Rio Grande County Weed District

Summer hours (May to Sept)- 7:00 am to 5:00 pm Mon- Fri

Winter Hours (Oct- April) - 7:00 am to 4:00 pm Mon - Thursday

Closed on weekends and major holidays

Brianna Brannon
0164 W county Road 3 North
Monte Vista CO 81144

Cell: 719-580-0089
Phone: 719-852-4804

Who are we

Frequently Asked Questions

What do I, as a land owner, need to know?

All noxious weeds on your porperty must be visually (mown or sprayed) controlled BEFORE FLOWERING STAGE.

If you are a "Sensitive Person" to herbicides, you must register at: https://www.colorado.gov/pacific/agplants/pesticide-sensitive-registry-facts 

ALSO, you are still responsible for controling the noxious weeds on your property.

What do I, as an Organic Farmer or Bee Keeper, need to do?
What resources are available to me?

Job Openings for 2017 Growing Season

If you are interested, please download and apply for the following:

  1. Weed Inspector
  2. Weed Sprayer Technician

What we do

Rio Grande County Weed District is one of the only true "Weed Districts" in the San Luis Valley that is operational. Operational meaning, the weed district supervisor contacts those with private land containing noxious weeds and provides resources and weed managment plans to assist with meeting the control requirements set forth by the State of Colorado, and benefit for not only the land owner but for the whole of the county.

History

The Rio Grande County Weed/ pest District was formed by the request of local farmers who were concerned with the health and economics of the agricultural lands within the county due to the invasive noxious weeds that were taking over. In 1963 the county was split in three districts that were in charge of controling noxious weeds within those districts(Drake pg.1). In 1970 the three districts merged into one weed and pest district for the service of all Rio Grande County. In 1990 the State of Colorado issued the Noxious Weed Act which defined that,  "Noxious weeds have become a threat to the natural resources of Colorado, as thousands of acres of crop, rangeland, and habitat for wildlife and native plant communities are being destroyed by noxious weeds each year." 35-5.5-102. Legislative declaration(1.5)(a) To this day Rio Grande County Weed District strives to control noxious weeds through intergative processes and partnering with other entities.  

Noxious Weed Fact Sheet

PLEASE NOTE: These are only a few of the noxious weeds that are controlled in the Rio Grande County, for additional weed information please contact the weed district at 719-852-4804 or email us!

Canadian Thistle
Canadian Thistle
Canada thistle (Cirsium arvense) is a non-native, deep-rooted perennial that spreads by seeds and aggressive, creeping, horizontal roots (rhizomes) that can grow 15 to 30+ foot in depth. Canada thistle can produce about 1,000 to 5,000 seeds per plant that can survive in the soil for 20 years or more. Typically, it reproduces vegetatively about 6 foot in a season through a creeping root system, and can quickly form dense monotypic stands. Every piece of root, from 2 cm in length, is capable of forming new plants.
Hoary Cress
short white topHoary Cress
Hoary Cress is a non-native deep rooted perennial that thrives in a wide range of soil types. They grow to two foot tall and are extremely invasive. Hoary Cress reproduces via both seed and root, with root being the primary reproduction source. One plant can produce from 1,200 to 4,800 seeds per plant with a soil seed bank life of three or four years. Within three weeks of germination the seed produces new rosettes which emerge within 3 ½ weeks and root shoots that have been documented to grow as fast as approximately 4 ft in a season. A single plant can produce 450 new shoots in a single growing season.
Perennial Pepperweed
tall white topPerennial Pepperweed
Hoary Cress is a non-native deep rooted perennial that thrives in a wide range of soil types. They grow to two foot tall and are extremely invasive. Hoary Cress reproduces via both seed and root, with root being the primary reproduction source. One plant can produce from 1,200 to 4,800 seeds per plant with a soil seed bank life of three or four years. Within three weeks of germination the seed produces new rosettes which emerge within 3 ½ weeks and root shoots that have been documented to grow as fast as approximately 4 ft in a season. A single plant can produce 450 new shoots in a single growing season.
Black Henbane
Black Henbane
Black Henbane is an annual / Biennial with a long tap root and reproduces only by seed, but produces approximately 100,000 to 500,000 seeds per plant. Seeds are known to last approximately 5 years in the soil. Black henbane is an opiate and all parts of the plant are poisonous andpotentially lethal to humans and livestock. The plant and seeds have been used as a hallucinogenic and theflowers and give off an odor that causes a kind of “high”.
Russian Knapweed
Russian Knapweed
Russian Knapweed develops on many soil types, is very drought tolerant and is known to have allelopathic properties. Russian Knapweed is reported to have lethal effects on livestock due to its uptake of Zinc in the soil. The plant reproduces primarily through root system and fragments of one inch or less can reproduce into a new plant from depths of six inches. Russian Knapweed also reproduces via seed in small quantities, survival of seeds are from 3 to 5 years in soil bank, and new growth by seed is uncommon.

Resources used

Montana University Extension: http://store.msuextension.org/publications/AgandNaturalResources/MT201005AG.pdf

DiTomaso, J.M., G.B Kyser at al. 2013. Weed Control in Natural Areas in the Western United States. Weed Research and Information Center, University of California.

Colorado State University: http://extension.colostate.edu/topic-areas/agriculture/noxious-weeds-invasive-plant-species/

Colorado Department of Agriculture: https://www.colorado.gov/pacific/agconservation/canada-thistle

Whitson, T. (2006) Weeds of the west. Jackson, WY: Grande Teton Lithography

Merrill A. Ross : https://www.btny.purdue.edu/Pubs/WS/CanadaThistle/CanadaThistle.html

Effective Control of Noxious Weeds

Canadian Thistle

Mowing – is effective if mown every 20 days for the full growing season for several seasons
Grazing- In the spring with fall application of herbicide
Herbicide- Is effective for thistle eradication, but only if followed by these specific steps:
  1. 2,4-D in the spring to keep from flowering
  2. Application of Translocation herbicide with sticker adjuvant in fall
  3. Repeating this for at least three years
  4. Reseeding in Fall the second year of control to re-establish desired grasses and/or forbs

WHAT NOT TO DO

SHOVEL, DISC, TILL, or HAND PULL