Rangeland Rehabilitation: In Defense of Weeds

Weeds, the ubiquitous unwanted plants.  Their characteristics such as rapid growth and spread, combined with their ability to colonize disturbed environments make them the bane of many land owners.  But there is an upside to weeds, especially if working to rehabilitate former rangeland such as the grassland restoration project at the Painted Pony Resort.  Local Plamer's pigweed or Amaranthus palmeri grows on the estate and particularly likes the lowest sections of the river bottom where it can be found in large swaths during the monsoon season.  Native to the southwest and edible, its' ability to quickly convert soil nutrients into biomass results in rapid growth and combined with the ability to sequester excess nitrogen makes it ideal for topsoil barriers construction (no additional fertilizer required).  Since pigweed may be toxic to cattle because of the nitrates in the leaves, it is an undesirable species in the restored grasslands of the riverbed so an alternate use for this plant was sought.  The previous years test barrier experiments with local pigweed resulted in new grass along the test barriers (see last image), so this was expanded to include additional areas on the estate.  Pigweed in the river bottom was harvested with the rake on the tractor.  The material was then transported up onto the benches along the riverbed and distributed in rows perpendicular to the dip (parallel to the San Simon riverbed) allowing the biomass to collect wind and waterborne sediment and additional seeds.  This micro-habitat will in turn support new grass next season.  The new grass will continue to slow water on the landscape allowing time for more water to soak into the ground which will in turn support more grass, creating a cycle which will eventually rebuild topsoil and return the landscape into desirable grasslands.  So what is considered a nuisance by some has an important use on the estate and is one more way to use what the land produces to help restore other areas.

Collecting Amaranthus palmeri from the San Simon riverbed
Clearing pigweed in the river bottom
Several hundred feet of topsoil restoration barrier in place.
A pigweed barrier from last year with new grass on barren soil.


  1. We just had tall Amaranth on our hike last week and we're fighting it in our "yard" too. Hubbie is allergic to the flowers when mature. Amaranth is a much 'nicer' name than pigweed, or some locals call it Careless weed because it "cares LESS where it grows!"

  2. I agree that Amaranth is a much nicer name for the plant and have also seen the name careless weed to describe the species. But the plants advantages in restoration work are great. Primarily its ability to rapidly create biomass which I'm transporting to barren eroded areas of the estate to encourage new grasses. Last years experiment worked well so I've expanded the project this year and the restoration work is already producing results. I see many more birds in the riverbed now and saw my first western tanager the other day in a big mesquite where I was harvesting the Amaranth. The doves and quail have increased in numbers and I routinely hear and see hawks hunting in the riverbed. I suspect if native grazers do not move in and start eating the grasses they will have to be cut.

  3. I should also point out that using Amaranth as a topsoil restoration barrier does not create more Amaranth the next season. By late monsoon only a couple of Amaranth plants had sprouted along last years barriers created out of the material. New grass (Tobosa grass) made up the majority of new growth along the barriers.