Sunday, September 30, 2012

Purple Loosestrife


Weather: Sporadic afternoon showers and cool mornings with high humidity; last rain 9/128/12; 11:51 hours of daylight today.

What’s blooming in the area: Hybrid perpetual roses, silver lace vine, datura, Heavenly Blue morning glory, African marigolds, zinnias.

Beyond the walls and fences: Leatherleaf globemallow, white and pink bindweeds, goat’s head, yellow and white evening primroses, snakeweed, native sunflowers, áñil del muerto, Tahoka daisies, heath, purple and golden hairy asters.

In my yard, looking east: Maximilian sunflowers.

Looking south: Floribunda and miniature roses, crimson rambler morning glory.

Looking west: Calamintha.

Looking north: California and Shirley poppies, nasturtium, chocolate flower, blanket flower, black-eyed Susan, Mexican hat, chrysanthemum, yellow cosmos.

Bedding plants: Snapdragons.

What’s blooming inside: Zonal geraniums, aptenia, petunias.

Animal sightings: Small brown birds, geckos, bumble bees, other bees, hornets, harvester and small black ants.

Weekly update: Purple loosestrife is to water what bindweed is to land: a tomato that will eat Chicago.

Lythrum salicaria has gobbled acres and acres of wetlands in Michigan, Wisconsin and Minnesota, changed the flows of water, displaced native plants including cattails and left little of value for frogs and salamanders.

The flowers are striking. I remember the first time I saw them about 1955 or 1956. My mother was driving some country road hunting for wild flowers when we saw a mass of rosy purple in what looked like a backwater from some creek feeding the Kalamazoo river. The late summer color against the browns of marshes and the never ending corn of the farm land was captivating.


Nurserymen responded to the threat of banishment as a noxious weed by developing sterile hybrids in the 1990's. Only, Kimberly Ottenbreit has found some of the cultivars produce seed that fertilizes the wild plant. Earlier researchers had found bees and other insects had already crossed the European import with native Lythrum species to enhance purple loosestrife’s ability to survive the wide range of new world environments.

Daniel Thompson and his colleagues believe the spread of the plant occurred in two phases. It grows along European estuaries, where sand was dug to ballast sailing ships. Edward Voss says it was already in Michigan in 1837 when Douglass Houghton surveyed the state’s mineral wealth. The perennial spread along the canals in New York and Ohio, but Thompson’s group believed dust sized oval seeds stayed within the region carved by the retreat of the last glaciers.

Things changed dramatically in the 1930's. Camille Rousseau found reports from 1865 that French settlers had brought the medicinal herb to Grosse Ile, near Montmagny. In the 1930's the reddish square stems suddenly began invading the pastures along the river’s flood plain. One possible explanation is that farmers were using more fertilizers whose run off enriched the shallows with nutrients that stimulated this plant at the expense of others. More seeds were produced that travel by water and can remain viable for at least two years.


It’s always tempting to blame the Saint Lawrence Seaway that opened in 1959. However, it had already spread along the lake shores of Michigan where lumber carriers had docked in the nineteenth century, with the earliest reports coming from Muskegon in 1879. The early ones had been sailing ships. It also spread through the inland counties like mine where small lakes had formed in glacial depressions. The change from manure to other forms of fertilizer in the 1950's probably did the rest.

Thompson’s team also reported it spread into the arid west in the 1930's with the promotion of large scale irrigation programs, though it wasn’t as aggressive as it was in the Great Lakes area. However, while it now is reported in most of the country, it is spotty in this area. The USDA map for New Mexico shows it in Bernalillo and Grant counties. In Colorado, it’s concentrated in the area from Denver north. Arizona is one of the few states with no reported colonies.


I hate to break the news, but it’s growing with the cattails on the south side of the Griego bridge here in Española. Lord knows how it got there, but there is no mistaking the tall spikes when you see them. I suppose somewhere someone ordered some plants from a nursery that allowed it to jump the mountains.

Notes:
Ottenbreit, K. A. The Distribution, Reproductive Biology, and Morphology of Lythrum Species, Hybrids and Cultivars in Manitoba (1991); cited by Urbatsch.

Rousseau, C. “Histoire, Habitat et Distribution de 220 Plantes Introduites au Québec,” Naturaliste Canadien 95:49-169:1968; cited by Thompson.


Stackpoole, Sarah. “Purple Loosestrife in Michigan,” Michigan Sea Grant bulletin E-2632, 1997.

Thompson, Daniel Q., Ronald L. Stuckey, Edith B. Thompson. “Spread, Impact, and Control of Purple Loosestrife (Lythrum salicaria) in North American Wetlands,” U. S. Department of the Interior, Fish and Wildlife Service, research report 2, 1987.

Urbatsch, Lowell. “Purple Loosestrife,” U. S. Department of Agriculture, Natural Resources Conservation Services plant guide, 2002 revision.

Voss, Edward G. Michigan Flora, volume 2, 1986.

Photographs: Purple loosestrife growing with cattails south of the Griego Bridge in Española, 15 August 2012.

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