I don't remember planting this... could it be somekind of Allium? A. ursinum? I am not sure, will post a photo when it blooms.. it has been 'up' pretty long time already, waiting for the bud to open..
Best way to tell if it is an Allium is to nip the tip of the leaf off and smell it. A ursinum - Ramsons has a very strong oniony smell. I have it in my garden but until it flowers I wouldn't even hazard a guess at species, there are several with broad leaves.