Loading...
HomeMy WebLinkAboutFORT COLLINS NISSAN-KIA - PDP210017 - SUBMITTAL DOCUMENTS - ROUND 3 - WETLANDS DOCUMENTS 937 Mallard Drive, Ft. Collins, CO 80521 • (970) 224-0851 • www.bluemountainenvironmental.com April 13, 2022 Cathy Mathis, APA TB Group 444 Mountain Avenue Berthoud, CO 80513 RE: Fort Collins Nissan-Kia Revised Wetland Restoration Plan Ms. Mathis: This restoration plan is intended to be used for revegetation of two areas at Fort Collins Nissan- Kia: 1) wetlands within Detention Ponds and 2) Bioretention Areas. The approximate locations of these areas are illustrated on the Fort Collins Nissan-Kia Overall Grading Plan dated 10/6/2021 (here incorporated by reference). Areas to be restored occur principally on the southwestern portion of the proposed development. Our recommended approach for these two areas includes soil treatment, planting native vegetation, erosion control, irrigation, noxious weed management, and maintenance. Recommended restoration activities, as well as success criteria, are outlined on the following pages. This plan was prepared by Craig Severn, Amy Randell and Matt Tobler. Feel free to contact me with questions. Sincerely, Matt Tobler Natural Resource Specialist, Certified Ecologist Blue Mountain Environmental Consulting, LLC Ft. Collins Nissan – Kia Wetland Restoration Plan Wetland Restoration Plan This wetland restoration plan outlines treatments for the bottom and lower side slopes of the proposed detention ponds and bioretention areas (as identified on the Site Plan dated 10/6/2021). Note: This wetland restoration plan excludes areas immediately adjacent to bioretention swales as this area is include in the Upland Revegetation and Restoration Plan. The actual timing of project implementation is unknown, so only general temporal guidelines are provided. This plan includes guidelines for soil treatment, erosion control, planting wetland vegetation and site maintenance. This restoration plan assumes that water sufficient to support hydrophilic plants will be present, but future water availability is unknown. Table 1 below outlines restoration activities for each year. Table 1. Summary of restoration activities for Detention Pond and Bioretention Areas at Fort Collins Nissan-Kia. Year Reference Section Detention Pond Bioretention Area 1 early Soil Treatment Grade and stockpile approximately 55 to 60 cubic yards of wetland topsoil from the existing unnamed wetland (west of Venus Avenue). N/A 1 early Plant Topsoil Piles if Necessary Seed with sterile triticale or native seed mix depending on storage period. N/A 1 spring- summer Irrigation Irrigate topsoil piles if necessary to promote seed germination and plant growth. N/A 1 summer Grading/Topsoil Addition Establish a gentle gradient profile through bottom of pond area. Add 6 inches of wetland topsoil to graded bottom. Establish a profile through bottom of pond area. Add 6 inches of course textured soil to graded bottom and allow to settle. 1 late fall Plant Native Seed Mix(s) Drill or broadcast wetland seed mix into firm seed bed on pond bottom in late fall to early spring. Seed pond side slopes with upland native seed mix. Drill or broadcast sandy soil seed mix into firm seed bed in late fall to early spring. 1 After seeding Mulch Application All seeded areas will be mulched within 24 hours of seeding. Install Rolled Erosion Control Products (RECP) on slopes 3:1 or steeper. All seeded areas will be mulched within 24 hours of seeding. Install Rolled Erosion Control Products (RECP) on slopes 3:1 or steeper. 1 Wetland Plugs Order 10 cubic inch wetland plugs N/A Ft. Collins Nissan – Kia Wetland Restoration Plan late for spring planting. 2 spring Wetland plugs Plant wetland plugs to deep, mid, and shallow planting zone areas. N/A 2-4 spring-fall Monitoring and Maintenance Monitor seeded areas for weeds, irrigation needs, erosion, and bare areas. Implement need maintenance. Monitor seeded areas for weeds, irrigation needs, erosion, and bare areas. Implement need maintenance. 2-4 spring- summer Irrigation Irrigate if necessary to promote plug growth and seed germination and plant growth. Irrigate if necessary to promote seed germination and plant growth. 2 summer Noxious and Annual Weed Control If annual weeds are present, mow monthly with mowing heights no less than 4 to 6 inches. Manage noxious weeds. If annual weeds are present, mow monthly with mowing heights no less than 4 to 6 inches. Manage noxious weeds. 3-5 summer Noxious and Annual Weed Control If annual weeds are present, mow monthly with mowing heights no less than 10 inches. Manage noxious weeds. If annual weeds are present, mow monthly with mowing heights no less than 10 inches. Manage noxious weeds. 5 Determine Success Criteria Determine if success criteria for vegetative cover has been met. If success criteria have not been met, maintain growth for additional year. Determine if success criteria for vegetative cover has been met. If success criteria have not been met, maintain growth for additional year. Year 1 Early – Soil Treatment Detention Ponds Retain wetland topsoil displaced by grading operations from the unnamed wetland west of Venus Avenue and stockpile topsoil for distribution on the bottom of the detention ponds. Stockpile topsoil away from all drainage system components including swales and storm-sewer inlets. Where practical, choose stockpile locations that that will remain undisturbed for the longest period of time as the phases of construction progress. Place sediment control structures around the perimeter of the topsoil stockpile. This may include sediment control logs, rock socks, silt fence, straw bales or sand bags. Soil stockpiles shall not exceed 10 feet in height to preserve soil microbes that will aid in plant establishment (Urban Drainage and Flood Control District, 2016). Stockpiles shall be kept loose, not compacted, and watered as needed to prevent dust migration. Additional stockpile management practices are provided in the Fort Collins Stormwater Criteria Manual dated September 2018. Avoid piling anything, including subsoil, construction debris, etc., on the topsoil stockpile. Avoid handling topsoil when it is wet. Store upland and wetland top soils in separate piles. Stockpiles should be monitored for signs of erosion displacement and sediment accumulation and, if conditions warrant it, stockpiles shall be structurally covered if stored less than 30 days. Ft. Collins Nissan – Kia Wetland Restoration Plan Year 1 Early – Plant Topsoil Piles if Necessary Detention Ponds If topsoil is not going to be redistributed within 30 days within one growing season, plant a cover crop on the topsoil stockpile. We recommend QuickGuard Sterile Triticale to minimize colonization of non-native species. Broadcast QuickGuard Sterile Triticale at a rate of 40 pounds pure live seed (PLS) per acre followed by raking to incorporate seed into soil to a depth of ½ to ¾ inch. Seeding should be conducted after May 15 or after the last frost. Cover with weed-free straw mulch or hydro mulch. Seed in anticipation of precipitation or during winter when soils are not frozen. If soil is to be stored for more than one growing season, seed with a native prairie seed mix presented in Table 2 of the Upland Restoration Plan. The seed mix may be purchased from Pawnee Buttes Seed Company, Arkansas Valley Seed, or Western Native Seed. Year 1 Spring, Summer – Irrigation Detention Ponds If dry conditions persist after seeding the wetland topsoil stockpile, sprinkler irrigation may be necessary for successful seed germination. If dry conditions exist during the growing season, irrigation may be necessary for adequate plant establishment. Year 1 Summer – Grading/Topsoil Additions Detention Ponds In the lower portions of the detention basin restoration areas where wetland seed and plugs are to be planted, a gentle gradient profile across the basin will be established to provide for deep, mid, and shallow planting zones. The deep zone will represent 0.01 acres, mid zone 0.03 acres, and the shallow zone 0.03 acres in size. There should be approximately 1.5 feet elevation difference between the deep and shallow zones. When grading and contouring operations are complete, distribute approximately six inches of wetland topsoil to the bottom of detention ponds and allow to settle. Excess topsoil should extend evenly up the sides of the contoured bottom. Bioretention Areas Following application of coarse textured soil to the bottom of the bioretention areas, allow soil to settle (ideally with rainfall) for 7 days prior to seeding (Urban Drainage and Flood Control District, 2016; Shaw, 2018). At the time of seeding, a human footprint should compact the soil ¼ to ½ inch. Soil compaction with a cultipacker is not recommended on clay/loam soils because this treatment will result in soils that are too firm (Urban Drainage and Flood Control District, 2016). Year 1 Late Fall – Plant Seed Mixes Detention Ponds Restoration activities within detention ponds shall result in establishment of at least 0.07 acres of wetland to satisfy City of Ft. Collins requirements. Once the soil is settled, seed prairie wetland mix (as described in Table 2) from Pawnee Buttes Seed Inc. Seed should be planted with a native-grass-seed no-till drill at 10 pounds PLS per acre to the bottom on the detention ponds. Alternatively, broadcast seed with a Chapin® Professional Bag Seeder at double the rate (20 pounds PLS per acre) and rake into the soil. In either case, seed depth should be about ⅛ to ¼ Ft. Collins Nissan – Kia Wetland Restoration Plan inch into the soil in row 7 to 12 inches apart. The site should be seeded in late fall (after October 15) to allow seeds to naturally stratify over winter. Seeding is not recommended between June 1 and October 15. Provide adequate temporary irrigation for establishment of seeded areas as discussed in the section Maintenance of Seeded Area. Seed in anticipation of moisture or during the winter when soils are not frozen. Apply upland native seed mix (see Table 2 Upland Restoration Report) on adjacent upland side slopes per Upland Ecological Restoration Guidelines after wetland species are seeded on the bottom of the detention pond. Final drilling pass must occur on the contour, to create subtle ridges perpendicular to the flow of energy. If seed is broadcast on side slopes, a bulldozer may be used to compress seed into the soil. This step is not necessary if uplands are seeded with a no-till drill. This will encourage plant establishment on side slopes and provide extra erosion control. Native grass seed mix will need to be applied prior to placing Rolled Erosion Control Products on slopes 3:1 or steeper. All seeded areas on the upland sideslops shall be mulched within 24 hours of seeding, and the mulch shall either be adequately crimped and or tackified. Table 2. Pawnee Buttes Seed Company Prairie Wetland Mix for planting in the Detention Pond basins. Recommended seeding rate is 10 pounds per acre. Common Name Scientific Name Growing Zone Canada wildrye Elymus canadensis Shallow Switchgrass Panicum virgatum Shallow Prairie cordgrass Spartina pectinate Shallow Baltic rush Juncus balticus Shallow Nebraska sedge Carex nebrascensis Mid Creeping spike rush Eleocharis palustris Mid Three square bulrush Schoenoplectus pungens Mid Wooly sedge Carex pellita Mid Alkali bulrush Bolboschoenus maritimus Deep Soft stem rush Schoenoplectus tabernaemontani Deep Hardstem bulrush Schoenoplectus acutes Deep Bioretention Areas Once the soil is settled, seed a sandy soil native seed mix (as described in Table 3). Confirm the size of the area to be seeded. Seed should be planted with a no-till grain drill at 10 pounds PLS per acre on the bottom of the bioretention areas. Alternatively, broadcast seed with a Chapin Professional Bag Seeder at double the rate (20 pounds PLS per acre) and rake into the soil. In either case, seed depth should be about 1/8 to 1/2 inch. The site should be seeded in late fall (after October 15) to allow seeds to naturally stratify over winter. Seeding is not recommended between June 1 and October 15. Table 3. Sandy soil seed mix for bioretention areas. Common Name Scientific Name PLS/lb. PLS lbs/ac PLS/SF Ft. Collins Nissan – Kia Wetland Restoration Plan Switchgrass Panicum virgatum 389,000 0.80 7.1 Indiangrass Sorghastrum nutans 175,000 1.10 4.4 Sideoats grama Bouteloua curtipendula 190,000 1.50 6.5 Sand dropseed Sprobolus cryptandrus 5,200,000 0.06 7.2 Prairie sandreed Calamovilfa longifolia 273,000 1.16 7.3 Big bluestem Andropogon gerardii 130,000 0.90 2.7 Little bluestem Schizachyrium scoparium 260,000 0.90 2.7 Sand bluestem Andropogon hallii 113,000 0.80 2.1 Western wheatgrass Pascopyrum smithii 110,000 0.70 1.8 Indian ricegrass Achnatherum hymenoides 141,000 2.10 6.8 Weeping Alkaligrass Puccinellia distans 1,669,000 1.8 7.0 Inalnd Saltgrass Distchlis stricta 600,000 0.42 5.0 Alkali Sacaton Sporobolus airoides 1,750,000 0.10 4.2 Total 10.23 64.8 Year 1 – Mulch Application Detention Ponds and Bioretention Areas We assume that site activities will include all appropriate erosion control methods as determined by the project engineer to control erosion within drainage ditches, culvert outlets and on side slopes within 24 hours of seeding. Apply weed-free straw mulch to seeded areas at a rate of 2 tons per acre with 50 percent of the straw by weight should be 10 inches or more in length. Spread straw uniformly over seeded areas and crimp into the soil. Avoid spreading mulch when wind is in excess of 10 miles per hour. Hydro mulch application is also suitable. We recommend Rolled Erosion Control Products (RECP) on slopes 3:1 or steeper. It is best to avoid thick straw or excelsior blankets because they can impede grass establishment. It is recommended to use only biodegradable RECPs, such as coconut straw composite blankets or jute netting, because plastic netting may trap snakes, deer and other wildlife that may utilize the area. RECPs must be installed correctly to be effective such as preparing the soil, seeding before it is placed and placing in accordance with the manufacturer’s recommendations (Urban Drainage and Flood Control District, 2016). Year 1 Late – Order Wetland Plugs Detention Ponds Following the seed application, plant wetland plugs. Ten (10) cubic inch cone plugs should be pre-ordered from Aquatic and Wetland Nursery, LLC in Fort Lupton, CO to insure availability at time of spring planting. Refer to Table 4 for specific species and quantities. Table 4 Wetland species list and quantities for 10 cubic inch cone plugs to be planted in deep, mid, and shallow zones located in the detention basin restoration areas. Common Name Scientific Name Planting Zone Amount Baltic rush Juncus balticus Shallow 145 Ft. Collins Nissan – Kia Wetland Restoration Plan Inland saltgrass Distichlis spicata Shallow 145 Nebraska sedge Carex nebrascensis Mid 194 Creeping spike rush Eleocharis palustris Mid 194 Threesquare Schoenoplectus pungens Mid 194 Hardstem bulrush Schoenoplectus acutus Deep 194 Total 1,066 Year 2 Spring – Plant Wetland Plugs Detention Ponds Plant plugs in spring after May 15 or after the last frost when soil temperature is above 65° F. Deep, mid, and shallow planting zone areas representing 0.01, 0.03, and 0.03 acres respectively, will be established and then planted to the corresponding species as shown in Table 4. Use a shovel or hand-held digging tool to open a hole slightly deeper than plug, insert plug and firm soil around plug. Evenly space plugs throughout the wetland in the appropriate planting zone on 18 inch centers. Be mindful of trampling if wetland seed mix was dispersed in the fall. If seeds were not planted in the fall, broadcast seed after plugs are planted to reduce trampling. Year 2-4 – Monitoring and Maintenance Detention Ponds and Bioretention Areas Seeded and plugged areas shall be monitored several times a year for three or more years to ensure that success criteria will be met. Monitoring may require that adaptive management be employed as site conditions dictate. Conditions affecting the timing and frequency for monitoring include temperature, precipitation, plant phenology, timing of site activities, etc. Monitoring will include the following: presence and abundance of weeds; irrigation needs; erosion issues; and bare areas needing reseeding. Site conditions shall be communicated to the project team with appropriate action(s) taken as necessary. Weed issues should be addressed, irrigation shall be provided as seasonal trends dictate, additional erosion control measures may also be necessary, and bare areas should be reseeded. Year 2-4 spring-summer – Irrigation Detention Ponds Water management is critical during wetland plant establishment, remaining crucial throughout the life of a wetland (Hoag & Tilley, 2007). If seeds are planted in fall, then irrigation will not be necessary until spring of next year. If dry conditions are present in the spring after wetland plug planting, irrigation may be necessary for successful plug establishment and wetland seed mix germination. During early plant establishment, seedling roots are near the surface and benefit from frequent, short irrigation periods (Urban Drainage and Flood Control District, 2016). For native seed to germinate, the top 1-2 inches of soil should be moist, but not saturated, (Urban Drainage and Flood Control District, 2016). Complete inundation of most plant species during germination can be lethal (Hoag & Tilley, 2007). Once plants are established, decrease irrigation Ft. Collins Nissan – Kia Wetland Restoration Plan frequency to 3-4 days per week (too frequent irrigation can encourage shallow rooting; Urban Drainage and Flood Control District, 2016) and increase duration, allowing moisture to reach a depth of up to 6 inches in the soil. Once seeded plants are established, irrigation should be decreased to 2 days per week from late summer until the fall when irrigation should cease (Urban Drainage and Flood Control District, 2016). It is recommended to irrigate early in the morning (before sunrise) or in the evening (before sunset) to conserve water during the growing season and to prevent fungal diseases. Refer to Table 5 for a sample irrigation schedule. In the event that sufficient precipitation during the period of plug establishment and seed germination occurs naturally, then the irrigation schedule can be suspended until drier condition exist and irrigation is needed. Table 5. Recommended irrigation schedule for Detention Ponds. Time of Year Frequency Morning Water Evening Water Soil Moisture Depth (inches) Mid-April to mid-May 1-2x/day until avg. temp is 80º F 1x 1x 2 Early June to July Every other day, if avg. temp is 90º F then 1x/day 1x 0 6 July to mid-August 1x/week 1x 0 6 Mid-August to mid- September 1x every other week 1x 0 6 Mid-September to April Withhold watering to allow plants to harden for winter 0 0 0 Bioretention Areas If dry conditions persist in the spring after seeding, sprinkler irrigation may be necessary for successful seed germination. If dry conditions exist during the growing season, irrigation may be necessary for adequate plant establishment and growth. Assuming that the project is seeded in fall or early spring, irrigation shall be initiated in the first year after planting after springtime moisture is no longer available. Seeded areas shall be irrigated in the morning once per day until seed have germinated and grown past the three leaf stage. Irrigation shall be sufficient to moisten the top 1-2 inches of soil without generating runoff. Irrigation shall continue throughout the first summer and fall after planting at a rate of two to four times per week depending on site conditions. Irrigation will likely be necessary one to three times per week in the summers of year three and four. Year 2 Summer– Noxious and Annual Weed Control Ft. Collins Nissan – Kia Wetland Restoration Plan Detention Ponds and Bioretention Areas If annual weeds are present, mow monthly with mowing heights no less than 4 to 6 inches. Use of a narrow blade spade shovel for removing large tap roots, hand pulling, or spot herbicide application via a wick or spray applicator can be used to control other undesirable species as necessary. Digging or hand pulling undesirable plants when soil is moist will be the most effective means of control provided sufficient labor is available. Apply spot-control herbicide with a hand-held, backpack sprayer or wick applicator. Spot control of Canada thistle is especially important during early plant establishment as this noxious weed species can be aggressive during early plant establishment and is difficult to control once it has become established. Areas where soils are commonly saturated or moist are conducive to Canada thistle invasion. Herbicide application is to be conducted by a licensed commercial applicator. It is important note that many herbicides are toxic in aquatic ecosystems and may cause significant risks to human health. Herbicides can enter water-bodies either directly through spray or spray drift, or they can move into water-bodies via surface water run-off or leaching and sub-surface draining. Herbicides used in and around wetland areas should be labeled for use in wetland areas. Several State-listed noxious weed species are present on the property and should be actively managed to prevent their establishment in restored areas including leafy spurge (Euphorbia esula), musk thistle (Carduus nutans), Dalmatian toadflax (Linaria dalmatica), field bindweed (Convolvulus arvensis), and mullein (Verbascum thapsus). Other undesirable species include cheatgrass (Bromus tectorum), kochia (Bassia scoparia), Russian thistle (Salsola iberica), yellow salsify (Tragopogon dubius), prickly lettuce (Lactuca serriola), yellow sweet clover (Melilotus officinalis), pennycress (Thlaspi arvense), and flixweed (Descurainia sophia). Noxious weed management guidelines are provided in Appendix A. Years 3-5 – Noxious and Annual Weed Control Detention Ponds and Bioretention Areas If annual weeds are still present, mow monthly with mowing heights no less than 10 inches. Use methods described in Year 2 above to control noxious and other weeds. Year 5-6 – Measure Success Criteria Detention Ponds and Bioretention Areas Success criteria for security release is detailed in the Development Agreement (DA), which is specific to each project. The standard success criteria is 70% average vegetative cover with less than 10% cover of noxious weeds and no bare ground areas greater than 1 square foot. Cover requirements are expected to be achieved within three to five years after planting the native seed mix under normal growing conditions of temperature and natural moisture. Monitoring and Maintenance Seeded areas shall be monitored several times a year for three or more years to ensure that success criteria are met. Monitoring and adaptive management shall be employed as site Ft. Collins Nissan – Kia Wetland Restoration Plan conditions dictate. Conditions affecting the timing and frequency of site visits include temperature, precipitation, plant phenology, timing of site activities, etc. Site conditions shall be communicated to the project team with appropriate redirection taken as necessary. Bare areas should be reseeded, additional erosion control measures may also be necessary and irrigation shall be provided as seasonal trends dictate. Monitoring results shall be communicated to the project manager who will inform the City of Ft. Collins regarding on the ground conditions and adaptive management strategies. Ft. Collins Nissan – Kia Wetland Restoration Plan Appendix A: Noxious Weed Management Ft. Collins Nissan – Kia Wetland Restoration Plan Canada Thistle Cirsium arvense is an exotic perennial forb that can spread by seed, but is more of a problem due to its ability to spread rapidly from vigorous rhizomes that can extend 15 feet from the parent plant and 6-15 feet deep (Beck 2013). It is an erect plant that can grow up to 5 feet tall. Flowers are small, ranging from white to deep purple. Leaves are usually deeply incised with spiny margins. Infestations often begin on disturbed sites such as ditches, overgrazed pastures, or waste areas (Beck 2013). Canada thistle is a problem weed in riparian areas, but is also found in upland sites. Seeds are able to germinate within 8 to 10 days of pollination. Canada thistle begins growth as a rosette from mid-April to May. It flowers in June, but produces seed sparingly, relying on its extensive root system for spread. Seeds can remain viable in the soil for up to 22 years (Beck 2013). The key to managing this thistle is to stress the plant, forcing it to use its stored root nutrients (Beck 2013). Biological control: The weevil Ceutorhyncus litura is currently being used in Colorado as a biocontrol agent, and another biocontrol insect, Urophora cardui, has also been used (Beck 2013). Biological controls alone are not effective and must be used in conjunction with other strategies such as cultural and chemical practices. Mechanical control: Mowing decreases plant vigor and seed set. However, mowing may not be viable given the plant's dispersal in riparian areas. Hand pulling is effective to control small populations, but is not practical for large populations due to the deep and extensive network of underground rhizomes. When seed heads are encountered they should be clipped well below the apex, bagged, and disposed of in a dumpster. Mowing is effective only if conducted at one- month intervals over several growing seasons, or used with chemical practices (Beck 2013). Chemical control: Herbicides should be used only per label directions, and caution should be taken since the weed occurs near water where many chemicals can harm aquatic life. Herbicides should be applied by licensed commercial applicators. Research from Colorado State University shows that picloram, aminopyralid, clopyralid, aminocyclopyrachlor + chlorsulfuron, dicamba, and chlorsulfuron are effective in pastures, natural areas, and non-crop settings (Beck 2013). Re- treatment for 1-3 years is common. Cultural control: Increase competition with native perennial grasses and alfalfa. Keep moisture at optimum levels to favor grass or alfalfa growth (Beck 2013). Integrated management: Control efforts should target plants in high-quality areas first. Management strategies should be adjusted to reflect weather conditions. For example, drought stress reduces the effectiveness of most herbicides but increases the effectiveness of mechanical controls. It takes at least two years of control to determine if a method is effective. Ft. Collins Nissan – Kia Wetland Restoration Plan Cheatgrass Bromus tectorum is an exotic winter annual grass that is one of the most widely distributed weeds in the western U.S. Cheatgrass has been shown to significantly alter the fire regime of ecosystems (D’Antonio and Vitousek 1992). It is an erect-stemmed, annual grass that grows 8-25 inches tall. The flowering part of the grass is generally nodding with slender, straight awns. It germinates in the fall or early spring and sets seed from May to June. Cheatgrass flourishes in moderately to highly disturbed upland sites such as roadways, overgrazed areas, and waste sites. It initiates early spring growth and aggressively uses deep soil resources. Seeds are dispersed by animals and people who transport seeds in fur, socks, boots, muddy tires, etc. Because seeds remain viable for up to five years, control measures that reduce seed are most effective. Biological control: Intense grazing can reduce seed production by 90%. Cattle find cheatgrass highly palatable in early spring before seed set occurs. Once seed set occurs, plants drop in palatability and quality. Where infestations are large and dense, prescribed spring grazing repeated for 3 to 5 years by livestock can be effective, and indeed may be the only option in areas where it is difficult or impractical to implement other prescriptions (Shoderbek 2015). Mechanical control: Mechanical control efforts are not recommended unless they are followed by an aggressive revegetation and chemical control program. When mechanical control is used, it should be done in early spring before seed heads are fully developed (early to mid-May) and repeated for at least 5 years. For small infestations, hand-pull weeds. For larger infestations, mow before seed set, repeating every 2 to 3 weeks until flowering is complete (USFS 2014). Chemical control: Rejuvra is a pre-emergence herbicide that works to stop cheatgrass while it’s germinating by inhibiting normal root growth. If applying after germination, mix with a post- emergence herbicide such as Plateau or Rimsulfuron (mid-August to mid-October), or Roundup Pro Concentrate or Rimsulfuron + NIS (late-October through April) as per label instructions. It is not recommended to allow cattle to graze immediately after application (Learn about Rejuvra [date unknown]; D. Sebastian, e-mail message, October 29, 2021). Cultural control: Due to the broad distribution of this plant, tilling and seeding operations are not practical. In areas where revegetation efforts have not produced a healthy stand of perennial grass cover, inter-seeding with native perennial grasses, following cheatgrass spot-control, can be effective. Prescribed burns in areas with mixed shrub and grasses during late spring to early summer have been used with some success, but burning is most effective when used in combination with chemical methods and rigorous reseeding of native perennials (USFS 2014). Integrated management: Lasting control of cheatgrass requires a combination of chemical and mechanical control, reseeding with native perennials, and proper livestock management where land is grazed. This method keeps plants under stress, reducing their ability to spread. Ft. Collins Nissan – Kia Wetland Restoration Plan Common Mullein Common mullein (Verbascum thapsus) is a biennial forb that can easily be identified by its yellow flowers grouped in a "corn cob" shaped flowering raceme. The leaves are light green and densely wooly. Mature plants have a single, erect stem that can grow 6 to 8 feet in height. Seeds germinate in the early spring, forming a rosette that continues to grow into late autumn and over winter. A tall stem topped with the flowering raceme is produced the following spring. Common mullein can be hard to control due its prolific seed production. The seeds can germinate after lying dormant for several decades. Mullein is easily outcompeted in areas with a densely vegetated ground cover but readily grows in disturbed sites, such as areas that have high human activity or an abundance of bare ground. Mullein prefers dry coarse-textured soils, and is common throughout Colorado in pastures, meadows, waste areas, and along river bottoms. Biological control: The European curculionid (Gymnetron tetrum) feeds on the seeds and has some success in reducing seed production, though there is little recent research on the subject (Gross and Werner 1978). Mechanical control: Mullein plants have shallow tap roots and are easily hand-pulled. They should be pulled as soon as they are large enough to grasp but before they produce seeds. Mullein stems can be cut or mowed to prevent flower and seed production, but stems must be cut below the root crown or rosettes will re-bolt (CNAP 2000). We recommend planting native perennials after mechanical control because mullein favors bare soil. Chemical control: Herbicide application is most effective during the rosette stage. Due to the wooly nature of the leaves, herbicides should be mixed with a surfactant to facilitate uptake. Effective herbicides include metsulfuron at 0.6 oz. ai/acre, tebuthiuron at 4-6 lb. ai/acre (CNAP 2000). Cultural control: Minimize disturbance and seed dispersal, eliminate seed production and maintain healthy native communities. Mullein is often an early invader of burned areas. Integrated management: Management efforts must include the elimination of seed production and the depletion of the seed bank. Combine herbicide or mechanical removal of rosettes with removal of seed heads from any plants that have bolted as well as reseeding bare areas with native perennials. Ft. Collins Nissan – Kia Wetland Restoration Plan Dalmatian Toadflax Linaria dalmatica is an exotic perennial forb that easily invades natural ecosystems, thereby displacing native vegetation. It has yellow flowers with an orange lip. The leaves are heart-shaped and clasp the stem. Dalmatian toadflax germinates from mid-March to May, and flowers from May to June and given sufficient moisture, can continue flowering into the fall. By initiating early top growth from underground roots (which can reach a depth of 6 feet or more), it effectively competes with native plants for light, soil moisture, and other nutrients. It spreads efficiently from seed as well as from root buds that can travel underground up to 10 feet. In wet years, these plants reproduce abundantly from seed. However, since seedling root development is slow, this represents a life stage vulnerable to control. All toadflax species are difficult to control, so it is recommended to integrate as many management strategies as possible for successful management (Beck 2014). Biological control: Several biocontrol agents have been used to control toadflax but the success of these agents has not been sufficient. A defoliating moth (Calophasia lunula), an ovary-feeding beetle (Brachypterolus pulicarius), and two seed capsule-feeding weevils (Gymnaetron antirrhini and G. netum) have been used in the U.S. and Canada. These flower- and seed-feeding beetles should help decrease seed production. Mecinus janthinus, a stem-boring weevil, and a root-boring moth, Eteobalea intermediella, were also released in Canada and the U.S. to control all species of toadflax. These species help to control shoots and seed production as well as decrease root vigor, but research is lacking (Beck 2014). Mechanical control: Disturbance promotes the invasion of toadflax and it may be necessary for plant establishment. Mowing combined with spraying was not found effective in a study from Colorado (Beck 2014). Chemical control: Tordon 22K at 2 pints/acre sprayed at the time of flowering or in the fall has proven successful in Colorado. Spraying as well as planting native perennial grasses is more effective than spraying alone (Beck 2014). Cultural control: There is very little research supporting cultural controls being effective against this weed in Colorado. Integrated management: Successful management requires integrating as many control tactics as possible. Control can be obtained by pulling or killing the plants with herbicide before seed production begins. This process must be repeated every year for at least 10 years to completely remove a stand. Competitive perennial grasses and forbs should be planted to utilize water and nutrients that would otherwise be readily available to toadflax. Ft. Collins Nissan – Kia Wetland Restoration Plan Field Bindweed Field bindweed (Convolvulus arvensis) is a perennial forb identifiable by its leaves, which are the shape of arrowheads, and its white to pink funnel-shaped flowers. It favors areas with drought- stress and poor irrigation coverage. Flowers appear from June to September, and seeds mature within two weeks after pollination during hot summer days. Germination can occur in the fall or spring. Field bindweed can be a serious threat to native plant communities because of its high capacity for regeneration. Its seeds can easily live for 50 years in the soil, and its tremendous root system and rhizomes have the potential to produce large numbers of new shoots. It is highly competitive in most areas. However, field bindweed cannot tolerate shade, and it is unlikely that it would persist in later stages of community succession (CNAP 2000). Biological control: A small mite, Aceria malherbae, has been found to be somewhat effective in controlling bindweed in conjunction with other management practices. The mites infest the new growth of the plant by forming a leaf gall. This reduces flowering and stunts stem growth. The mites will overwinter on the root buds and emerge again in the spring. The mites should be released in a thick infestation that will not be sprayed with chemicals or receive heavy watering (Field Bindweed Biocontrol [date unknown]). Mechanical control: Mowing or hoeing may be an effective tool to manage bindweed and it may help spread Aceria malherbae to new locations, though mowing may be hard because of the plant’s low growth habit (Field Bindweed Biocontrol [date unknown]). Remove as many deep horizontal rhizomes as possible. Apply repeated mechanical treatments when plants are young. Chemical control: Pre-emergence herbicides are not recommended because of bindweed’s extensive root system; systemic post-emergence products must be used. Foliar application of glyphosate at 1.5 lb. ai/acre or picloram at 0.25-0.5 lb. ai/acre or 2-4 D at 1lb. ai/acre can be effective. Repeated applications are recommended. Quinclorac is highly effective at controlling bindweed. The chemical can be found in some commercial products. These herbicides are labeled to only be used in lawns and cannot be legally or safely used in landscape beds or vegetable gardens (Bindweed Control in Lawns [date unknown]). Cultural control: Maintain a healthy cover of native perennial plants to discourage field bindweed establishment. Integrated management: Field bindweed requires active management once it is established because of its potential to regenerate rapidly. Successful treatment of bindweed can result in significant damage to desirable vegetation. Ft. Collins Nissan – Kia Wetland Restoration Plan Leafy Spurge Euphorbia esula is an aggressive, long-lived perennial weed that displaces native plants in many habitats (Biesboer 1998). Leafy spurge produces a large number of seeds and has extensive lateral root systems with which it can reproduce vegetatively. These two reproductive strategies allow this plant to rapidly form monocultures. Large nutrient reserves in root systems allow this plant to re-establish in treated areas; it also produces an allelopathic compound that inhibits growth of other plants (Butterfield et al. 1996). Spurge can grow in a wide variety of habitats, but is best adapted to semi-arid settings. It typically occurs in untilled rangelands and is most abundant on coarse textured soils. Leafy spurge emerges early in the spring (mid April to late May), flowering ends in June to mid July. Photo from Whitson et al. (1996). Biological control: The Division of Plant Industry’s Biological Pest Control Section has released eight species to control leafy spurge. The most effective biological control agents are six species of root and foliage feeding beetles in the genus Aphthona, and a stem and root boring beetle Obera erythrocephala (Lajeunesee et al. 1999). Mechanical control: Tillage is not practical in many areas, mowing can increase plant density and may not be effective when combined with herbicide. Hand pulling is ineffective due to extensive root systems. Burning is moderately effective when it is combined with herbicide application after five weeks. Chemical control: Herbicide applications can be successful but successive treatments are required due to the extensive root systems of this plant. A combination of picloram and 2,4-D (1- 1.5 pints of picloram with 1-1.5 quarts of 2,4-D) has shown to provide best control when applied in the spring when flowers emerge (Beck 1996). Picloram at 1 quart/acre for two to three consecutive years is also effective, but costly. An annual combination of dicamba plus 2,4-D (4- 8 ounces with 0.5 to 1 quart per acre) also provided good control (Beck 1996). Glycoghosate is most effective when applied sequentially at 1 quart/acre at one month intervals, coupled with fall grass seeding (Beck 1996). Cultural control: Long-term control requires the establishment of competing vegetation. Seed mixtures should contain plants with early, mid and late growth as well as shallow, intermediate and deep roots. Integrated management: Leafy spurge is extremely difficult to control by chemical means and almost impossible to control with cultural or mechanical means. Therefore a management scheme that combines control methods over four to five years is recommended (Beck 1996). Ft. Collins Nissan – Kia Wetland Restoration Plan Musk Thistle Carduus nutans is an exotic winter annual or biennial that flowers from July to late September. It has bright purple flowers (3 inches wide) that are nodding (State Designated Noxious Weeds). The leaves are dark green with light-colored, spiny and deeply lobed margins (State Designated Noxious Weeds). It generally invades areas that are overgrazed or are experiencing poor perennial grass cover; establishment is favored by high levels of moisture and light. The average plant produces more than 10,000 seeds that are readily dispersed by the wind, thereby infesting large areas within two growing seasons, and are viable for up to 10 years in the soil (State Designated Noxious Weeds). Control can be obtained by reducing seed set and depleting the seed bank. Biological control: The musk thistle rosette weevil, or crown weevil, (Trichosirocalus horridus), is the only biological control agent released by the Colorado Department of Agriculture Insectary. The weevil occurs in the developing root tissue of the plant, stunting the growth and number of stems C. nutans can produce. The plant stem and foliage will start to yellow as the weevil damage accumulates (Musk Thistle Biocontrol [date unknown]). Mechanical control: Mowing with a weed whip or scythe can be a useful mechanical control when plants are just beginning to flower to reduce seed set. Repeat treatments are necessary because individual plants of C. nutans do not bloom at the same time. Grubbing or digging, being sure to get the root, can be effective as well. Mechanical control should be combined with biological methods. Chemical control: Effective chemical control has been achieved in the past using picloram (Tordon 22K), clopyralid (Transline, Stinger), clopyralid plus 2, 4-D (Curtail), chlorsulfuron (telar), glyphosate (Roundup/Rodeo), dicamba (Banvel), and 2, 4-D. Applications should be made in late spring/early summer and again in the fall. Cultural control: We recommend inter-seeding disturbed sites to prevent the spread of this plant. If competitive vegetation is not established, re-invasion is likely. Integrated management: Prevent seed production. Most control methods have a detrimental effect on other plants and may cause a disturbance that favors other exotic species. Dense musk thistle stands along roadsides and in degraded areas can be treated by spot use of herbicides, and in high quality areas by persistent pulling or cutting. Up to 10 years of control may be needed to completely eliminate a stand. Ft. Collins Nissan – Kia Wetland Restoration Plan References Beck, G.B. 1997. Musk Thistle. Colorado State University Cooperative Extension. No. 3.102. Fort Collins, CO. Beck KG. 2013 Nov. Canada Thistle. Colorado State University Extension [Internet]. [cited 2021 Oct 21]. Available from: https://extension.colostate.edu/topic-areas/natural- resources/canada-thistle-3-108/ Beck KG. 2014 Dec. Biology and Management of the Toadflaxes. Colorado State University Extension [Internet]. [cited 2021 Oct 22]. Available from: https://extension.colostate.edu/topic-areas/natural-resources/biology-and-management-of- the-toadflaxes-3-114/ Bindweed Control in Lawns. [date unknown]. Colorado State University Extension [Internet]. [cited 2021 Oct 22]. Available from: https://planttalk.colostate.edu/topics/lawns/1552- bindweed-control-lawns/ Biesboer, D.D. 1998. Element stewardship abstract for Euphorbia esula. The Nature Conservency. Wildland Weeds Management and Research Program. Cheatgrass, downy brome Bromus tectorum L. [date unknown]. Invasive Plant Atlas of the United States [Internet]. [cited 2021 Oct 20]. Available from: https://www.invasiveplantatlas.org/subject.html?sub=5214 Colorado Natural Areas Program (CNAP). 2000. Creating an Integrated Weed Management Plan: A Handbook for Owners and Managers of Lands with Natural Values. Colorado Natural Areas Program, Colorado State Parks, Colorado Department of Natural Resources; and Division of Plant Industry, Colorado Department of Agriculture. Denver, Colorado. 349 pages. D'Antonio, C.M., P.M. Vitousek. 1992. Biological invasions by exotic grasses, the grass/fire cycle, and global change. Annual Review of Ecology and Systematics 23:63-87. Field Bindweed Biocontrol. [date unknown]. Colorado Department of Agriculture [Internet]. [cited 2021 Oct 22]. Available from: https://ag.colorado.gov/conservation/biocontrol/field-bindweed Gross, K.L. and P.A. Werner. 1978. The biology of Canadian weeds: Verbascum thapsus and V. blatteria. Can. J. Plant Science 58:401-413. Hoag J.C., Tilley D. 2007 Jun. How to Manipulate Water in a New, Restored, or Enhanced Wetland to Encourage Wetland Establishment. Riparian Wetland Project Information. 22: 1- 5. Lajeunesse, S.E., R.L. Sheley, R. Lym, and C. Duncan. 1999. Leafy spurge. In R.L. Sheley and Petroff, eds. Biology and Management of Noxious Rangeland Weeds. Oregon State University Press, Corvallis, OR. Learn about Rejuvra herbicide Stewardship. [date unknown]. Bayer United States Vegetation Management [Internet]. [cited 2021 Oct 22]. Available from: https://www.environmentalscience.bayer.us/vegetation-management/range-and- pasture/portfolios-and-solutions/rejuvra/stewardship#Application Ft. Collins Nissan – Kia Wetland Restoration Plan Musk Thistle Biocontrol. [date unknown]. Colorado Department of Agriculture [Internet]. [cited 2021 Oct 22]. Available from: https://ag.colorado.gov/conservation/biocontrol/musk- thistle Musk Thistle (Carduus nutans L.). Adams County Colorado State University Extension. [Internet] [cited 2021 Oct 22]. Available from: http://adams.colostate.edu/ag/muskthistle.htm Shaw D. 2018. What’s Working for Conservation Wetland Establishment. MN Board of Water and Soil Resources [Internet]. [cited 2021 Oct 18]. Available from: https://bwsr.state.mn.us/project-engineering-construction-and-establishment-wetland- establishment. Shoderbek D. 2015 Jul 15. How to beat the ‘cheat.’ Livestock & Range Colorado State University Extension [Internet]. [cited 2021 Oct 20]. Available from: https://rangemanagement.extension.colostate.edu/land-and-livestock/invasive- plants/how-to-beat-the-cheat/ United States Forest Service (USFS). 2014 Sep. Field Guide for Managing Cheatgrass in the Southwest. 1-12. Urban Drainage and Flood Control District. 2016 Jan. Urban Storm Drainage Criteria Manual. 2. [cited 2021 Oct 18]. Available from: https://udfcd.org/wp- content/uploads/uploads/vol2%20criteria%20manual/13_Revegetation.pdf.Whitson, T.D. (ed.), L.C. Burrill, S.A. Dewey, D.W. Cudney, B.E. Nelson, R.D. Lee, R. Parker. 1996. Weeds of the West. Western Society of Weed Science, in cooperation with the Western United States Land Grant Universities Cooperative Extension Services, Newark, CA.