Drought and Snakeweed

Weather: Dry, with only a wetting on 9/4.

What’s blooming in the area: Hybrid tea roses, buddleia, silver lace vine, trumpet creeper, datura, morning glories, sweet pea, alfalfa, Russian sage, annual four o’clock, bouncing Bess, Sensation cosmos, African marigolds, coreopsis, zinnias.

Beyond the walls and fences: Goat’s head, bindweed, green-leaf five-eyes, yellow and white prairie evening primroses, leather leaf globe mallow, green amaranth, pigweed, native sunflower, gumweed, goldenrod, áñil del muerto, Tahoka daisy, golden hairy asters.

In my yard: Yellow potentilla, garlic chives, calamintha, lead wort plant, larkspur, winecup mallow, pink evening primrose, scarlet flax, Maximilian sunflowers, Mexican hat, black-eyed Susan, chocolate flower, blanket flower, bachelor button, Mönch aster, yellow cosmos.

Bedding plants: Sweet alyssum, snapdragon, marigold, gazania.

What’s blooming inside: Zonal geraniums.

Animal sightings: Small birds, geckos, cabbage butterflies, bumble bees, grasshoppers, ants.

Weekly update: Drought is a progressive condition, or perhaps I should say, a retrogressive one. If the intervals between dry spells aren’t long enough for vegetation to recover, each one makes conditions worse.

Say, for example, a drought kills 5% of the vegetation, and 2% recovers. When the next drought destroys another 5%, that’s 8% gone.

New Mexico had severe droughts in the 1930s and again in the 1950s. The Santa Cruz reservoir went dry in 1956. More dry years occurred in the late 1970s. It may have been wet after that, but damaged grasslands didn’t recover enough to survive the recent bad years.

My front yard was in poor condition when I came here in 1991. All the slope supported was ring muhly grass, winterfat and broom snakeweed.

When we had some dry years around 2007, the ring muhly died. Broom snakeweed colonized areas where water seeped from beds I was watering. I left the upland undisturbed, and so it remained impervious to weed seeds.

We had a very bad year in 2012, when water was severely rationed by the ditch managers. Needle grass on local grasslands suffered. Russian thistles invaded the next spring. The land to the south and west of me was devastated for the first time since I’ve been here.

Last year, the carcasses blew in the wind, and water was still rationed. However, there was just enough rain to revive the dead crowns.

Nothing much happened in my yard in 2014, but we had rain this year in late spring and mid-summer. My previously barren ground sprouted Russian thistles everywhere. They didn’t come from those carcasses, but from seed blown off the land to the south and west. It had been an aerial assault.

Elsewhere, broom snakeweed appeared everywhere in late summer on hillsides that had lost some of their cover. Some had continued to be grazed a few weeks a year by horses

but other parts haven’t been grazed in the last 20 plus years.

Some experts point to the yellow flowered shrub as an indicator of land abuse. Others note, when it’s invading it slows or prevents soil erosion. It’s part of nature’s repair kit when things go awry.

Notes: Broom snakeweed is Gutierrezia sarothrae. Russian thistles are Salsola pestifer. Ring muhly is Muhlenbegia torreyi. Winterfat is Eurotia lanata. Needle grass is Stipa comata.

Tirmenstein, D. "Gutierrezia sarothrae," 1999, in United States Forest Service, Fire Effects Information System, available on-line; summarizes research on the composite.

Photographs:
1. Broom snakeweed in my yard, 12 September 2015.

2. Snakeweed floret, 12 September 2015.

3. Front yard before it was destroyed by drought, 26 August 2006. The purple haze is ring muhly grass. The grass in front is black grama. Winterfat is the gray shrub in back.

4. Front yard two years later, 2 August 2008. The gray rings in front are the dead muhly. The rest is winterfat.

5. Local prairie after the drought killed the needle grass (the black clumps) and Russian thistles had invaded (the green), 24 August 2013.

6. Local prairie with the needle grass reviving, and the Russian thistle carcasses blown away, 20 March 2014.

7. My front yard this year, after those seeds from the local prairie landed, 6 September 2015. The rust is Russian thistle, the yellow is broom snakeweed, and the gray is winterfat.

8. Area hillside covered with broom snakeweed, 10 September 2015.

9. Arroyo flood plain across the road from the hill in #8, 10 September 2015.

10. Same flood plain as #9 before most recent dry years, 2 November 2011.

Muhly Ring Grass

What’s blooming in the area: Roses, Apache plume, silver lace vine, buddleia, honeysuckle, canna, datura, Heavenly Blue morning glory, narrow leaf globemallow, white sweet clover, yellow evening primrose, lamb’s quarter, Russian thistle, pigweed, chamisa, broom snakeweed, winterfat, Tahokia daisy, Maximilian and native sunflowers, áñil del muerto, ragweed, gumweed, wild lettuce, broom senecio, golden, heath and purple asters; catalpa beans, hay cut.

What’s blooming in my garden, looking north: Golden spur columbine, hartwegii, nasturtium, chocolate flower, blanket flower, coreopsis, Mexican hat, black-eyed Susan, yellow cosmos, chrysanthemum.

Looking east: Fashion rose, garlic chives, pinks, rock rose, sweet alyssum, winecup, hollyhock, California poppies, Crackerjack marigolds.
Looking south: Rose of Sharon, rugosa rose, Crimson Rambler morning glory, Sensation cosmos, zinnia.

Looking west: Caryopteris, Russian sage, catmint, leadplant, ladybells, purple ice plant, Monch aster.

Bedding plants: Sweet alyssum, snapdragons, petunia, Dahlberg daisy.

Inside: Aptenia, zonal geranium.

Animal sightings: Quail, gecko, ants, bees.

Weather: Rain Sunday, Friday and yesterday, prairie wet deeper than my shovel; frost on car windows Thursday morning; low hanging, full moon before dark on Wednesday.

Weekly update: We finally got rain last week, and now the habitues of late summer have resumed growing, racing to produce seed before it gets too cold.

The rains began last Monday. Áñil del Muerto germinated last Saturday, and put out its second leaves two days ago. There was sun on Monday and Muhly ring grass showed some green that afternoon, as did the black grama and needle grasses. Downy chess grass sprouted in the drive.

Muhly is one of the grasses that colonizes land denuded by overgrazing. It’s palatable in early spring when it’s growing, but goes dormant in the heat of the summer and turns dry and harsh. When the monsoons appear, it regreens to send up short purple culms with seeds that are also unappetizing.

Not only is it well armed against herbivores, but it also adapts to scarce water. The perennial begins as a small round tuft. Over the years, the tuft turns into an inch or two greyish white wide band that expands outward, leaving an ever widening doughnut opening. When it greens up, it begins on the outer faces, where seeds form. In relatively flat areas, its new growth appears on all sides; on more sloping land ring muhly greens on the downhill or wet side first.

When I see it spread across the top of my south facing slope, I wonder if it prevents or abets erosion by stopping or channeling the flow of water. The recent rains have been able to sink into the ground, instead of rolling downhill. The ring, or its shadow, acts as a small reservoir where other seeds plant themselves and its shallow tenacious, fibrous roots hinder the wind.

The 2" high grass’s life cycle is heavily dependent on rainfall. During the droughts of the past few years, it all but died out, and snakeweed invaded its territory. With last year’s rains, it came back in the area where the needle grass had died, but didn’t try to resettle the area with the broom.

Frederic Clemens believed the order of succession on damaged arid lands was annual grasses, short perennial grasses, bunch grasses with ring muhly, and, finally, the original gramas. Others have since found grasslands rarely get beyond the needle and rice grasses, and that factors like weather and soil influence the progression.

Even if my uphill neighbor hadn’t told me he had worked for the ranch that owned this land before he settled on its perimeter, the mere presence of Muhlenbergia torreyi could have told me. I don’t know if it was cattle or sheep, but the remains of animal chutes near the old road bed don’t look wide enough for full-grown cows.

What I don’t understand is why it only appears on the upward side of my house, and why the lower land and much of the surrounding prairie are predominantly needle grass. I’m guessing there could be differences in the quality of the soil, or that area near the ranch perimeter may have been trampled more and the compacted soils less porous, less receptive to water.

It does appear the grass can’t compete with other vegetation, and that it dies out when either the bunch grasses or the scrub seed themselves. It also doesn’t like being crushed and cracks when it’s stepped on during its dormant phases. It would appear to be the first thing to disappear when humans or animals appear. While it seems common enough, in fact, in this area, its period of existence is limited by both humans and nature.

Notes:
Clements, Frederic E. Plant Succession and Indicators: A Definitive Edition of Plant Succession and Plant Indicators, 1928, discussed by Debra P. Coffin, William K. Lauenroth and Ingrid C. Burke, "Recovery of Vegetation in a Semiarid Grassland 53 Years after Disturbance," Ecological Applications, 6:538-555:1996.

United States Department of Agriculture, Forrest Service, Range Plant Handbook, 1937, republished by Dover Publications, 1988.

Photograph: Muhly ring grass, 29 September 2007.