Alyssum simplex

What’s blooming in the area: Moss, Siberian elm, apricot, crabapple, first red tulip, daffodil, tansy and purple mustards, Alyssum simplex, dandelion; hoary cress in bud; village ditch running.

What’s coming out: Bradford pear, heath aster.

What’s blooming in my yard: Forsythia, hyacinth, puschkinia; buds on sand cherries and yellow alyssum.

What’s coming out: Apples, purple leaf plum, daffodil, large leaved soapwort, tansy, Saint John’s wort, cut-leaf coneflower; catalpa dropping its pods.

What’s blooming inside: Aptenia, bougainvillea.

Animal sightings: Birds.

Weather: Mornings still in mid-20's; high winds midweek; last rain 03/23/09; 12:53 hours of daylight today.

Weekly update: Environmentalists divide the natural world into natives and exotics. At one level, the latter includes all plants that didn’t evolve on this continent. More expansively, the aliens include any plant that arrived from another part of the country.

By these definitions, the only humans who belong are native Americans. The problem is that the rest of us, the members of the out group, recognize that we arrived in waves, and know some have been here longer than others. Xenophobes use the word alien to distinguish the newer migrants from the older ones.

When you or I look at an area of grass we damaged to lay a gas or water line, we see weeds that have invaded. To us, they are all contemporaries because they arrived on our land at the same time.

However, the purple mustard has only been expanding since the introduction of Round-up Ready seeds, and represents a major change in farming methods, while Russian thistles came in a sack of flax seed from Europe in 1886. They not only reference the migration of Mennonites from the Ukraine to South Dakota and the growth of the railroads, but signify the transformation of the northern Great Plains by winter wheat and the concomitant improvement in the American diet.

There’s a small yellow alyssum blooming near the narrow arroyo that has a similarly layered past. Something explains how it came to be growing on the shoulder in front of one house that lies below the road, while the wind or currents from passing cars explain the patch on the other side of the pavement.

Alyssum simplex is clearly not a native. It grows in the drylands from Iberia to Iran and farther east to westernmost China, and in northern Africa across the Straits of Gibralter. If one only looked at the dates on the USDA website, one would see the first report was in Wyoming in 1977, and there were reports in the 1980's from Nevada, Utah, Colorado and New Mexico. It appears to be the stereotypic invader, coming from a distant land, perhaps some Balkan or Asian military base, then disbursing rapidly to the Four Corners, then east into New Mexico.

Everything about the annual is insignificant. The four petals measure a sixteenth to an eighth inch in length, open a few weeks this time of year, and are more obvious in the afternoon than in the morning. Failure to observe the tiny flowers that first appear scattered on the rims of concave disks buried in similarly colored, clasping leaves, may be an understandable oversight.

The two to seven-inch horizontal stalks that branch from the base will die by the end of May, leaving barely a trace by the time botanists, released from school, go looking for wildflowers in summer. Field guides rarely contain the hard to see, and changing names are always a challenge. Until recently, the mustard family member was known as Alyssum minus and has never gotten a common name.

If one looked at maps, rather than publication dates, one could argue the dull, reddish-brown seeds were here before México expelled the Spanish in the 1820's, and that they arrived in something imported from that country. The current USDA map shows it growing in northwestern New Mexico in Rio Arriba county, west in San Juan, south in Sandoval and McKinley County to the southwest.

Spanish settlement spread slowly in the eighteenth and early nineteenth centuries from the Española valley up the Rio Grande and its major tributaries as population increased, then filled in and settled the smaller rivers. After the American military subdued the Ute in the 1850's, families moved up towards the end of the rift valley into the San Luis Valley of southern Colorado. From there, men moved east and west looking for temporary jobs.

The map John Kartesz published this year shows the dense, hairy leaves appear in the shadow of those settlers, but he also indicates that once they found places to naturalize, they followed a separate colonization path. In New Mexico, they’re now reported in all the counties that border Colorado, and Gene Jercinovic has seen them in the Manzanos near Albuquerque.

Colorado is their promised land. Writing about the Great Plains in 1986, William Barker only reported the quarter-inch flat seed pods in Huerfano County, the other end of the old Denver and Rio Grande Railroad, and two counties around Denver, Arapaho and Douglas. Today, it grows everywhere, except the central corridor that leads to Denver, and "carpets large areas of fields and roadsides in the very early spring" in the San Juan valley, the other side of the Continental Divide from the San Luis.

Wyoming, where it was first reported, is close to the northern end of its range, but the white taproots are happy as far west as the eastern edge of Utah and deep into northeastern Arizona. They skipped over more arid lands to prosper in some counties in northeastern California and contiguous part of Oregon.

The plant not only needs some minimum level of moisture, but people studying the Lastoka Prairie in Boulder County, Colorado, discovered it dies out when nitrogen and phosphorous are removed from the soil by carbon and gypsum.

If one believes the chronology, it’s an aggressive invader exploiting ecological changes like the death of the aspens and the underground diversion of water from the San Juan to the Rio Grande. If one looks at the geography, it may have lived here for centuries, invisibly entwined with Spanish-speaking settlers who may still seem exotic to Anglos, but no longer are alien.

Notes:
Barker, William T. "Brassicaceae Burnett, the Mustard Family," in Great Plains Flora Association, Flora of the Great Plains, 1986.

Dewey, L. H. The Russian Thistle and Other Troublesome Weeds in the Wheat Region of Minnesota and North and South Dakota, 1893, cited by USDA Forest Service, Range Plant Handbook, 1937, republished by Dover Publications, 1988.

Jercinovic, Gene. "Alyssum minus," New Mexico Flores website.

Kartesz, John. "Alyssum simplex Rudolphi," USDA Natural Resources Conservation Service, Plant Profiles website.

_____. Floristic Synthesis of North America, 2010, reprinted by Al and Betty Schneider.

LeJeune, Katherine D., Katharine N. Suding and Timothy R. Seastedt. "Nutrient Availability Does Not Explain Invasion and Dominance of a Mixed Grass Prairie by the Exotic Forb Centaurea diffusa Lam.," Applied Soil Ecology 32:98-110:2006.

Schneider, Al and Betty. "Alyssum parviflorum," Southwest Colorado Wildflowers, Ferns and Trees website.

Photograph: Alyssum simplex, covered by roadside dust, growing near the narrow arroyo, 4 April 2010.