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HomeMy WebLinkAboutCOUNTRY CLUB RESERVE - FDP180030 - - SUPPLEMENTAL INFORMATION Country Club Reserve Weed Management Plan November, 2020 PO Box 272150 Fort Collins, CO 80527 i Table of Contents 1.0 Introduction ................................................................................................................................ 1 2.0 Existing Conditions ...................................................................................................................... 1 3.0 Weed Management ...................................................................................................................... 3 3.1 Best Management Practices .................................................................................................... 3 3.2 Weed Treatment Options and Recommendations ..................................................................... 3 3.2.1 Canada Thistle (B List) .......................................................................................... 4 3.2.2 Field Bindweed (B List) .......................................................................................... 6 3.2.3 Leafy Spurge (B List) ............................................................................................. 7 3.2.4 Cheatgrass (C List) ................................................................................................ 9 3.2.5 Common Mullein (C List) ...................................................................................... 10 3.2.6 Musk Thistle (B List) ............................................................................................ 11 3.2.7 Russian Olive (B List)........................................................................................... 12 4.0 Weed Monitoring ....................................................................................................................... 13 5.0 Literature Cited and Data Sources .............................................................................................. 14 Country Club Reserve Weed Management Plan 1.0 INTRODUCTION The Weed Management Plan is part of the developer’s goal to control noxious weeds across the entirety of the Site. Effectively controlling noxious weeds will help preserve or enhance the ecological and aesthetic character and wildlife use of the Natural Habitat Buffer Zone (NHBZ) and to minimize or adequately mitigate the foreseeable impacts of development. The goal of the Weed Management Plan is to provide guidance on specific weed treatments. 2.0 EXISTING CONDITIONS A field evaluation of noxious and invasive weeds was implemented in November 2020. This survey revealed the presence of cheatgrass (Bromus tectorum – C List), field bindweed (Convolvulus arvensis), Canada thistle (Cirsium arvense – B List), leafy spurge (Euphorbia esula – B List), and Russian olive (Elaeagnus angustifolia – B List) within or in the nearby vicinity of the NHBZ and associated wetlands. Additionally, the original ECS (Walsh 2006) reported musk thistle (Carduus nutans– B List) and common mullein (Verbascum thapsus – C List) on Site. It is possible that leaf senescence prior to the November 2020 survey precluded the differentiation of musk thistle from Canada thistle, or that neither reported species have established in the NHBZ boundaries. Given the pervasive nature of noxious weeds, it is unlikely that these populations have been completely eradicated from the Site since 2006. Their potential presence indicates the NHBZ is at risk for infestation despite no observations in 2020, and as such, all noxious weed species have been considered in weed management planning efforts for the NHBZ. • List A species are not well established in Colorado, are potentially a large problem to this state, and require mandatory eradication by local governing agencies. Prescribed techniques for management of List A species are hand pulling, digging, or herbicide application. Mowing, grazing, and insect bio-control are not acceptable forms of management for these species. • List B species are common enough in parts of the state that eradication is not feasible, though the species are still recommended for eradication, suppression, or containment depending on distribution and densities around the state. Prevention of seed dispersal may be accomplished by mowing, hand pulling, tillage, grazing, or herbicide application. • List C species are widespread and well established. Control of List Band C species is recommended but not required by the state. However, local governing bodies, such as Larimer County or City of Fort Collins, may require management. Existing conditions in the northeastern NHBZ (November 2020) Existing conditions in the North-central NHBZ (November 2020) 3.0 WEED MANAGEMENT 3.1 Best Management Practices Noxious weeds are common in urban and developed areas, and construction-related ground disturbance creates ideal conditions for the spread of noxious weeds. Nevertheless, there are some general practices that can be followed to limit the spread and/or establishment of noxious weeds during construction activities. Pre-Construction Phase • Treat existing noxious weed populations that could be spread by construction activities, especially individual plants and small infestations. Aggressive treatment of existing weed populations greatly reduces the ability of the weeds to rebound in post-construction conditions. Seeding, Planting, and Post-construction Phases • Require equipment (especially dirt-moving equipment like bulldozers and excavators) to be washed and weed-free before entering the Site. • Use only certified weed-free straw and mulch for erosion control projects, including weed-free fiber roll barriers and/or sediment logs. • Obtain soil components, amendments, seed mixes, and mulches from weed-free sources. • Establish and maintain vigorous, desirable vegetation to discourage weeds. • Mulch any non-vegetated surfaces to minimize the amount of noxious weed seeds that will reach the soil surface and germinate. • Monitor all seeded areas for any weed infestations post-construction and to inform subsequent weed management activities. 3.2 Weed Treatment Options and Recommendations A Licensed Pesticide Commercial Applicator (LPCA) for Larimer County will be used to apply herbicide to control noxious weeds on this Site. Permits for LCPA may contain additional terms and conditions that go beyond the scope of this management plan. The LCPA will perform the application in accordance with applicable laws and regulations and permit stipulations. All herbicide applications must follow US Environmental Protection Agency label instructions, including taking proper precautions (proper storage, following spill clean-up procedures, and proper disposal of containers). Application of herbicides will be suspended when any of the following conditions exists: • Wind velocity exceeds 6 miles per hour (mph) during application of liquids or 15 mph during application of granular herbicides. • Snow or ice covers the foliage of noxious weeds. • Precipitation is occurring or is imminent. Vehicle-mounted sprayers (e.g., handgun, boom, and injector) will be used mainly in open areas that are readily accessible by vehicle. Hand application methods (e.g., backpack spraying, hose and wand spraying) that target individual plants will be used to treat small or scattered weed populations in rough terrain. Calibration checks of equipment will be conducted at the beginning of spraying and periodically to ensure that proper application rates are achieved. Specific treatment plans (as well as herbicide recommendations) for the noxious weeds present on Site are described below. All noxious weeds are expected to require multiple years of treatment to effectively control populations. 3.2.1 Canada Thistle (B List) Species Background Canada thistle is one of the most troublesome noxious weeds in the US and is the most dominant noxious weed on Site. Patches of Canada thistle are prominent throughout the north-central wetland and associated NHBZ, as well as sporadically throughout the Site. As such, long-term vigilance will be necessary to prevent re-colonization. Canada thistle is an aggressive non-native, deep-rooted, perennial plant (CDA 2008). The plant first emerges as a rosette, the first flush of which occurs from April to May. Flowering occurs in late spring and throughout the summer, often followed by a second flush in the fall. However, a flush is possible any time during the growing season if sufficient soil moisture is available. Canada thistle also reproduces by seed or vegetatively; seeds account for long distance dispersal while vegetative reproduction from its root system accounts for local spread. Seed set occurs in mid- to late- summer, with 1,000-1,500 seeds produced per plant that are dispersed by animals, vehicles, and/or wind. Seeds remain viable for up to 20-22 years. Canada thistle has an extensive system of creeping horizontal roots, otherwise known as rhizomes. Vertical roots grow six to 15 feet deep, and rhizomes extend 15 feet or more in any direction. Rhizomes as small as a ¼ inch long have enough stored energy to develop new plants and can survive for 100 days without nutrient replenishment from photosynthesis (CSU 2013). Control Approach Aspects of Canada thistle’s phenology can be exploited to a land manager’s benefit, with the goal being to stress the plant to the point that root stores of nutrients and energy are exhausted. The plants draw on root stores for the first spring flush, and the plants should be allowed to grow to the bud stage but then killed to prevent seed production. Additional treatment of top growth should be implemented midsummer as the plants recover from the initial spring treatment to further stress the plant and to prevent seed set. The most critical step is the fall treatment with a translocating herbicide, in which the herbicide is applied to top growth but is transported to the root system as the plant stores nutrients and energy in the roots in preparation for the spring. Seeding of native grasses will provide competition for resources while being generally unaffected by herbicide applications, and early establishment of native species that will be desired in the long-term future as well. Biological control agents exist for Canada thistle but are not recommended for the Country Club Reserve project due to timing restrictions and the use of herbicides. Pre-Construction • Herbicide treatment in the spring and summer to eliminate top growth, followed by a fall application of a translocating herbicide. • If possible, plan grading operations to avoid moving Canada thistle-infested soil/subsoil from one location to another on Site to avoid spread by root fragments. • Spot-treatment of individuals (either mechanically or chemically) during the construction phase to further stress plants and prevent seed set. Post-Construction • Establishment of healthy stands of desirable vegetation to out-compete Canada thistle. • Mulching exposed non-seeded areas to prevent germination of Canada thistle seed or vegetative re-growth. • Spot-treatment of individuals both mechanically or with herbicide during the construction phase to further stress plants and prevent seed set. Herbicide Recommendations Table 1 below contains the herbicide recommendations provided by the Colorado Department of Agriculture (CDA) (2008) for Canada thistle in range conditions. 3.2.2 Field Bindweed (B List) Species Background Field bindweed is problematic throughout Colorado and can be found throughout the Site. The species is one of the most competitive perennial weeds and can infest a diversity of land and soil types – cultivated areas, pastures, lawns, gardens, roadsides, and waste areas. Field bindweed is an aggressive non-native, deep-rooted, perennial plant, whose seeds can remain viable for up to 40 years in the soil (CDA 2015a). It spreads vegetatively by both long, spreading above-ground vines and below-ground rhizomes, and its difficulty in eradication primarily lies with its large taproot that can grow 20 feet deep. Control Approach Control of field bindweed will likely be a long-term process and should focus on continually stressing the plants and preventing seed set to exhaust the seed bank. Treating as much field bindweed as possible prior to construction will decrease the amount of invading individuals post-construction. Spot treatment of bindweed with herbicides during construction is also highly recommended to prevent new establishment. Mechanical treatment of field bindweed is largely ineffective but can be useful during a large flower flush to prevent seed set. Species-specific biological control agents exist for field bindweed but are not recommended for the Country Club Reserve project due to timing restrictions and the use of herbicides. Pre-Construction • Two herbicide treatments (one just after full-bloom and one in the fall) to eliminate top-growth and prevent seed set. • Spot-treatment of individuals (either mechanically or chemically) during the construction phase. Post-Construction • Establishment of healthy stands of desirable vegetation to out-compete field bindweed. • Mulching exposed non-seeded areas to prevent germination of field bindweed seed or vegetative re-growth. Herbicide Recommendations Table 2 below contains the herbicide recommendations provided by the CDA (2015a) for field bindweed in range conditions. 3.2.3 Leafy Spurge (B List) Species Background Leafy spurge has adapted to a wide variety of habitats in Colorado, though it is more commonly associated with mesic conditions, and effectively crowds out other plant species. Once established, its rapid growth rate, extensive root system, and high seed production rate make it difficult to manage. Leafy spurge is one of the earliest species to emerge in the spring; one large flower can produce up to 130,000 seeds. A patch was identified in the northeast portion of the site and small patches occur sporadically throughout the north-central NHBZ. Control Approach Control of leafy spurge will likely be a long-term process and should focus on continually stressing the plants in order to exhaust energy stores within the root system and preventing seed set to exhaust the seed bank. Treating as much leafy spurge as possible prior to construction will decrease the amount of invading individuals post-construction. Spot treatment of leafy spurge with herbicides during construction is also highly recommended to prevent new establishment. Mechanical treatment of leafy spurge is largely ineffective for long-term control due to the extensive root system, but can reduce seed production if repeated every two to four weeks during the growing season. Pre-Construction • Herbicide treatment in the spring and summer to eliminate top growth. • If possible, plan grading operations to avoid moving leafy spurge-infested soil/subsoil from one location to another on Site to avoid spread by root fragments. • Spot-treatment of individuals (either mechanically or chemically) during the construction phase to further stress plants and prevent seed set. Post-Construction • Establishment of healthy stands of desirable vegetation to out-compete leafy spurge. • Mowing every two to four weeks during the growing season to reduce seed set. • Mulching exposed non-seeded areas to prevent germination of seed or vegetative re-growth. • Spot-treatment of individuals either mechanically or with herbicide during the construction phase to further stress plants or prevent seed set. Herbicide Recommendations Table 3 below contains the herbicide recommendations provided by the CDA (2015b) for leafy spurge in range conditions. 3.2.4 Cheatgrass (C List) Species Background Cheatgrass is a highly adaptable winter annual grass that thrives in arid, semi-arid, and cold environments. It is one of the most competitive non-natives in the Western US; it is present in the drier Uplands on Site. Cheatgrass derives its competitive advantage by emerging very early in the year, producing easily transportable seeds, and altering fire regimes to create a positive fire feedback loop that favors its growth over other species. Seeds can remain viable for up to three years in the soil. Control Approach The control approach focuses on mechanical and cultural methods to remove existing populations, provide competition for resources, and reduce bare ground cover. Mowing is not recommended as the action leave roots behind, stimulate flower production, and disperse seeds. Hand collecting, bagging, and disposal are recommended. Cheatgrass is often a contaminant of purchased seed mixes, straw, and stormwater control materials; care must be taken to purchase weed-free materials. Currently, there are no biological control agents for cheatgrass authorized in Colorado. Pre-Construction • Removal of existing populations by carefully hand-pulling plants without spreading the seed and bagging all parts of the cut plants. • Ensure all materials (seed mixes, straw, stormwater control materials, etc.) are certified weed free, and ensure dirt-moving equipment is washed prior to mobilizing to Site. • Mechanical spot-treatment of individuals during the construction phase to prevent spread. Post-Construction • Establishment of healthy stands of desirable vegetation to out-compete cheatgrass. • Mulching exposed non-seeded areas to prevent germination of seed or vegetative re-growth. • Mechanical spot-treatment of individuals. 3.2.5 Common Mullein (C List) Species Background Common mullein is found throughout Colorado and is most strongly associated with heavily disturbed sites (i.e., roadsides and trails). Common Mullein was not observed in the 2020 evaluation of noxious weeds, but was recorded on Site in 2006 (Walsh 2006). Common mullein is an aggressive non-native, biennial species that reproduces by seed. A seed produces a rosette in the fall or spring during the first year of growth; during the second year the stem bolts, flowers, sets seed, and the plant dies. A single robust plant can produce between 100,000 to 250,000 seeds from June through August. Common mullein is difficult to control given the amount of seed produced and seed bank left in the soil. Control Approach Noxious weed monitoring during the growing season will provide more information on the extent of Common mullein on Site, so that populations can be targeted with the appropriate measures. In most scenarios, the control approach for managing common mullein focuses on preventing seed set. Chemical control is recommended for common mullein. Biological control agents exist for common mullein but have not been approved in Colorado. Pre-Construction • Removal of existing individuals by hand pulling or digging when the soil is moist, prior to flowering. If flowers are present, pull plants carefully and bag them so as not to distribute the seed. • Herbicide application during the rosette phase in spring and/or fall, as well as the bud/early flower stage in the spring. • Spot-treatment of individuals (either mechanically or chemically) during the construction phase to further stress plants and prevent seed set. Post-Construction • Establishment of healthy stands of desirable vegetation to out-compete common mullein. • Mulching exposed, non-seeded areas to prevent germination of seed or vegetative re-growth. Herbicide Recommendations Table 4 below contains the herbicide recommendations provided by the CDA (2009) for common mullein in range conditions. 3.2.6 Musk Thistle (B List) Species Background Musk thistle is found throughout Colorado and is most strongly associated with heavily disturbed sites (i.e., roadsides and trails). Musk Thistle was not observed in the 2020 evaluation of noxious weeds, but was recorded on Site in 2006 (Walsh 2006). Musk thistle is an aggressive non-native, biennial species that reproduces solely by seed. A seed produces a rosette in the fall or spring during the first year of growth; during the second year the stem bolts, flowers, sets seed, and the plant dies. A single robust plant can produce up to 100 heads from May through September, and seeds can mature on severed bud and flower heads. Seeds can remain viable for up to 14 years in the soil. Control Approach Noxious weed monitoring during the growing season will provide more information on the extent of musk thistle on Site, so that these populations can be targeted with the appropriate measures. In most scenarios, Table 4 Herbicide Recommendations for Common Mullein (CDA, 2009) Herbicide Rate1 Application Timing and Restrictions Chlorsulfuron (Telar XP)1-3 oz./acre Apply to rosette stages in spring or fall prior to bolting. Add non-ionic surfactant @ 0.32 oz/gallon water or 1 pint/100 gallon water. 2,4-D Picloram (Grazon P+D)2 4 pints/acre Apply to rosette stages in spring or fall prior to bolting. Add non-ionic surfactant @ 0.32 oz/gallon water or 1 pint/100 gallon water. DO NOT apply near trees, shrubs, or high water table. Picloram (Tordon 22K)2 1-2 quarts/acre Apply to rosette stages in spring or fall prior to bolting. Add non-ionic surfactant @ 0.32 oz/gallon water or 1 pint/100 gallon water. DO NOT apply near trees, shrubs, or high water table. Metsulfuron (Cimmaron)1 oz./acre Apply to rosette stages in spring or fall prior to bolting. Add non-ionic surfactant @ 0.32 oz/gallon water or 1 pint/100 gallon water. 1Rates are approximate and based on equipment with an output of 30 gallons per acre. Read label for exact rates 2This is a Restricted Use Pesticide the control approach for managing musk thistle focuses on preventing seed set. Biological control agents exist for musk thistle but are not recommended for the Country Club Reserve project due to timing restrictions and the use of herbicides. Pre-Construction • Removal of existing individuals by carefully cutting the plant without spreading the seed and bagging all parts of the cut plants. • Herbicide application during the rosette phase in spring and/or fall, as well as the bud/early flower stage in the spring. • Spot-treatment of individuals (either mechanically or chemically) during the construction phase to further stress plants and prevent seed set. Post-Construction • Establishment of healthy stands of desirable vegetation to out-compete musk thistle. • Mulching exposed, non-seeded areas to prevent germination of seed or vegetative re-growth. 3.2.7 Russian Olive (B List) Species Background Russian olive is found throughout Colorado but is most strongly associated with open riparian zones. The north-central NHBZ contains 8 individual Russian Olives along the southern NHBZ-wetland border. Russian olive is an aggressive non-native, perennial tree that frequently sprouts suckers. It has the capability of fixing nitrogen in its roots, and outcompetes native plants by interfering with soil nutrient cycling, constraining natural plant succession, and reducing water availability for other plants. Control Approach The control approach for Russian olive focuses on preventing new establishment of trees. Because plants are already present on Site, the recommended method for control is cut-stump treatments. This treatment constitutes cutting down the tree with a hatchet or chainsaw and immediately applying an approved herbicide to the surface of the stump. This treatment is the most effective if applied in the fall. Pre-Construction • Removal of existing individuals using the cut-stump treatment to prevent suckers and eventual establishment of new trees. Post-Construction • Establishment of healthy stands of desirable vegetation to out-compete Russian olive. • Mulching exposed, non-seeded areas to prevent germination of vegetative re-growth. Table 5 below contains the herbicide recommendations provided by the CDA (2015c) for Russian olive in range conditions. 4.0 WEED MONITORING Noxious and invasive weed monitoring will occur for three years following restoration of the Site. Monitoring methodologies and NHBZ success criteria are presented in the Annual Monitoring and Reporting Plan. Table 5 Herbicide Recommendations for Russian Olive (CDA, 2015c) Herbicide Rate Application Timing and Restrictions Cut stump treatment: Apply to the cambial layer of the tree immediatley after the cut-stump treatment and to roots above the soil surface. Basal bark treatment: Spray the roots above the soil surface, root collar, and lower trunk to a height of 12-15" above the ground until they are wet but not dripping, Glyphosate (Redeo- approved aquatic label)1 Undiluted (100% solution) or 50% solution in basal bark oil. Cut stump treatment: Apply to the cambial layer of the tree immediatley after the cut-stump treatment and to roots above the soil surface. Diluted solutions require regular agitation. Treat summer to fall, with fall being the most effective. 2These are non-selective products and will kill any vegetation contacted. Triclopyr (Garlon 4, Remedy) 20-30% solution in basal bark oil. The herbicide Pathfinder comes pre-mixed in oil and does not require dilution. 5.0 LITERATURE CITED AND DATA SOURCES Cedar Creek Associates, Inc. 2016. Updated Ecological Characterization Study (ECS) Letter Report for the Country Club Reserve Development Parcel. Dated April 19, 2016. City of Fort Collins. 2020. City of Fort Collins Land Use Code. September 2020. Colorado Department of Agriculture (CDA) – Conservation Services. 2008. Canada thistle identification and management. Factsheet. Colorado Department of Agriculture (CDA) – Conservation Services. 2009. Common Mullein identification and management. Factsheet. Colorado Department of Agriculture (CDA) – Conservation Services. 2015a. Field bindweed identification and management. Factsheet. Colorado Department of Agriculture (CDA) – Conservation Services. 2015b. Leafy spurge identification and management. Factsheet. Colorado Department of Agriculture (CDA) – Conservation Services. 2015c. Russian Olive identification and management. Factsheet. Colorado Department of Agriculture (CDA) – Conservation Services. 2019. Cheatgrass identification and management. Factsheet. Colorado State University Extension. 2013. Canada thistle. Fact Sheet No. 3.108. Siegel, S. and Donaldson, S. 2003. Measures to prevent the spread of noxious and invasive weeds during construction activities. University of Nevada Cooperative Extension, Fact Sheet FS-0359. Walsh Environmental Scientists and Engineers, LLC. 2006. Ecological Site Characterization Report. Dated February 2, 2006.