During the winter we normally have henbit grow prolifically between the raised beds and takes over part of the chicken pasture (when there are no birds in there).... I went out to turn one of the raised beds yesterday. Got it cleared, not turned and then all the green, whatever it is growing around it. That stuff is all over my backyard. It's taken me over 2 years to turn all but a 20x20 spot to finally landscape and not I have this junk. Really makes me wish I still have Guineas. Pretty sure this stuff is burdock. Man I hate that stuf.
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This year it has been non-existent. I guess it can't handle sub zero.
http://en.wikipedia.org/wiki/Lamium_amplexicaule