Wondering about persicaria (Virginia knotweed). It is native however growing vigorously in the ravine right behind my property . Is it currently on any aggressive/vigorous “watch lists?” I had originally planted as a shade plant but the ravine has become sunnier and ther persicaria is doing well. Maybe too well!
Thank you for contacting Toronto Master Gardeners.
Persicaria virginiana, commonly called Virginia Knotweed, Virginia Smartweed or Jumpseed is a vigorous native perennial plant that tolerates both sun and shade. It prefers to grow in average to moist conditions, is not fussy about soil type or pH and is very tolerant of urban pollution. As the Jumpseed name implies, the seeds disperse several feet when the mature seed pod opens.
While it is not on an invasive species, given the above characteristics, Virginia Knotweed spreads easily. To control its spread into your local ravine (presumably it was not growing there before you planted it in your garden), I suggest you deadhead the flower stalks in late summer before seeds are dispersed. I grow this plant in my garden, and this is what I do to keep it under control.
Alternately, you could replace this plant with a more benign native species. For ideas of plants you might grow, check out the Credit Valley Conservation publication Native Plants for Pollinators.