As a long time follower let me start by thanking you all for the service you provide! During an expedition into our backyard we slowly came to the realization we were being taken over by this unidentified plant (or is it a weed?) We have managed to rule out Strawberry plant. We are beginner gardeners looking for some help before it’s too late! So plant or weed, keep or kill? Thanks
Thank you for your kind words on the service we provide.
I believe the plant in your photo is garlic mustard (Alliaria petiolata) which is an invasive weed native to Europe and now established in Ontario. I’ve been pulling a lot of my out of my own garden in recent weeks.
It is characterized by an elongated heart shaped leaf with a saw toothed edge. In it’s second year, garlic mustard produces a cluster of small flowers with four petals. Hundreds of seeds are produced by these tiny flowers and easily spread by people and animals. The seeds remain viable in the soil for many years and will grow in a wide range of sunny and shaded locations.
Garlic mustard is highly invasive and once established in the wild it readily displaces our native wildflowers. You will certainly want to get it out of your garden and fortunately it is relatively easy to root out. Be sure to dispose of it in the garbage and not in your compost or through any municipal garden waste disposal program.
Garlic mustard is similar in appearance to a number of other weeds. The garlic smell released by crushing one of the leaves will confirm its identity.
The Ontario’s Invading Species Awareness Program web site has some excellent information on garlic mustard and other invasive species. http://www.invadingspecies.com/invaders/plants-terrestrial/garlic-mustard/