early stages of growth when it is green and leafy.

Observations: Mike Brown has reported seeing very large birds during the Christmas season. He observed the birds along Bedford Road in the vicinity of North Otter Lake and also at Little Bass Lake. The birds were dark brown in colour with wingspans of six or seven feet. He was close enough to see the claws and beaks of the birds and to be able to tell they were not Ospreys. After consulting his bird books, Mike has concluded the birds could have been juvenile Bald Eagles. With ever increasing sightings, it certainly appears the population of this magnificent bird is on the upswing.

Please contact me if you have any unusual sightings of wildlife so that I can share with our readers. My email address is This email address is being protected from spambots. You need JavaScript enabled to view it.