Definition of purple loosestrife in English English dictionary
a semi-aquatic herbaceous plant, Lythrum salicaria, having long spikes of purple flowers
An Old World marsh plant (Lythrum salicaria) having long spikes of purple flowers. It has become naturalized in the United States and is frequently treated as a noxious weed
marsh herb with a long spike of purple flowers; originally of Europe but now rampant in eastern United States