Scary 20-Foot Weed Invading Ontario Can Blind You 29.84K Max Read 07/12/10 01:04AM Filed to: botany botany Plants Giant hogweed Canada Ontario Poison burns Blindness Giant hogweed, an enormous plant whose sap can burn skin—not to mention cause blindness—has been found in Ontario. If you see it, contact the authorities, and maybe try shooting at it with a gun, or something. [CBC via]