Eligible Noxious Weeds and Treatment Options

Bull thistle: Flowers arranged in a raceme; flower is gum-drop shaped; base of leaves clasp the stem & extend down the stem to node below; top surface of leaves have stiff, rough hairs

Scotch thistle: Pitted fleshy flower receptacle; prominent mid-rib; wide lobed leaves; wide spiny wings extend the length of the stem

Musk thistle: Leaf with white midrib & leaf margins with spines; pappus with plumose barbed bristles; wide, stout lance-shaped bracts with spiny tips

Biennial

• Aminopyralid (Milestone)

• Chlorsulfuron (Telar XP)

• Clopyralid (Transline)

• 2,4-D

• Glyphosate

Easily establishes in disturbed areas. Treat rosette or when bolting.

Late applications can cause thistles to produce seeds more quickly before herbicide can take effect.

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Leaves are oblong, spiny, bright green, and slightly hairy on the undersurface. Unlike other noxious biennial thistles, Canada thistle flowers occur in small clusters of 1 to 5 flowers. They are about 1 cm in diameter, tubular shaped, and vary from white to purple in color.

Deep-rooted perennial

Due to extensive root system, hand-pulling and tilling create root fragments and stimulate growth, mowing can be effective if done every 10 to 21 days throughout growing season

• Aminopyralid (Milestone)

• Clopyralid + Triclopyr (Prescott; Redeem; others)

• Aminocyclopyrachlor + chlorsulfuron (Perspective)

Click here for photos and more information about Canada thistle

Stem leaves are alternate and oblong. Leaves are deeply divided, with four to ten pairs of leaflets, with button-like, perfect disc flowers

Perennial

Remove all root biomass or sever roots below the soil surface early in the season

Mowing, chopping, hand-pulling, and deadheading leaves roots behind and can disperse seeds, expanding the infested area.

• Aminocyclopyrachlor + chlorsulfuron (Perspective)

• Aminopyradlid + Metsulfuron (Opensight)

• Metsulfuron (Escort  XP)

Apply Late spring to mid-summer

Click here for photos and more information about Common tansy

Common teasel - produces more than 2,000 seeds per plant. The flowers are purple or white with spiny, awned bracts at the base. The flower head is generally egg-shaped, with a square base

Cutleaf teasel - Flower heads are cream to white and bloom from the center of the head first.The green floral bracts are fused at the base, forming a cup. The bracts on cutleaf teasel are wider and generally shorter than the entire length of the flower head.

Biennial

Mechanical methods are best for infestations smaller than 0.5 acres; Mowing, chopping, and deadheading stimulate more flower production; these methods require consecutive years of season-long treatments.

Flower heads must be collected, bagged, and disposed of or destroyed;

• Metsulfuron (Escort  XP)

• Aminopyralid (Milestone)

• Imazapic (Plateau)

Click here for photos and more information about Common teasel

The stems, in the rosette stage, may grow up to 2 inches in height and produce lance-shaped grayish-green leaves. The plant has numerous small, white flowers with 4 petals on stalks radiating from a stem.

Creeping perennial

• Chlorsulfuron* (Telar)

• Metsulfuron (Escort  XP)

Imazapic (Plateau,  Panoramic)

Click here for photos and more information about Hoary cress/white top

Panicles of reddish-purple flowers with 5 petals & 5 soft, hairy sepals; velcro-like seeds with 4 nutlets

Biennial

Hand-pulling or separating root from upper biomass is recommended

• Metsulfuron (Escort XP)

• Chlorsulfuron (Telar XP) + 2,4-D

• Metsulfuron + Chlorsulfuron (Cimarron X-tra)

Apply to rosette before bolting

Click here for photos and more information about Houndstongue

Can grow up to 3 feet tall on rigid stems that are openly branched on the upper half of the plant. Urn-shaped flowers are solitary on the tip of each branch. Flowers are pink to purple and rarely white

Perennial forb

Mechanical treatments are considered effective before flowering

• Aminopyralid (Milestone)

• Chlorsulfuron (Telar XP)

• Clopyralid (Transline)

• Clopyralid + 2,4-D (Curtail)

Click here for photos and more information about Hybrid knapweed

Yellow snapdragon-like flowers with deep orange centers; stems are woody at the base and smooth at the top, leaves are narrow, linear 1-2 in long

Perennial

Mechanical and grazing are not recommended (toxic to grazers)

• Aminopyralid (Milestone), 2,4-D

• Aminocyclopyrachlor + Chlorsulfuron (Perspective)

• Telar XP (Chlorsulfuron)

Applications in Spring or Fall

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Stiff short hairs evenly spaced on the margins of leaf blades; evenly spaced hairs are on auricles, leaf sheath & ligules; spikelets fit in a zigzag pattern in a cylindrical shape

Winter annual

Mechanical treatments are not recommended

• Glyphosate (Roundup)

• Imazapic Glyphosate (Journey)

• Imazapic (Plateau, Panoramic)

• Aminocyclopyrachlor + Chlorsulfuron (Perspective)

Apply before spikelets begin to form (early Spring)

Pre-emergents must be applied before seed germination (late summer, early fall)

Click here for photos and more information about Jointed Goatgrass

15-30 white ray flowers on flowerheads that are 1-2” in diameter; rosette & lower leaves are spoon-shaped & toothed; upper leaves on the stem are narrow, toothed, & clasp the stem

Creeping perennial

Small infestations can be controlled by hand-pulling

• Aminopyralid (Milestone),

• Melsulfuron (Escort XP),

• Chlorsulfuron (Telar XP)

Apply before flowering in the Spring or early Summer

Click here for photos and more information about Oxeye daisy

Growing 1 to 5 feet high, pepperweed has tiny white flowers. The flowers have four spoon-shaped petals in dense, rounded clusters on branch tips of erect stems. Stems emerge from deep, thick, woody root stocks that can penetrate 10 feet into the soil.

Perennial forb

Due to the deep, brittle root, most mechanical methods are not recommend

• Chlorsulfuron* (Telar)

• Metsulfuron (Escort  XP)

• Imazapic (Plateau,  Panoramic)

Apply when plant is in the early flower to flowering growth stages. (Early spring to early summer)

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Russian knapweed can grow up to 3 feet in height. The flowers are urn-shaped, pink to purple in color, and are solitary at the tips of the upper branches. Russian knapweed can be distinguished from other knapweeds by the smooth, papery, rounded bracts that surround the flowers.

Perennial

Mowing several times before the plants bolt stresses Russian knapweed; however, mowing alone will not eliminate the infestation, and it can stimulate shoot sprouting the following year.

• Aminopyralid*  (Milestone)

• Aminocyclopyrachlor + Chlorsulfuron

• (Perspective)*Aminopyralid* (Milestone) + Chlorsulfuron** (Telar)

Picloram* (Tordon/Picloram 22K - Restricted use pesticide)

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Deciduous evergreen shrub or small tree that grows from 5 to 20 feet tall. The bark on saplings and stems is reddish-brown. The leaves are small, scale-like and bluish-green in color. Tiny pink to white flowers have five petals and grow on slender racemes.

Recommend: Cut-Stump Method

• Triclopyr (Garlon 4,  Remedy)

• Glyphosate* (Rodeo - approved aquatic  label)

Triclopyr (Garlon 4,  Remedy) +  Aminopyralid  (Milestone)

Click here for photos and more information about Tamarisk/Saltcedar

Plants range from 6 to 30 inches tall. Leaves originate from the base of each stem and are grasslike, smooth, glossy, and folded lengthwise. Flowers are yellowish-brown in color and appear from June to October.

Perennial

Hand pull small nutsedge plants when they have less than 6 leaves, which is before tubers form. This is approximately every 2 to 3 weeks during the growing season; over time, this will deplete energy reserves in the roots. Tilling can potentially spread tubers.

• Halosulfuron (Sandea  75DF)

• Glyphosate*  (Roundup)

• Sulfentrazone

2 or 3 treatments in June and July over 2-3 years

Click here for photos and more information about Yellow nut-sedge

Plant is prostrate, spreading into mat form; stems can grow 1-5 ft long; leaflets containing 5-8 oval leave; leaves hairy and opposite; yellow flowers with 5 petals; seed capsule is hard and contains many spines

Annual, germinates in late June-July

Hand-pulling and bagging is recommended; be sure to reduce spreading of seeds

• 2,4-D + Dicamba

• Chlorsulfuron (Telar XP)

• Pendimethalin (Pendulum)

Pre-emergent treatments require precipitation to reach seeds in soil.

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Eurasian watermilfoil is an aquatic plant with feathery underwater foliage. The plant roots on the bottom, but survives and is spread as free-floating plants waiting to take root. The leaves each have 12 to 21 pairs of leaflets and are 1 inch long.

Use of mechanical methods come with a high risk of spreading infestations since Eurasian watermilfoil fragments and roots easily. Such methods should be used only in closed systems, such as ponds, with no outlet, or in limited situations.

• 2-4-D (Aqua-Kleen, Navigate, DMA 4 IVM; Use only aquatic-approved products)

• Fluridone (Sonar or Avast)

• Imazamox (Clearcast)

• Triclopyr (Renovate 3)

Click here for photos and more information about Eurasian watermilfoil

Flowers are yellow to white in color with 5 petals that have purple centers and are 2 to 3 cm in diameter. Stems are erect and stout, reaching 0.61 to 1.5 m tall. Leaves initially develop as a basal rosette. Mature leaves are not hairy, oblong in shape, and have toothed margins. They are also 8 to 45 cm long and 3 to 15 cm wide.

Biennial forb

Mechanical methods can be effective, especially in residential areas and small infestations. The key is to sever roots below the soil surface in the first year or early in the second season before the plant flowers.

Collect, bag, and dispose of all flowers and fruits.

• Aminopyralid (Milestone)

• Metsulfuron (Escort XP)

• Chlorsulfuron* (Telar)

Click here for photos and more information about Moth mullien

Receptacle is solid in the center, cone-shaped and naked; phyllaries are oblong, green in center, and dried on margins, alternate leaves are bipinnatifid, fibrous roots

Annual, biennial, & perennial

Mechanical treatments are effective as long as removal is performed before seeding

• Metsulfuron (Escort XP),

• Chlorsulfuron (Telar XP),

• Aminopyralid (Milestone)

Apply to rosette or when bolting

Click here for photos and more information about Scentless chamomile

Three lobed ray flowers; pungent odor; narrow cone-shaped receptacle with chaff-few long hairs; imbricate phyllaries with hairs; alternate leave are bi- to tripinnatifid; fibrous taproot

Annual, biennial, & perennial

Mechanical treatments are effective as long as removal is performed before seeding

• Metsulfuron (Escort XP),

• Chlorsulfuron (Telar XP),

• Aminopyralid (Milestone)

Apply to rosette or when bolting

Click here for photos and more information about Mayweed chamomile

The tree can reach up to 30 feet with branches with 1 to 2-inch thorns. Leaves are 2 to 3 inches long, alternate, and narrow. Plant has olive-shaped fruits, which are silvery at first, then yellow-red when mature.

Perennial tree or shrub

Recommend: Cut-Stump Method

• Garlon 3A (Triclopyr) or Habitat (Imazapyr)

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Wild caraway is a prolific seed producer; under ideal conditions, each plant can produce several thousand seeds. Stem leaves are finely divided, and resemble those of carrots in shape but tend to droop more. Shoot leaves are alternate and normally oblong or oval in shape. Flowers are white or pinkish in color, small, and occur in terminal or lateral loose clusters at the top of stems. Mature plants are 1 to 3 feet tall and have one or more shoots emerging from a single taproot.

Biennial or sometimes perennial forb

Mechanical methods are best for residential areas and small infestations. Sever roots below the soil surface early in the season, before the plant stores energy, and before seed production.

• Aminopyralid + Metsulfuron (Opensight)

• Metsulfuron (Escort XP) + 2,4-D

• 2,4-D

Click here for photos and more information about Wild caraway