HomeMy WebLinkAbout1.08 Exhibit G(2) - Weed Management Pln
February 23, 2026
Noxious Weed Management Plan
Mitchell Creek Community
Garfield County, Colorado
Prepared for:
The Land Studio, Inc. Mitchell Creek Community
365 River Bend Way 50235 US-6 West
Glenwood Springs, CO 81601 Glenwood Springs, CO 81601
Prepared by:
Red Mountain Environmental, LLC.
802 Palmer Avenue
Glenwood Springs, CO 81601
Mitchell Creek Community Weed Management Plan
Table of Contents
1.0 Summary ............................................................................................................................................. 1
2.0 Description of Survey Area ................................................................................................................. 1
3.0 Results of Survey Efforts ..................................................................................................................... 5
4.0 Noxious Weed Management Recommendations .............................................................................. 5
List of Figures
Figure 1 – Project Vicinity ............................................................................................................................. 3
Figure 2 – Proposed Development ............................................................................................................... 4
Appendices
Appendix A – Colorado Listed Noxious Weeds .............................................................................. 7
Appendix B – Garfield County Listed Noxious Weeds ................................................................. 10
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1.0 SUMMARY
The Mitchell Creek Community project is proposing to redevelop the Ami’s Acres Campground
under a Planned Unit Development application, to provide a single-family home community with
approximately 97 home sites. The development would require complete site regrading, and
would also include new utility corridors for electric, water, and sewer to each lot. Home sizes will
range from 1,312 square feet to 2,607 square feet, with on-lot parking (either surface parking or
in a garage). New water and sewer lines would run from west Glenwood Springs along US Highway
6 (US-6) to the development. The new community would no longer offer camping or other
temporary accommodations.
This Weed Management Plan was prepared at the request of The Land Studio and Mitchell Creek
Community, to fulfill the submittal requirements of a Major Impact Review for a Planned Unit
Development and Sketch Plan application.
A site visit to document the presence of noxious and nuisance weed species was conducted in
January 2026. Given the time of year of the site review, noxious weeds which were easily visible
and identifiable were noted but not mapped. Both Garfield County’s noxious weed list and the
State of Colorado’s noxious weed list will be utilized for further survey efforts (Appendix A and B).
2.0 DESCRIPTION OF SURVEY AREA
The project is situated in the Sedimentary Subalpine Forests (21e) level IV ecoregion, which is
within the Southern Rockies (21) level III ecoregion (Chapman et al. 2006). The elevation of the
project area ranges from 5,695 feet to 5,845 feet (msl), occurring on south-facing slopes. The
parcel lies at the western side of Section 6, Township 6 South, Range 89 West (6th Principal
Meridian; Figures 1 and 2).
Habitats within the development are mostly dominated by landscaping trees and shrubs (Russian
olive, apple, Siberian elm, etc.) and some remnant patches of native species such as oakbrush,
pinyon-juniper woodlands, mountain sagebrush, and understory grasses and forbs. Dominant
vegetation within these community types are as follows:
Pinyon-Juniper Woodlands. Within the
project area, and more commonly on the
outside of the project area, vegetation is
dominated by pinyon-juniper woodlands,
which consist primarily of pinyon pine
(Pinus edulis), Utah juniper (Juniperus
osteosperma), and patches of oakbrush
(aka Gambel oak; Quercus gambelii), with
understories of infrequent mountain
mahogany (Cercocarpus montanus), Utah
serviceberry (Amelanchier utahensis),
chokecherry (Prunus virginiana), mountain
sagebrush (Artemisia tridentata subsp.
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vaseyana), broom snakeweed (Gutierrezia
sarothrae), Indian ricegrass (Oryzopsis
hymenoides), western wheatgrass
(Pascopyrum smithii), brittle cactus (Opuntia
fragilis), and other species. Also common
are ruderal (weedy) species such as
cheatgrass (Anisantha tectorum), storksbill
filaree (Erodium cicutarium), and musk
thistle (Carduus nutans). As mentioned,
other volunteer species such as Siberian elm
(Ulmus pumila), Russian olive (Elaeagnus
angustifolia), and apple trees (Malus
domestica) are common within the existing
campground area. Many other understory
species were not identifiable given the time of year of the site visit.
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Figure 1 – Project Vicinity
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Figure 2 – Proposed Development
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3.0 RESULTS OF SURVEY EFFORTS
Houndstongue (Cynoglossum officinale), cheatgrass, storksbill filaree, plumeless thistle (Carduus
acanthoides), musk thistle (C. nutans), Russian olive (Elaeagnus angustifolia), salt cedar (Tamarix
ramosissima), and field bindweed (Convolvulus arvensis) were the most common noxious weeds
found within the project area. Myrtle spurge (Euphorbia myrsinites) is reported to also occur in
the area.
Cheatgrass and storksbill were by far the most common noxious weed and are scatted in low
densities throughout the project area. Given the time of year, more accurate assessments of weed
species presence or cover was not possible.
4.0 NOXIOUS WEED MANAGEMENT RECOMMENDATIONS
To meet the requirements of the Colorado Noxious Weed Act and Garfield County guidance, the
developer shall conduct prescribed management techniques for noxious weeds included on one of
three State weed lists: List A – designated for statewide eradication; List B – managed to prevent
further spread and, for selected species, designated for eradication in large areas; and List C – of
more localized concern, but for which the State will provide education, research, and biological
control assistance to jurisdictions that choose to manage the species. The current State list is
available in Appendix A.
If populations of List A species are present in the project area, every population shall be eradicated
prior to seed development. To stop the spread of List B species, populations of every species
designated for eradication in a particular county shall be eliminated prior to seed development.
Additionally, to meet reclamation objectives, the developer should eliminate or minimize those
noxious and invasive weeds designated as “undesirable species”. Undesirable species include
redstem filaree (Erodium cicutarium), all List C species (e.g., cheatgrass (Anisantha tectorum) and
field bindweed (Convolvulus arvensis)), and invasive species that commonly colonize disturbed or
reclaimed land and impede or prevent establishment of desirable species.
Control of invasive species is a difficult task and requires on-going control measures. Care must be
taken to avoid negatively impacting desirable plant communities and inviting infestation by other
pioneer invaders. Weed management is best achieved by employing aggressive control early on,
and persistent control efforts over several growing seasons, including direct treatments,
prevention through best management practices, monitoring of treatment efficacy, and subsequent
detection efforts.
The following methods are recommended to manage noxious weeds, per Colorado State
University’s Extension program. The Garfield County Vegetation Management Program and the
Garfield County Noxious Weed Management Plan should be reviewed for additional guidance.
Preventive:
Methods include maintaining healthy pastures, using weed-free crop seed, weed-free manure and
hay, and clean harvesting and tillage equipment, as well as the elimination of weed infestations in
areas bordering cropland, and in irrigation ditches and canals.
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Chemical:
Herbicide treatments can be highly effective and will vary based on time of year of treatment and
species treatment. Two yearly treatments would be recommended for the duration of the project,
one in spring and one in fall.
Cultural:
Methods include: Establishing and managing an adequate population of desirable vegetation to
compete with the weeds; utilizing livestock (cattle, goats, sheep) when possible; mulching; burning;
and even plastic weed barriers.
Mechanical:
Methods include: Hand-pull, hoe, mow and tillage.
Biological:
Biological weed control involves the utilization of natural enemies for the control of specific weed
species. This method can take many years to result in weed control and is often not 100% effective.
However, this method can dramatically help reduce weed densities and when combined with other
methods can be very beneficial. Methods include grazing, introduction of registered insects or
diseases. Contact the Palisade Insectary for more information.
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APPENDIX A – COLORADO LISTED NOXIOUS WEEDS
Colorado Noxious Weeds (including Watch List)
List A Species (25)
Common Scientific
African rue (Peganum harmala)
Bohemian knotweed (Fallopia x bohemicum)
Camelthorn (Alhagi maurorum)
Common crupina (Crupina vulgaris)
Cypress spurge (Euphorbia cyparissias)
Dyer's woad (Isatis tinctoria)
Elongated mustard (Brassica elongata)
Flowering rush (Butomus umbellatus)
Giant knotweed (Fallopia sachalinensis)
Giant reed (Arundo donax)
Giant salvinia (Salvinia molesta)
Hairy willow-herb (Epilobium hirsutum)
Hydrilla (Hydrilla verticillata)
Japanese knotweed (Fallopia japonica)
Meadow knapweed (Centaurea x moncktonii)
Mediterranean sage (Salvia aethiopis)
Medusahead (Taeniatherum caput-medusae)
Myrtle spurge (Euphorbia myrsinites)
Orange hawkweed (Hieracium aurantiacum)
Parrotfeather (Myriophyllum aquaticum)
Purple loosestrife (Lythrum salicaria)
Rush skeletonweed (Chondrilla juncea)
Squarrose knapweed (Centaurea virgata)
Tansy ragwort (Senecio jacobaea)
Yellow starthistle (Centaurea solstitialis)
List B Species (38)
Common Scientific
Absinth wormwood (Artemisia absinthium)
Black henbane (Hyoscyamus niger)
Bouncingbet (Saponaria officinalis)
Bull thistle (Cirsium vulgare)
Canada thistle (Cirsium arvense)
Chinese clematis (Clematis orientalis)
Common tansy (Tanacetum vulgare)
Common teasel (Dipsacus fullonum)
Cutleaf teasel (Dipsacus laciniatus)
Dalmatian toadflax, broad-leaved (Linaria dalmatica)
Dalmatian toadflax, narrow-leaved (Linaria genistifolia)
Dame's rocket (Hesperis matronalis)
Diffuse knapweed (Centaurea diffusa)
Eurasian watermilfoil (Myriophyllum spicatum)
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Hoary cress (Cardaria draba)
Houndstongue (Cynoglossum officinale)
Jointed goatgrass (Aegilops cylindrica)
Leafy spurge (Euphorbia esula)
Mayweed chamomile (Anthemis cotula)
Moth mullein (Verbascum blattaria)
Musk thistle (Carduus nutans)
Oxeye daisy (Leucanthemum vulgare)
Perennial pepperweed (Lepidium latifolium)
Plumeless thistle (Carduus acanthoides)
Russian knapweed (Rhaponticum repens)
Russian-olive (Elaeagnus angustifolia)
Salt cedar (Tamarix. ramosissima)
Salt cedar (T. chinensis)
Scentless chamomile (Tripleurospermum inodorum)
Scotch thistle (Onopordum acanthium)
Scotch thistle (O. tauricum)
Spotted knapweed (Centaurea stoebe L. ssp. micranthos)
Spotted x diffuse knapweed hybrid (Centaurea x psammogena)
Sulfur cinquefoil (Potentilla recta)
Wild caraway (Carum carvi)
Yellow nutsedge (Cyperus esculentus)
Yellow toadflax (Linaria vulgaris)
Yellow x Dalmatian toadflax hybrid (Linaria vulgaris x L. dalmatica)
List C Species (16)
Common Scientific
Bulbous bluegrass (Poa bulbosa)
Chicory (Cichorium intybus)
Common burdock (Arctium minus)
Common mullein (Verbascum thapsus)
Common St. Johnswort (Hypericum perforatum)
Downy brome, cheatgrass (Bromus tectorum)
Field bindweed (Convolvulus arvensis)
Halogeton (Halogeton glomeratus)
Johnsongrass (Sorghum halepense)
Perennial sowthistle (Sonchus arvensis)
Poison hemlock (Conium maculatum)
Puncturevine (Tribulus terrestris)
Quackgrass (Elymus repens)
Redstem filaree (Erodium cicutarium)
Velvetleaf (Abutilon theophrasti)
Wild proso millet (Panicum miliaceum)
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Watch List Species (19)
Common Scientific
Baby's breath (Gypsophila paniculata)
Caucasian bluestem (Bothriochloa bladhii)
Common bugloss (Anchusa officinalis)
Common reed (Phragmites australis)
Garden loosestrife (Lysimachia vulgaris)
Garlic mustard (Alliaria petiolata)
Himalayan blackberry (Rubus armeniacus)
Hoary alyssum (Berteroa incana L.)
Meadow hawkweed (Hieracium caespitosum)
Onionweed (Asphodelus fistulosus)
Siberian elm (Ulmus pumila)
Scotch broom (Cytisus scoparius)
Swainsonpea (Sphaerophysa salsula)
Syrian beancaper (Zygophyllum fabago)
Tree of Heaven (Ailanthus altissima)
Ventenata grass (Ventenata dubia)
White bryony (Bryonia alba)
Yellow bluestem (Bothriochloa ischaemum)
Yellow flag iris (Iris pseudacorus)
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APPENDIX B – GARFIELD COUNTY LISTED NOXIOUS WEEDS
Garfield County Listed Species (40)
Common Scientific Absinth wormwood (Artemesia absinthium)
Black henbane (Hyoscyamus niger)
Bouncingbet (Saponaria officinalis)
Bull thistle (Cirsium vulgare)
Canada thistle (Cirsium arvense)
Chicory (Cichorium intybus)
Chinese clematis (Clematis orientalis)
Common burdock (Arctium minus)
Common tansy (Tanacetum vulgare)
Common teasel (Dipsacus fullonum)
Corn chamomile (Anthemis arvensis)
Curly dock (Rumex crispus)
Cutleaf teasel (Dipsacus laciniatus)
Cypress spurge (Euphorbia cyparissias)
Dalmatian toadflax (Linaria dalmatica)
Dame’s rocket (Hesperis matronalis)
Diffuse knapweed (Centaurea diffusa)
Hoary cress (Cardaria draba)
Houndstongue (Cynoglossum officinale)
Jointed goatgrass (Aegilops cylindrica)
Leafy spurge (Euphorbia esula)
Mayweed chamomile (Anthemis cotula)
Meadow knapweed (Centaurea pratensis)
Mediterranean sage (Salvia aethiopsis)
Musk thistle (Carduus nutans)
Myrtle spurge (Euphorbia myrsinites)
Oxeye daisy (Chrysanthemum leucantheum)
Perennial pepperweed (Lepidium latifolium)
Plumeless thistle (Carduus acanthoides)
Poison hemlock (Conium maculatum)
Purple loosestrife (Lythrum salicaria)
Russian knapweed (Acroptilon repens)
Russian olive (Elaeagnus angustifolia)
Salt cedar (Tamarix parviflora, Tamarix ramosissima)
Scentless chamomile (Tripleurospermum perforatum)
Scotch thistle (Onopordum acanthium)
Spotted knapweed (Centaurea maculosa)
Sulfur cinquefoil (Potentilla recta)
Yellow starthistle (Centaurea solstitalis)
Yellow toadflax (Linaria vulgaris)