Pretty, but Invasive: Purple Loosestrife

On a recent trip up north, I again noticed the plant above in wetland areas, especially in the NJ wetlands. Very pretty, this plant is the highly invasive purple loosestrife,  Lythrum salicaria.  The sale of this plant is banned in many states, but I have seen it for sale at flea markets, yard sales and small-scale, charity plant sales or swaps.  AVOID IT AT ALL COSTS!  Loosestrife infestations are costly to manage, hard to eradicate and actually decrease the sites available for nesting water fowl.  (If you see this plant, differentiate it from the native Winged Loosestrife, Lythrum alatum, before you eradicate it. "As compared to the native plant, purple loosestrife has wingless stems, a larger size, and slender willow-like leaves that often have hairs" from:  http://davesgarden.com/guides/pf/go/31778/#ixzz36FN21Y7O )
 For additional information, go to: http://www.ecy.wa.gov/programs/wq/plants/weeds/aqua009.html