HomeMy WebLinkAboutSEVEN GENERATIONS MULTIFAMILY - FDP230008 - SUBMITTAL DOCUMENTS - ROUND 2 - ENVIRONMENTAL REPORT
Eastbrook
Weed Management Plan
March 2023
PO Box 272150
Fort Collins, CO 80527
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Table of Contents
INTRODUCTION ...................................................................................................................................... 1
EXISTING CONDITIONS ...................................................................................................................... 1
WEED MANAGEMENT ............................................................................................................................ 3
Best Management Practices ........................................................................................................... 3
Weed Treatment Options and Recommendations ................................................................. 3
List B Species ................................................................................................................................... 5
1.1.1.1 Canada Thistle .............................................................. Error! Bookmark not defined.
1.1.1.2 Leafy Spurge ................................................................................................................ 7
List C Species ................................................................................................................................... 8
1.1.1.3 Field Bindweed ............................................................. Error! Bookmark not defined.
Invasive Weeds ............................................................................................................................... 9
WEED MONITORING AND ADAPTIVE MANAGEMENT ................ Error! Bookmark not defined.
LITERATURE CITED AND DATA SOURCES ................................................................................... 11
Eastbrook
Weed Management Plan
1.0 INTRODUCTION
A Weed Management Plan provides a framework to control noxious and invasive weeds in a restoration
project. Effective control or management of noxious and invasive weeds is vital to achieve desirable
restoration 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.
2.0 EXISTING CONDITIONS
A field evaluation of noxious and invasive weeds was implemented in June 2022 by Craig Severn (Ecologist)
with Blue Mountain Environmental Consulting. A parking lot borders this undeveloped lot, which is next to
an existing multi-business office building. The main portion of the lot to be developed consists of a mix of
forbs and grasses. 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 biocontrol 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 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.
For the purposes of this report, an invasive weed is a non-native (or alien) whose introduction can cause
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.
The field survey revealed the presence of the following species:
• List A Species
o None
• List B Species
o Canada Thistle (Cirsium arvense)
o Leafy Spurge (Euphorbia esula)
• List C Species
o Field Bindweed (Convolvulus arvensis)
3.0 WEED MANAGEMENT
3.1 Best Management Practices
Noxious weeds are common in urban and developed areas. Construction-related ground disturbances
facilitate and create ideal conditions for the spread of noxious weeds. Some common nuisance weeds such
as kochia (Bassia scoparia) and Russian thistle (Salsola tragus) can be the dominate species on a site, and
should be included in management plans. Nevertheless, there are some general practices that can be
followed to limit the spread and/or establishment of noxious and nuisance 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
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 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, 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 (Cirsium arvense)
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 - Table 1 displays herbicide recommendations which could be used for chemical
control.
• 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 flower buds 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 Eastbrook 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.
Table 1 Herbicide Recommendations for Canada Thistle (CDA 2015)
Herbicide Rate1 Application Timing and Restrictions
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.
Clopyralid +
Triclopyr (Prescott;
Redeem; others)
3 pints product/acre
+ 0.25% v/v non-
ionic surfactant OR
1.25 oz. product/gal
water + 0.32 oz./gal
water
Apply until flowering and/or fall regrowth.
Aminocyclopyrachlor +
chlorsulfuron (Perspective)2
5.5 oz. product/acre
+ 0.25% v/v non-
ionic surfactant
Apply to spring rosette to flower bud growth stage; or fall.
IMPORTANT: Applications greater than 5.5 oz. product/acre
exceeds the threshold for selectivity. DO NOT treat in the root zone
of desirable trees and shrubs. Not for use on grazed or feed
forage.
Picloram2 (Tordon/Picloram
22K - Restricted use pesticide)
1 qt./acre + 0.25%
v/v non-ionic
surfactant OR 1.0
oz./gal water + 0.32
oz./gal water
Spring to early flower bud stage and/or fall regrowth. DO NOT use
near trees, desirable shrubs, water, or high water table.
1Rates are approximate and based on equipment with an output of 30 gallons per acre. Read label for exact rates
2Product not permitted for use in the San Luis Valley
3.2.1.2 Leafy Spurge (Euphorbia esula)
Since leafy spurge is competitive, grows rapidly, and has an extensive root system, it can be very difficult
to manage. Therefore, the Weed Management Plan must use several control methods that are compatible
with the project site.
• Chemical Control - Table 2 displays herbicide recommendations which could be used for chemical
control. Treating as much leafy spurge as possible prior to construction will decrease the number
of invading individuals’ post-construction.
• Mechanical Control - Mechanical treatment of leafy spurge is largely ineffective for long-term
control due to the extensive root system, but it can reduce seed production if repeated every two
to four weeks during the growing season.
• Biological Control - The flea beetles Apthona nigriscutis, A. lacertosa, and A. cyparissiae, are
effective at controlling leafy spurge, especially when combined with grazing and/or herbicides.
• Other Management Considerations:
o Establishment of healthy stands of desirable vegetation to out-compete leafy spurge.
o Mulching exposed, non-seeded areas to prevent germination of seed or vegetative re-
growth.
Table 2 Herbicide Recommendations for Leafy Spurge (CDA 2015)
Herbicide Rate1 Application Timing and Restrictions
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.
Imazapic (Plateau, Panoramic)
12 oz./acre or 0.4
oz./gal water + 1%
v/v methylated seed
oil
Fall only treatment prior to hard freeze. Imazapic can injure some
grasses. Repeat treatment over several years may be necessary.
Picloram
(Tordon/Picloram 22K -
Restricted use
pesticide) + 2,4-D
1 qt. picloram/acre +
1 qt./acre 2,4-D +
0.25% v/v non-ionic
surfactant
Just after full-bloom in the spring and/or fall. DO NOT use near
trees, desirable shrubs, water, or high water table.
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 (Convolvulus arvensis)
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 number of invading individuals’ post-construction. Spot treatment of field
bindweed with herbicides during construction is also highly recommended to prevent new establishment.
• Chemical Control - Table 3 displays herbicide recommendations which could be used for chemical
control.
• 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.
Table 3 Herbicide Recommendations for Field Bindweed (CDA 2015)
Herbicide Rate1 Application Timing and Restrictions
Clarity + 2,4-D Amine 1 quart/acre, or 1
ounce/gallon water
Just after full bloom and/or fall. DO NOT apply near or under
trees/shrubs or where soils have rapid permeability. DO NOT apply
when outside temperatures will exceed 85°F. Add ionic surfactant
@ 0.32 ounces/gallon water or 1 quart/100 gallons water.
Tordon 22K (Restricted Use
Pesticide)
2 quart/acre, or 1
ounce/gallon water
Just after full bloom and/or fall. DO NOT apply near or under
trees/shrubs or where soils have rapid permeability. Add ionic
surfactant @ 0.32 ounces/gallon water or 1 quart/100 gallons
water.
Roundup Ultra (non-selective,
will kill all vegetation)
4-5 quarts/acre, or 4-
5 ounces/gallon
water
Just after full bloom and/or fall. Add ionic surfactant @ 0.32
ounces/gallon water or 1 quart/100 gallons water. Use caution
when applying near grasses or other desirable vegetation.
1Rates are approximate and based on equipment with an output of 30 gallons per acre. Read label for exact rates
3.2.3 Invasive Weeds
Control of invasive (nuisance) 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 sites 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.
4.0 WEED MONITORING AND ADAPTIVE MAANGEMENT
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 and September for three years following
seeding. 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 overall 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 biannual mapping efforts will show whether weed control
efforts are effective.
5.0 LITERATURE CITED AND DATA SOURCES
Blue Mountain Ecological Consulting. 2022. Ecological Characterization Study for 3221 Eastbrook Drive.
June, 2022.
City of Fort Collins. 2022. City of Fort Collins Land Use Code. March 1, 2022.
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.