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drained pasture areas.Such swales are often dominated by this grass which is palatable to livestock early in the season,but the
<br /> awns of mature plants can be injurious to the mouth,throat,nose and eyes of livestock.There are currently no selective herbicides
<br /> for controlling foxtail barley in pasture.Glyphosate(Roundup and others)can kill the plants,and would take out any desirable
<br /> grasses as well.Tillage can be used to non-selectively take out infestations of foxtail barley.But even after re-seeding such areas
<br /> with desirable pasture grasses,foxtail barley will eventually come back in if the soil remains poorly drained and saline conditions
<br /> favor foxtail barley over other grasses.
<br /> Milkweed(Asclepias spp)—Showy milkweed is a native perennial frequently found in pastures and on roadsides in Larimer
<br /> County.Plants grow to 5 feet tall,contain a milky latex,and produce large,spiny seedpods in late summer.Seed is dispersed in
<br /> windborne clusters of cotton-like pappus.The densest infestations of milkweed typically occur on poorly drained sites due to the
<br /> plant's tolerance of alkaline soils.Though not palatable,milkweed is toxic to livestock.In areas where control is desired,
<br /> applications of Tordon or dicamba(Vanquish,Banvel,Clarity)can provide selective control.
<br /> Pigweed (Amaranthus spp)—Pigweed species most common in Larimer County are redroot,tumble and prostrate pigweed.
<br /> These species are non-native annuals that germinate in May and set seed by August.Pigweed is a problem primarily in crop
<br /> production,but can be found in abandoned fields and run-down pastures.The most effective herbicides for control are Milestone,
<br /> Telar,Vista or dicamba+2,4-D-product names Outlaw,Rangestar,Veteran 720,Weedmaster and others.
<br /> Poison ivy(Toxicodendron rvdbergii)—Poison ivy is a native perennial vine-shrub that can be found in a variety of habitats in
<br /> Larimer County.The leaflets are arranged in characteristic groups of 3 and often have reddish coloration and tend to droop.
<br /> Because of the toxic residue that causes severe skin rash,poison ivy is seldom a desirable plant.Best products for control are
<br /> dicamba(Banvel,Clarity,Vanquish),Garlon,Milestone,and Redeem.
<br /> Prickly lettuce(Lactuca serriola)—Prickly lettuce is a non-native biennial plant that can grow to 5 feet tall.Prickly lettuce
<br /> grows from a taproot,producing small yellow flowers in mid-summer.The stems contain a milky juice.At maturity the seeds
<br /> disperse in puffballs,much like a dandelion.Prickly lettuce is an invader of abandoned fields,roadsides and run-down pastures.
<br /> Best control provided by applications of Escort,dicamba(Banvel,Clarity,Vanquish),Garlon,Milestone,Redeem,Vista,Telar,or
<br /> Transline.
<br /> Rabbitbrush (Chrysothamntts nattseosus)—Rabbitbrush is a common name for 12 species in the western United States.The
<br /> species most common in Larimer County is gray or rubber rabbitbrush.This native perennial shrub can grow to 4 feet tall,thriving
<br /> on dry sites.Unpalatable to horses and cattle,rabbitbrush can dominate over-utilized pastures.Controlling rabbitbrush is difficult.
<br /> Spot-spraying individual plants with a non-selective herbicide,such as Arsenal,is most effective.
<br /> Ragweed (Ambrosia artemisiifolia)—Ragweed species common in Colorado are western and giant ragweed.Western ragweed
<br /> is most common in Larimer County.These plants are native annuals that produce a pollen causing hay fever.Ragweed is not
<br /> highly competitive or invasive.In areas where control is desired,applications of Curtail,Milestone,Redeem,Vista,or dicamba+
<br /> 2,4-D-product names Outlaw,Rangestar,Veteran 720,Weedmaster and others.
<br /> Rye(Secale cereale)—Rye is a cereal crop that has escaped into natural areas,pastures and roadsides and become a weedy
<br /> species.Referred to as feral rye or volunteer rye,this grass is highly competitive and difficult to control.The life cycle of feral rye
<br /> is the same as cheatgrass,winter wheat,and other species known as'winter annuals'.This cycle begins with germination in late
<br /> summer or early fall(some spring germination can occur as well),over-wintering as a green grass,and resumption of growth in
<br /> the spring.Winter annuals set seed and complete their life cycle by mid-summer.Feral rye has grazing value in the spring,but the
<br /> invasive character of this grass over-rides such value.If left unchecked,feral rye can dominate the plant community and is a
<br /> wildfire hazard.Most effective control is Landmark or Oust(read label carefully for application within appropriate areas)or an
<br /> application of glyphosate(Roundup and other brand names)at a rate and timing that is not injurious to desirable perennial grasses.
<br /> Other selective herbicides are being investigated by Colorado State University and the Larimer County Weed District.
<br /> Recommendations are available yet best practice would be to set up a site visit with a Weed Specialist to insure best management.
<br /> Smooth brome(Bromtts inermis)—Smooth brome is anon-native perennial grass commonly utilized for hay and forage
<br /> production in Larimer County.Smooth brome is a sod-forming plant that,once established,is extremely competitive and is often
<br /> found in pure stands.Smooth brome's competitive ability and invasiveness has made this grass undesirable in areas where
<br /> establishment of a native plant community is desired.Control is difficult and may require 2 or more applications of glyphosate
<br /> (Roundup and others).In some cases,moldboard plowing,or complete turnover of the soil to disrupt the extensive underground
<br /> root system is necessary,in addition to glyphosate applications.
<br /> Sunflower(Helianthus spp)—Sunflower species common in Larimer County are prairie sunflower and common sunflower.
<br /> These native annuals can grow to 10 feet tall under favorable conditions.In situations where dense stands of sunflower are
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