
Photo by
urbpan. Location: Leverett Pond, Olmsted Park, Brookline.
Urban species #200: Purple Loosestrife
Lythrum salicariaHandily winning the award for "prettiest scourge ever" is the invasive species poster plant purple loosestrife. An uncommonly attractive marsh plant that forms dense patches of stunning purple blossoms, it prevents native plants from growing. This reduces bird habitat, especially of marsh nesting birds such as rails and
red-winged blackbirds. Even native insects are deprived of food when this invader takes over (though a few species of
butterflies and
bees feed on the flowers' nectar). Native to Eurasia, it now occurs around the world in dozens of far-flung places where growing conditions are suitable. Several attributes account for this plants' success as an invader, and as an urban species. It can tolerate a wide range of moist soil conditions, and is uncommonly hardy, some stands persisting for decades without diminishing. It reproduces both with the production of enormous amounts of seeds (which can be dispersed by
birds, not because the birds eat the loosestrife's fruit, but because the tiny thin seeds can cling to their feathers) and through vegetative spread. Trampling, incomplete pulling, and other injuries to the plant only serve to accelerate its spread. Human disturbances to the soil favor the growth of purple loosestrife. Occasionally it can be found growing away from the water in urban areas.
( I took a lot of pictures of it. )