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HomeMy WebLinkAboutTHE MARK - FDP240013 - SUBMITTAL DOCUMENTS - ROUND 2 - Supporting Documentation (4) The Mark Weed Management Plan September, 2024 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 List B Species ........................................................................................................ 5 3.2.1.1 Canada Thistle ...................................................................................................... 5 3.2.1.2 Bull Thistle ............................................................................................................ 6 3.2.1.3 Leafy Spurge ........................................................................................................ 7 3.2.2 List C Species ........................................................................................................ 8 3.2.2.1 Field Bindweed ...................................................................................................... 8 3.2.3 Invasive Weeds ..................................................................................................... 9 4.0 Weed Monitoring and Adaptive Management ............................................................................... 10 5.0 Literature Cited and Data Sources .............................................................................................. 11 The Mark Weed Management Plan 1.0 INTRODUCTION A Weed Management Plan provides a framework control noxious and invasive weeds in a restoration project. Effectively controlling or managing noxious and invasive weeds is vital to achieve desirable vegetative outcomes. Noxious and invasive weeds can fill niches and outcompete desirable species for limited resources, such as plant available water and sunlight. The goal of this Weed Management Plan is to provide guidance on specific weed treatments. Adaptive management is the key to an effective weed management program. Strategic inspections should be implemented to inform management activities to ensure that weed control treatments occur within appropriate time frames to maximize the benefits. 2.0 EXISTING CONDITIONS A field evaluation of noxious and invasive weeds was implemented in July 2024. The site was abandoned by the previous developer and noxious and nuisance weeds domina te the project area. The noxious weeds observed on site were Canada thistle (Cirsium arvense [List B]), Leafy Spurge (Euphorbia esula [List B]), bull thistle (Cirsium vulgare [List B]), and bindweed (Convolvus arvensis [List C]) Annual weeds observed in the project area were prickly lettuce (Lactuca serriola), burning bush (Kochia scoparia), and annual sunflower (Helianthus annus). Noxious weeds are characterized into three categories , in accordance with the Colorado Noxious Weed Act. • 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 B and C species is recommended but not required by the state. However, local governing bodies, such as the County or City of Fort Collins, may require management. For the purposes of this report, an invasive weed is a non-native (or alien) whose introduction can causes economic or environmental harm. Invasive weeds are typically annual or biennial plant species which produce large quantities of seed, thrive on disturbed soil, have aggressive root systems and often grow so densely that they smother the root systems of surrounding vegetation. The establishment and persistence of invasive species can be a significant obstacle to restoration success. 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. Noxious and invasive weeds are opportunistic and take advantage of open niches to flourish. The best way to prevent establishment and persistence of weedy species is to limit their opportunities by implementing best management practices and ensuring that disturbed ground is not left fallow so that weedy species can take hold. 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. City of Fort Collins staff will inspect equipment. • 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. City of Fort Collins staff will inspect materials used for restoration. • 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 Each year weed management and treatment approaches should be tailored to on the ground conditions. Noxious and invasive weed inventory and mapping can provide vital information for developing a control strategy. Site conditions along with project goals must be considered when developing, implementing, and adapting an effective weed management plan. A qualified herbicide applicator will be used to apply herbicide to control noxious and invasive weeds on the Site. The qualified herbicide applicator 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 List B Species 3.2.1.1 Canada Thistle 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. • Chemical Control – The following herbicide recommendation should be implemented when general herbicide applications are not achieving the desired control . Milestone has been shown to be very effective in managing Canada thistle in the region. Aminopyralid (Milestone)2 5-7 oz. product/acre + 0.25% v/v non- ionic surfactant OR 1 teaspoon product/gal water + 0.32 oz./gal water Apply in spring at the pre-bud growth stage until flowering and/or to fall regrowth. Can also add chlorsulfuron (Telar) at 1 oz./acre to the mix. • Mechanical Control - Mowing of large populations, prior to seed set, can help prevent the expansion of existing populations. Hand pulling of Canada thistle may be appropriate if only a single or very few individuals are observed. All flowerbuds and heads must be collected, bagged, and disposed of or destroyed; seeds will mature and germinate if left on the ground. • Biological Control - Biological control agents exist for Canada thistle but are not recommended for the project due to timing restrictions and the use of herbicides. • Other Management Considerations: o Establishment of healthy stands of desirable vegetation to out -compete Canada thistle. Seeding of native grasses will provide competition for resources . o Mulching exposed, non-seeded areas to prevent germination of seed or vegetative re- growth. 3.2.1.2 Bull Thistle Bull thistle invades dry to moist environments. It prefers nitrogen -rich soils, and it grows on gravelly to clay-textured soils It thrives in areas such as pastures, overgrazed rangeland, roadsides, and disturbed areas. Maintaining healthy ecosystems, guarding against disturbance or overuse is the best prevention measure against bull thistle. As with most biennials, limiting seed production is critical to effective control. Chemical control is the most effective and efficient method of eradication if applied during the rosette stage, spring or early fall. To reduce seed production, plants with buds or flowers should be collected and bagged, disposed of or destroyed. • Chemical Control - The following herbicide recommendation should be implemented when general herbicide applications are not achieving the desired control • Mechanical Control - Methods, such as hoeing, tilling and digging, are best for infestations smaller than 0.5 acres. Mowing, chopping and deadheading stimulates more flower production; these methods require consecutive years of season long treatments . • Biological Control - There are no reasonable biological control agents for this species. • Other Management Considerations: o Establishment of healthy stands of desirable vegetation to out -compete pepperweed. Seeding of native grasses will provide competition for resources. o Mulching exposed, non-seeded areas to prevent germination of seed or vegetative re- growth. Aminopyralid (Milestone)2 5-7 oz. product/acre + 0.25% v/v non- ionic surfactant OR 1 teaspoon product/gal water + 0.32 oz./gal water Apply in spring at the pre-bud growth stage until flowering and/or to fall regrowth. Can also add chlorsulfuron (Telar) at 1 oz./acre to the mix. 3.2.1.3 Leafy Spurge Leafy spurge has adapted to a wide variety of habitats in the state and is very competitive with other plant species. Where it becomes established in rangeland, pasture, and riparian sites, it crowds out practically all other vegetation. The competitive, rapidly growing, and extensive root system makes leafy spurge very difficult to manage. The most effective method of control for leafy spurge is to prevent its establishment through proper land management. Early detection and removal of plants if found, is the key to prevention. Planting desirable and competing grasses and forbs can aid in limiting the spread of leafy spurge. Herbicide treatments are a good option if used during the bud to flowering stage of the plant. Once established, containment is key. • Chemical Control - The following herbicide recommendation should be implemented when general herbicide applications are not achieving the desired control. • Mechanical Control - Due to the extensive root system, hand- pulling this plant is not a viable option. Mowing will reduce seed production if repeated every 2 to 4 weeks during the growing season, but will provide little long-term control. • Biological Control - Both sheep and goats can be effective grazers of leafy spurge. The flea beetles Apthona nigriscutis, A. lacertosa, and A. cyparissiae, are effective especially when combined with grazing and/or herbicides. • Other Management Considerations: o Establishment of healthy stands of desirable vegetation to out -compete leafy spurge. Seeding of native grasses will provide competition for resources. o Mulching exposed, non-seeded areas to prevent germination of seed or vegetative re- growth. Aminocyclopyrachlor + chlorsulfuron (Perspective)2 + Diflufenzopyr + dicamba (Overdrive, Distinct) 3-4 oz. Perspective/acre + 4 oz. Overdrive/acre + 1% v/v methylated seed oil  Apply at flowering in the spring and/or fall. Quinclorac (Paramount, Facel-L, Quinstar) + Diflufenzopyr + dicamba (Overdrive, Distinct) 12-24 oz. Quinstar/acre + 4 oz. Overdrive/acre + 1% v/v methylated seed oil Apply at flowering in the spring and/or fall. Aminocyclopyrachlor + chlorsulfuron (Perspective)2 4.75-8 oz. product/acre + 1% v/v methylated seed oil Post-emergence in spring until flowering, or to fall rosettes.  1Rates are approximate and based on equipment with an output of 30 gallons per acre. Read label for exact rates 2Applications greater than 5.5 ounces/acre exceeds the threshold for selectivity. DO NOT treat in the root zone of desirable trees and shrubs. Perspective is not for use on grazed or feed forage. 3.2.2 List C Species 3.2.2.1 Field Bindweed 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. Spot treatment of bindweed with herbicides during construction is also highly recommended to prevent new establishment. In general, field bindweed is very difficult to control. • Chemical Control - The following herbicide recommendation should be implemented when general herbicide applications are not achieving the desired control. Quinclorac (Paramount, Facel-L, Quinstar) 12-24 oz. quinclorac/acre Apply at flowering in the spring and/or fall. • Mechanical Control – Mechanical methods of control are generally ineffective. Cutting, mowing, or pulling has a negligible effect unless the plants are cut below the surface in the early seedling stage. • Biological Control - The bindweed gall mite, Aceria mahlerbae, has proven to be effective in reducing field bindweed infestations. • Other Management Considerations: o Establishment of healthy stands of desirable vegetation to out -compete field bindweed. o Mulching exposed, non-seeded areas to prevent germination of seed or vegetative re- growth. 3.2.3 Invasive Weeds Control of invasive weeds, such as aggressive, non-native annual and biennial species, is very difficult because chemical control methods typically have collateral damage to native species establishment. Cultural control, through the establishment of competitive and desired vegetation, prevents or slows down invasion by weedy species and is a key component of successful weed management. Weeds are typically opportunistic and readily invade disturbed sites. Controlling weeds on such sit es can be futile without vegetative restoration, as weeds will readily re-invade the disturbed area. In certain situations, mowing may be useful, especially when invasive weeds are so dominant that they are outcompeting desirable species for limited resources, such as sunlight and plant available water. However, use of mowing should be carefully considered prior to implementation since there are potential implications on establishing desirable vegetation. Application of the herbicide dicamba, our other general herbicides, can be used if invasive weeds become dominant. Dicamba is a selective herbicide used for post-emergent control of broadleaf weeds. Dicamba is a highly volatile chemical that can damage non -target plant species through spray drift, so it should only be used in appropriate situations. 4.0 WEED MONITORING AND ADAPTIVE MANAGEMENT Noxious and invasive weed monitoring is vital to an effective weed management plan. Therefore, site inspections for weed inventory and mapping will occur in the April, June, and August during construction and continuing into the post-construction period, if necessary. This information will be used to evaluate the effectiveness of control and develop a weed management workplan for the coming months. The workplan will be based on site specific conditions and prioritize weed management strategies based on over all risk to restoration goals. In order to complete effective weed control, the recommendations presented in the workplans should be fully implemented. Over the span of the monitoring period, the weed mapping efforts will show whether weed control efforts are effective. If requested, an annual report describing weed management activities can be provided to the city by the end of the year. 5.0 LITERATURE CITED AND DATA SOURCES Colorado Department of Agriculture (CDA) – Conservation Services. Noxious Weed Factsheets. 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.