Sunday, February 14, 2010

Pigweed

What’s still green: Arborvitae, juniper and other evergreens, some rose stems, cholla, prickly pear, yuccas, grape hyacinth, Japanese honeysuckle faded, vinca, buried sweet peas, coral bells, some sea pink leaves, buried snapdragons, beard tongues, pink and yellow evening primroses, purple asters, buried chrysanthemums, cheat grass. One man pruning his apples yesterday, another repairing a fence, a third repairing his drive.

What’s grey, blue-grey or grey-green: Piñon, pinks, snow-in-summer, yellow alyssum, saltbush, winterfat.

What’s red: Saint John’s wort.

What’s yellow: Weeping willow and forsythia branches.

What’s blooming inside: Christmas cactus and aptenia; new leaves on chaste trees, miniature pomegranates and bougainvillea.

Animal sightings: Large robin standing by side of road; sounds of water fowl yesterday.

Weather: Snow dusting Monday; mud finally began to dry Friday; 10:52 hours of daylight today.

Weekly update: A few months ago, someone down the road cut the weeds growing by the road and left a great heap of dried Russian thistle and pigweed. That pyre of dead litter’s still there, protecting seeds that will be free to fly with the spring winds to perpetuate themselves on someone else’s land.

I eye it malevolently whenever I pass. Russian thistles not only scratch my hands when I touch them, but produce a grey yellow smoke that attacks by lungs when I get too near.

Pigweed is worse. Its male and female flowers must be pollinated by wind. Last year they began blooming around the first of August, and within four days my eyes were sticky. A week of so later, I was sneezing, had a runny nose and irritated eyes.

When I first moved here, I used an antihistamine until my ophthalmologist told me my pressure readings were reaching glaucoma levels. The readings are still high a decade after I stopped using any medication and let my nose run. When my eyes burn, I learned eye drops were more effective on the outside of my lids than in my eyes.

Pigweed is a generic term for members of the Amaranth family that share many of the same characteristics. In the early twentieth century, Elmer Wooton and Paul Standley described 13 species in the state, and indicated the most common were mat pigweed (Amaranthus blitoides), redroot (retroflexus) and powellii. At the time, smooth amaranth (hybridus) was found in the San Juan valley, while careless weed (palmeri) grew in the south.

I believe the one growing in my yard is white or tumbleweed pigweed (albus), which was also "common throughout the State" then and was "commonly seen along the fences, where they are associated with the Russian thistle and bugweed."

In summer, thin branches sprout from the upper leaf joints with inconspicuous male and female flowers that space out as the panicle extends several inches. In many places the feathery pyramidal plants form hedges against the fences that look like so many Christmas trees for sale.

Once each female has produced a seed, the extraneous parts fall away, leaving dark knobs on bare, bleached out, woody stalks. Eventually, the wrinkled skins protecting the reddish-brown seeds will split and the increasingly brittle stalks will break, leaving the wind to carry both away. If strong winds don’t appear, the seeds fall near the parent, and the plants disintegrate into mulch.

My eastern neighbor’s yard became a sanctuary when he leveled his land and put in a septic field. I first pulled out offending plants, but the roots brought out so much dirt I realized I had not only created a new place for seed, but had also just shaken some loose that now was waiting to be covered by the wind.

When pigweed emerges, it appears as a small, grey fuzzy rosette with a tiny white root. My uphill neighbor’s yard shimmers with them in the summer. I tried pulling them, but there were so many my wrist sent warnings of carpel tunnel damage.

I next decided it was time to see if the much publicized Round-up would work. I discovered that while it killed mature plants, it didn’t vaporize them. The area smelled of rotting vegetation for weeks that still had to be cut down.

The other problem with Round-up is many varieties of pigweed have developed a resistence to the active ingredient, glyphosate. The more I sprayed, the more likely I would produce survivors that were stronger than their ancestors.

Then I tried a weed-eater. When pigweed thrives it can get more than 6' tall and the stalks can be several inches in diameter. After burning out several motors, I found the brush cutters. When I would cut one down, it would rain on me. I don’t know if it was seeds, pollen, or dead leaves, but it didn’t matter to my allergic imagination.

Others use bigger machines with no more success. The men who maintain the roads mow plants when they get tall enough to obstruct drivers’ vision, but they leave the debris to protect the hidden seed bank. Some take a blade and scrape away everything on the shoulder, leaving bare ground for next year’s seeds to colonize.

Last summer, several plowed their land in late April, when pigweed was first emerging, but planted nothing. They’d probably been told, steel teeth deprive the turned-up roots of moisture and expose the seed to incandescent light that suppresses germination. However, they also buried other seeds. Heat and darkness can reverse the effects of light and recondition the newly buried seed.

Some plowed again in late July, just before it rained. New plants germinated within days. By then, the winds had returned to blow away any loosened dirt and seeds.

You can’t follow city rules and bag your weeds for trashmen to haul away: a single pigweed or Russian thistle will fill a bag. Last August I passed two pick-ups headed for the dump with uncovered beds filled with pigweed and Siberian elm saplings.

You have no choice. You have to burn. Only, you can’t burn a field of pigweed. By the time it’s dry enough to ignite, the leaves are gone and there’s too much air. You have to collect it in a pile like the one down the road. Even then, it won’t burn unless you crush it down with a shovel or pitchfork. I used to use a small piece of particle board I could walk on.

Several years ago my west side neighbor tried just lighting a match. Nothing happened. Then he tried barbeque light fluid. Still nothing happened. Try as he might, he couldn’t get the open pile to stay lit.

Pigweed has its ways, and outwits those who refuse to study its rules.

Notes:Chadoeuf-Hannel, Regine and Ray B. Taylorson. "Enhanced Phytochrome Sensitivity and Its Reversal in Amaranthus albus Seeds," Plant Physiology 78:228-231:1985.

Wooton, Elmer O. and Paul C. Standley. Flora of New Mexico, 1915, reprinted by J. Cramer, 1972.

Photograph: Dead pigweed hedge along a farm fence near the main road, 12 February 2010.

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