Weed Dept  
 

Noxious Weed Identification

Proper weed identification is paramount to proper weed control. Properly identifying plants can help you avoid costly mistakes such as choosing the wrong herbicide or potentially causing harm to beneficial plants. It is the responsibility of each landowner in Utah to identify and control the noxious weeds on their own properties. Below are listings and photographs of all State and County noxious weeds and some important invading weeds that are important for Basin residents to know about.

What makes a weed a "noxious weed?" The Utah Department of Agriculture and Food defines a noxious weed as "Any plant the commissioner (Commissioner of Agriculture) determines to be especially injurious to public health, crops, livestock, land, or other property." See the Utah Noxious Weed Act 4-17-2.

The following state and county noxious weeds must be controlled by law (Utah Noxious Weed Act R68-9, Utah Code Annotated title 4 Chapter 17 and the Uintah County Weed Control Rules and Regulations).

The "invasive weed species," listed below right, are not required by law to be controlled, however, identification of these weeds may be important to your personal weed management goals.

This list may be altered at any time.

The State of Utah recently updated its noxious weed list. As of 2016, Utah lists a total of 54 weeds on the noxious weed list. Additionally these weeds have been newly classified into the following five categories:

1A = Not known to exist in Utah. Significant risk of invasion.
1B = Limited distribution in Utah. EDRR (Former A Class)
2 = Widely distributed in Utah, considered controllable (Former B Class)
3 = Widely distributed in Utah, considered beyond control, control expansion (Former C Class)
4 = Present in Utah. Prevent distribution through Seed law

Each county in Utah may have different priorities regarding specific State designated Noxious Weeds and therefore may reprioritize these weeds as they see fit for their own needs.

Please note these links have multiple photos and may take several seconds to load for slower connection speeds.

Class 1A Weeds

No Image African rue No Image Common crupina No Image Malta starthistle No Image Mediterranean sage No Image Plumeless thistle
No Image Small bugloss No Image Spring millet No Image Syrian beancaper No Image Ventenata  

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Class 1B Weeds

No Image African Mustard No Image Blueweed (Vipers bugloss) St. Johnsort Common St. Johnswort No Image Camelthorn
No Image Cutleaf vipergrass No Image Elongated mustard No Image Garlic mustard No Image Giant reed
Goatsrue Goatsrue No Image Japanese knotweed Oxeye Daisy Oxeye Daisy No Image Purple starthistle

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Class 2 Weeds

Black Henbane Black Henbane Diffuse Knapweed Diffuse Knapweed Dalmatian Toadflax Dalmatian Toadflax Dyer's Woad Dyer's Woad
Leafy Spurge Leafy Spurge Medusahead Medusahead Purple Loosestrife Purple Loosestrife No Image Rush skeletonweed
Spotted Knapweed Spotted Knapweed Squarrose Knapweed Squarrose Knapweed Yellow Starthistle Yellow Starthistle Yellow Toadflax Yellow Toadflax

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Class 3 Weeds

Bermudagrass Bermudagrass Canada Thistle Canada Thistle Field Bindweed Field Bindweed Hoary Cress (small whitetop) Hoary Cress
Houndstongue Houndstongue No Image Jointed goatgrass Musk Thistle Musk Thistle Perennial Pepperweed (tall whitetop) Perennial Pepperweed
Johnsongrass Perennial sorghum ssp. (Johnsongrass) No Image Phragmites (Common reed) Poison Hemlock Poison Hemlock No Image Puncturevine (Goathead)
Quackgrass Quackgrass Russian Knapweed Russian Knapweed Scotch Thistle Scotch Thistle Saltcedar (Tamerix) Saltcedar

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Class 4 Weeds

No Image Cogongrass (Japanese blood grass) No Image Dame's rocket No Image Myrtle spurge No Image Russian-olive
No Image Scotch broom      

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State Noxious Weeds

Class 1A Weeds

Bermudagrass
Cynodon dactylon
Utah Class B

BACKGROUND: Bermudagrass probably came from Africa. It prefers warmer regions, but it is becoming established in cooler regions as well. It is posing a serious threat to crop production and turf management. It reproduces by seed, rhizomes, and lateral stolons taking root at any node.

DESCRIPTION: It is a low-growing and sod-forming perennial grass with stolon’s creeping along the ground and upright stems about 12 inches tall. Seed heads have three to seven terminal spikes each about two inches in length.

CONTROL: Biocontrol is not available. Herbicides can offer fair to good control. Tillage should not be used as a control. Contact your local state or county weed specialist for specific updated information.

bermudagrass seedlingsmature bermudagrass
bermudagrass seedhead

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Oxeye Daisy
Chrysanthemum leucanthemum L.
Utah Class A

BACKGROUND: This native of Europe survives in a wide range of environments. It is prevalent on poor soils, tolerates cold conditions and survives drought well. Often found in meadows, roadsides, waste areas, grasslands, or overgrazed pastures.

OTHER COMMON NAMES: Marguerite, moon-daisy

DESCRIPTION: This perennial, rhizomatous herb grows 1 to 3 feet tall. Leaves are lance-shaped with coarse teeth. Flowers range in diameter from 1 to 2.2 inches and blossoms usually appear from June to August. The plant has a disagreeable odor if crushed. Although not toxic, it can give milk an off-flavor if consumed by dairy cattle. It grows in patches and can spread vegetatively and by seed. Oxeye daisy is often confused with members of the Aster genus; however, the coarse teeth on the leaf margins differentiate it from asters.

CONTROL: Biocontrol is not available. Cultivation is effective. Maintaining a dense crop canopy is effective in stopping establishment. Several herbicides are effective in controlling oxeye daisy. Contact your state or county weed specialist for specific, updated information.

Oxeye Daisy adultOxeye Daisy flower
Oxeye Daisy leafOxeye Daisy root

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Poison Hemlock
Conium maculatum
Utah Class B

BACKGROUND: Poison hemlock is a European native growing six to ten feet tall. It is commonly found along waterways, roadsides, field edges, and tolerates poorly drained soils. It has been mistaken for parsley and wild carrot. All parts of the plant are toxic.

DESCRIPTION: This biennial has a large taproot. The stems have purple spots, especially at the bases. Leaves are finely divided, having a fern-like appearance. Leaf stems clasp the main stem. The tiny flowers are in umbrella-shaped clusters on the ends of individual stalks. Bloom is in late spring into early summer.

CONTROL: Biocontrol is available and offers fair to good control. Herbicides can offer excellent control when applied to actively growing plants between rosette and bloom stages. Contact your local state or county weed specialist for specific updated information.

poison hemlock rosettemature poison hemlock
poison hemlock flowerpoison hemlock leaf
poison hemlock spotted stempoison hemlock patch

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Black Henbane
Hyoscyamus niger
Utah Class A

Other common names: Hog’s bean

BACKGROUND: Black henbane is a native plant of Europe commonly found in waste areas, pastures, along rights-of-way, and fence lines. It is poisonous to both animals and humans. However, it has medical use in controlled circumstances.

DESCRIPTION: As either an annual or biennial, black henbane grows one to three feet tall. Leaves have pointed lobes and prominent veins. Off-white flowers with purple centers and veins are one to two inches wide bearing pineapple shaped fruit in leaf axils. Each fruit has five lobes and contains hundreds of tiny black seeds. Bloom occurs in late spring.

CONTROL: Biocontrol is not available. Herbicides can be very effective when applied during rosette to bloom stages. Digging can offer some control. Contact your local state or county weed specialist for specific updated information.

black henbane rosettemature black henbane
black henbane flowerblack henbane seedhead
black henbane taprootblack henbane patch

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Johnsongrass
Sorghum halepense
Utah Class A

BACKGROUND: Johnsongrass was introduced from the Mediterranean to the United States as a forage grass. However, when under frost or moisture stress it becomes toxic to livestock. It reproduces by seed and creeping lateral root systems. It thrives in rich soils and along waterways.

DESCRIPTION: Johnsongrass is a hardy perennial grass. It displays erect stems two to eight feet tall. Spreading roots send large fleshy rhizomes to the sides for wide distribution. Leaf blades are flat, up to one inch wide, with a prominent light midvein. Stems are stout with prominent nodes. Seed heads are reddish to purple.

CONTROL: Biocontrol is not available. Herbicides can offer good control. Contact your local state or county weed specialist for specific updated information.

Johnsongrass

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St. Johnswort
Hypericum perforatum
Utah Class A

Other common names: Klamath weed

BACKGROUND: St. Johnswort was introduced from Europe. It invades areas with sandy or gravelly soils. Reproduction is by seeds and short runners. It contains a substance that is toxic (but rarely fatal) to white-haired animals causing them to develop skin irritations and often lose weight when exposed to sunlight. It is also a key ingredient of some popular dietary supplements.

DESCRIPTION: This perennial grows one to three feet tall. Stems are rust colored and woody at the base. Leaves are characterized by prominent veins and transparent dots, visible when held up to light. The flowers are bright yellow with five petals.

CONTROL: Several biocontrol agents are available and can offer good to excellent control. Herbicides can offer good control when applied to actively growing plants between rosette and pre-bloom stages. Contact your local state or county weed specialist for specific updated information.

St. Johnswort rosetteSt. Johnswort adult
St. Johnswort flowerSt. Johnswort leaf
St. Johnswort patch

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Diffuse Knapweed
Centaurea diffusa
Utah Class A

BACKGROUND: Native to Eurasia, diffuse knapweed inhabits dry rangeland, roadsides, field edges, and waste areas. Knapweed’s release chemical substances into the soil that inhibit the growth of competing vegetation.

DESCRIPTION: It is an annual or a short-lived perennial averaging one to two feet tall. Leaves have finely divided lobes. Flowers are white to rose in color. Diffuse knapweed differs from squarrose knapweed in that toothed flower bracts are straight rather than arched outward. It blooms throughout summer.

CONTROL: Several biocontrol agents are available and provide fair to good control. Select herbicides can offer good to excellent control when applied from rosette to pre-bud stages. Tillage offers good control. Contact your local state or county weed specialist for specific updated information.

diffuse knapweed rosettemature diffuse knapweed
diffuse knapweed flowersdiffuse knapweed patch

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Squarrose Knapweed
Centaurea virgata
Utah Class B

BACKGROUND: Squarrose knapweed is a native plant of the eastern Mediterranean area. It is very competitive on rangelands. Knapweed releases a chemical substance reducing competing vegetation.

DESCRIPTION: This long-lived perennial grows 12 to 18 inches tall. The rosette and stems have deeply lobed leaves. Flowers are rose to pink. It is often confused with diffuse knapweed, but differs in that the toothed flower bracts are curved outward, and are not laterally toothed. Bloom occurs in early to mid-summer.

CONTROL: Several biocontrol agents are available. Herbicides offer good to excellent control. Contact your local state or county weed specialist for specific updated information.

squarrose knapweed rosettemature squarrose knapweed
squarrose knapweed flower

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Purple Loosestrife
Lythrum salicaria
Utah Class A

Other common names: Purple lythrum.

BACKGROUND: Purple loosestrife is a European plant probably introduced to the United States as an ornamental. It reproduces by both seed and creeping rootstocks. Infestations can impede water flow and replace beneficial plants and thus displace wildlife. It can be found in shallow marshy wetland areas and ditches.

DESCRIPTION: Purple loosestrife is a semi-aquatic perennial growing six to eight feet tall. There are five to seven petals on rose-purple flowers that appear in columns along the upper end of stems. Leaves are lance shaped with smooth margins up to five inches long. Bloom is in midsummer.

CONTROL: Biocontrol is limited in availability but control can be good to excellent. Herbicides with an aquatic label can offer fair to good control. Contact your local state or county weed specialist for specific updated information.

purple loosestrife rosettemature purple loosestrife
purple loosestrife flowerpurple loosestrife root
purple loosestrife patch

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Medusahead
Taeniatherum caput-medusae
Utah Class A

BACKGROUND: Medusahead was brought to the United States from Eurasia. It is extremely competitive completely displacing other desirable grass species. It spreads by seed commonly carried by wind, animals, clothing, and vehicles. Other common names: Medusahead rye

DESCRIPTION: Medusahead is an annual growing from six inches to two feet high. Leaf blades are about one-eighth inch wide. Awns of the seed head are long and become twisted as the seed matures. It is sometimes confused with foxtail barley or squirreltail, but is different in that the seed head doesn’t break apart completely as the seeds mature. Flowering and seed production take place in late spring and early summer.

CONTROL: Biocontrol is not available. A combination of burning, herbicide, and reseeding offers the best control. For the best results, this should be done in fall through early winter. Contact your local state or county weed specialist for specific updated information.

medusahead seedlingmature medusahead
medusahead seedheadmedusahead patch

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Yellow Starthistle
Centaurea solstitialis
Utah Class A

BACKGROUND: Yellow starthistle was introduced from Europe. It grows well on dry sites in rangeland, roadsides, and waste areas. It can cause “Chewing disease” in horses that consume it.

DESCRIPTION: Yellow starthistle is a two to three foot tall winter annual with blue-green coloration. Rosette leaves are deeply lobed and could be confused with dandelion. Stems are sparsely leaved and heavily ridged. Flowers are yellow. Cream-colored thorns, one-quarter to three-quarter inches long, protrude from the flowering heads. Bloom is in early summer.

CONTROL: Several biocontrol agents have been tested but availability is limited. Select herbicides offer fair to good control when applied between rosette and bloom stages. Tillage is effective. Contact your local state or county weed specialist for specific updated information.

yellow starthistle rosettemature yellow starthistle
yellow starthistle floweryellow starthistle stem wings
yellow starthistle rootsyellow starthistle patch

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Scotch Thistle
Onopordum acanthium
Utah Class B

Other common names: Cotton thistle

BACKGROUND: Scotch thistle is native to Europe and eastern Asia. It grows well in waste areas, pastures, range land, and along canal and stream banks.

DESCRIPTION: This biennial plant commonly grows three to eight feet tall, but it may grow as high as 12 feet. Rosettes may be four feet wide. Large spiny leaves up to two feet long and one foot wide are covered with dense hair, giving a grayish blue-green coloration. The flowers are violet to reddish with spine tipped bracts, blooming in mid summer.

CONTROL: Biocontrol research is currently being conducted. Herbicides can offer good to excellent control when applied between rosette and pre-bud stages. Contact your local state or county weed specialist for specific updated information.

Scotch thistle rosettemature Scotch thistle
Scotch thistle flowerScotch thistle stem wings
Scotch thistle patch

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Dalmatian Toadflax
Linaria genistifolia
Utah Class B

BACKGROUND: Dalmatian toadflax was brought to the United States from Europe, probably for ornamental purposes. It prefers rangeland and roadside habitat with sandy soils. It is very aggressive and hard to control due to deep roots and a thick waxy leaf cuticle. It reproduces by seed and rootstock.

DESCRIPTION: This perennial weed grows from two to nearly four feet tall. Multiple stems may come from the base. Blue-green leaves line the stem in alternate fashion. Leaves are wedge shaped, have a thick waxy cuticle, and partially clasp the stem. Flowers are yellow and may have white highlights, and have long tails appearing similar to snap dragon flowers. Bloom is in late spring into summer. Fruits are two celled berry-like capsules containing many seeds.

CONTROL: Biocontrol is available and offers fair control. Select herbicides can offer good control when applied from spring through fall. Contact your local state or county weed specialist for specific updated information.

dalmatian toadflax rosettemature dalmatian toadflax
dalmatian toadflax flowerdalmatian toadflax patch

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Yellow Toadflax
Linaria vulgaris
Utah Class A

Other common names: Butter and eggs, toadflax

BACKGROUND: Yellow toadflax came from Eurasia. It is an aggressive invader of rangeland, roadsides, field edges, and waste areas. An extensive root system makes this weed difficult to control. It reproduces by seeds and roots.

DESCRIPTION: This perennial weed grows to two feet tall. Leaves are two and one-half inches in length, narrow, and pointed. Flowers are about one inch long, yellow with an orange throat, and have long tails. They look similar to snap dragon flowers. Bloom is in late spring into summer. Fruits are small one-fourth inch, two celled berry-like capsules containing many seeds.

CONTROL: A few biocontrol agents are available and offer fair control. Herbicides can offer good control. Contact your local state or county weed specialist for specific updated information.

Yellow Toadflax rosetteYellow Toadflax adult
Yellow Toadflax flowerYellow Toadflax patch

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Dyer's Woad
Isatis tinctoria
Utah Class B

Other common names: Woad

BACKGROUND: Dyer's woad was introduced from Europe for pr0oduction of textile dyes. It thrives in waste areas, gravel pits, road sides, pastures, field edges, and disturbed soils.

DESCRIPTION: Dyer’s woad may be a winter annual, biennial, or a short-lived perennial. Heights of one to four feet are common. A thick tap root may penetrate to five feet deep. Leaves are blue-green with a whitish midrib. The bright yellow flowers bloom and are highly visible in late spring. Club shaped seed pods each produce a single seed. As the fruits mature they turn from green to dark brown or nearly black.

CONTROL: Biocontrol rust fungus is naturally wide spread and other agents are currently undergoing research. Rust infected plants will have yellowish puckered leaves with dark spots on the underside. Herbicides can offer good to excellent control when applied to rosettes in spring and fall and during pre-bloom. Digging offers good control. Contact your local state or county weed specialist for specific updated information.

dyer's woad rosettemature dyer's woad
dyer's woad flowerdyer's woad new green seed
dyer's woad mature black seeddyer's woad patch

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Class 1B Weeds

Hoary Cress
Cardaria draba
Utah Class B

Other common names: Small whitetop, whitetop

BACKGROUND: This plant originated in Europe. It reproduces by root segments and seed. It is commonly found on disturbed sites along road ways, field edges, and excavations. It is also a widespread weed of grain fields, cultivated fields, meadows and grows particularly well on somewhat salinic soils.

DESCRIPTION: Hoary cress is a perennial plant commonly one to two feet tall with creeping rootstocks. Leaves are finely toothed. Upper leaves clasp the stem. Bloom is in late spring with clusters of white flowers, each flower containing four petals. Seed pods are heart shaped and contain two brownish seeds.

CONTROL: Biocontrol research is in the early stages. Select herbicides can offer fair to good control when applied from rosette to early bloom stages. Contact your local state or county weed specialist for specific updated information.

hoary cress rosettemature hoary cresshoary cress flowerhoary cress seedhoary cress patch

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Houndstongue
Cynoglossum officinale
Utah Class C

BACKGROUND: Houndstongue is a native of Europe. It thrives in disturbed soils along roadsides, trails, in pastures, and rangelands. Because of the bur-like seed, it spreads widely along travel corridors as a passenger on clothing or animal fur. It is toxic to livestock.

DESCRIPTION: Houndstongue is a one to four foot tall biennial. Basal leaves are about three inches wide with a hairy surface. Upper leaves are narrower, about one inch wide and have a curled appearance, and partially clasp the stem. Small reddish purple flowers form in the upper portions of the plant along stems borne in leaf axils. Each flower produces four green bur-like fruits that turn brown as they mature. Bloom is in early summer.

CONTROL: Biocontrol is not available. Herbicides can offer good to excellent control when applied between the rosette and bloom stages. Digging before seed development can offer good control. Contact your local state or county weed specialist for specific updated information.

houndstongue rosettemature houndstongue
houndstongue flowerhoundstongue seed
houndstongue seed on a shoelacehoundstongue patch

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Spotted Knapweed
Centaurea maculosa
Utah Class A

BACKGROUND: Originally found in Eurasia, spotted knapweed infests rangeland, pastures, roadsides, or any disturbed soils. Knapweed’s release chemical substances into the soil that inhibit the growth of competing vegetation.

DESCRIPTION: Spotted knapweed is a short-lived perennial one to three feet tall. The rosette leaves are deeply lobed and may be six inches in length. The stems are moderately leaved. Flowers are typically pink with spots on the flower bracts. Bloom is in early summer.

CONTROL: Several biocontrol agents are available and offer fair to good control. Select herbicides can offer good to excellent control when applied between rosette and killing frost. Contact your local state or county weed specialist for specific updated information.

spotted knapweed rosettemature spotted knapweed
spotted knapweed flowerspotted knapweed patch

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Leafy Spurge
Euphorbia esula
Utah Class A

BACKGROUND: A native plant of Eurasia, leafy spurge is an aggressive invader of pastures, rangeland, stream banks, and waste areas. It reproduces by seed and rootstock. It is toxic to cattle and may result in their death.

DESCRIPTION: This perennial plant grows up to three feet tall. The leaves are narrow, one to four inches long. In late spring, yellow-green flower bracts appear. Seeds are contained in a three-celled capsule, one seed per cell. When dry, capsules can shoot seeds up to 15 feet from parent plant. Stems exude a milky fluid when damaged. An extensive root system, up to 20 feet long and more than 14 feet deep, with multiple shoot-producing buds, makes this plant very difficult to control.

CONTROL: Biocontrol is extensive and control is fair to excellent. Herbicides can offer fair to good control especially when combined with biocontrol. Apply herbicides from spring to the killing frost. Contact your local state or county weed specialist for specific updated information.

young leafy spurgemature leafy spurge
leafy spurge flowerleafy spurge milky latex sap
leafy spurge patch

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Class 2 Weeds

Field Bindweed
Convolvulus arvensis
Utah Class C

BACKGROUND: This European native reproduces from both seed and rootstock. Seeds may remain viable in the soil for up to 50 years. It grows in fields, pastures, gardens, road sides, and many other areas. It may be found in areas up to 10,000 feet in elevation. Other common names: Morningglory, bindweed, wild morning-glory

DESCRIPTION: Field bindweed is a perennial with stems up to six feet long growing prostrate, or it may climb nearby vegetation. The root system may grow to a depth of ten feet or more. Arrow-shaped leaves are up to two inches long. Flowers are funnel shaped, white to pink, and one inch wide. Bloom is from June through September.

CONTROL: Biocontrol is not available. Several herbicides offer good control when applied from late spring to the killing frost. Contact your local state or county weed specialist for specific updated information.

field bindweed rosettemature field bindweed
field bindweed flowerfield bindweed patch

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Russian Knapweed
Centaurea repens
Utah Class B

BACKGROUND: Russian knapweed is native to Eurasia. It infests rangelands, field edges, pasture, roadsides, and other disturbed soils. Knapweed’s release chemical substances into the soil that inhibit the growth of competing vegetation. It can cause “Chewing disease” in horses that consume it.

DESCRIPTION: A perennial, Russian knapweed grows two to three feet tall. Roots may go eight feet deep or more. Basal leaves are lobed and are two to four inches in length. It has pinkish flowers. Flower bracts have membranous cream-colored tips. Bloom is early summer through late summer.

CONTROL: Biocontrol is available, but limited. Select herbicides can offer good to excellent control when applied between pre-bloom to the killing frost. Contact your local state or county weed specialist for specific updated information.

Russian knapweed rosettemature Russian knapweed
Russian knapweed flowerRussian knapweed bracts
Russian knapweed tap rootRussian knapweed patch

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Perennial Pepperweed
Lepidium latifolium
Utah Class B

Other common names: Tall whitetop, broad-leaved peppergrass

BACKGROUND: Native to southern Europe and western Asia, perennial pepperweed is commonly found in wet drainage areas of waste areas, ditches, roadsides, and crop lands.

DESCRIPTION: Perennial pepperweed grows from one to six feet high. It has spreading lateral rootstocks. Leaves have smooth to lightly toothed margins. Stems and leaves are waxy. White flowers form dense clusters at the end of branches. Flowering takes place from summer into early fall.

CONTROL: Biocontrol research is in early stages. Select herbicides can offer fair to excellent control when applied to actively growing plants up to full bloom. Contact your local state or county weed specialist for specific updated information.

perennial pepperweed rosettemature perennial pepperweed
perennial pepperweed flowerperennial pepperweed seedhead
perennial pepperweed taprootperennial pepperweed patch

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Quackgrass
Elytrigia repens
Utah Class C

BACKGROUND: Originally found in the Mediterranean area, quackgrass infests crops, rangeland, pasture, and lawns. It adapts well to moist soils in cool temperate climates. It reproduces by seed and rhizomes. These rhizomes can penetrate hardened soils and even roots of other plants.

DESCRIPTION: This perennial grass usually grows one to three feet tall. Rhizomes are creamy colored and pointed. Leaf blades are up to a half inch wide. Near the tip of the leaves a band-like constriction may be present. Seed heads are three to four inches long and narrow.

CONTROL: Biocontrol is not available. Herbicides can offer good control when applied from early spring to winter. Contact your local state or county weed specialist for specific updated information.

mature quackgrassquackgrass seed
quackgrass leaf constriction and seedheadquackgrass patch

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Saltcedar
Tamarix ramosissima
Utah Class C

Other common names: Tamarisk, tamarik, tamarix

BACKGROUND: Saltcedar was introduced from Eurasia and is found throughout the United States. It is widely used as an ornamental. It commonly infests lake and stream banks as well as pastures and rangeland. Large plants can transpire 200 gallons of water per plant per day drying up ponds and streams.

DESCRIPTION: This perennial plant grows five to twenty feet tall. Stems are reddish-brown. Leaves are small and scale-like. Branches are long and slender. White to pink flowers have five petals and are borne in finger-like clusters. The root system is extensive. Saltcedar may exhibit either deciduous or evergreen traits.

CONTROL: Biocontrol is available but is still undergoing testing. Select herbicides can offer excellent control when applied in late summer through early fall. Contact your local state or county weed specialist for specific updated information.

young saltcedarmature saltcedar
saltcedar flowersaltcedar patch

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Canada Thistle
Cirsium arvense
Utah Class C

Other common names: California thistle, field thistle

BACKGROUND: A native to southeastern Eurasia, Canada thistle reproduces by seeds and rootstock. It is adaptable to a diverse range of habitats.

DESCRIPTION: Canada thistle is a perennial plant usually from one to four feet tall, in sparse to extremely dense colonies. Leaves have spiny tipped lobes. Flowerheads are softly spined, light pink to purple, and are typically three-quarter inch in diameter. Bloom occurs in July and August.

CONTROL: Several biocontrol agents are available offering fair control. Herbicides can offer good control when applied to actively growing plants from spring to fall. As with most creeping perennials, digging or tillage is generally not effective. Contact your local state or county weed specialist for specific updated information.

Canada thistle rosettemature Canada thistle
Canada thistle flowerCanada thistle patch

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Musk Thistle
Carduus nutans
Utah Class B

Other common names: Nodding thistle

BACKGROUND: Native to southern Europe and western Asia, musk thistle thrives in pastures and range lands, in waste areas, stream banks, and road sides.

DESCRIPTION: Musk thistle is a biennial or winter annual. Four to six foot tall plants are common. Deeply lobed leaves are distinguished by a dark green blade with a prominent light green midrib. Flowers may be violet, purple, or rose colored. Flowers are typically “nodding” or bent over. Ends of stems supporting flowers are often nearly leafless. Bloom is in June and July.

CONTROL: Several biocontrol agents are available and offer good control. Herbicides can offer good to excellent control when applied between rosette and pre-bud stages. Mechanical means can be used for control by chopping the plant off at the ground. Contact your local state or county weed specialist for specific updated information.

musk thistle rosettemature musk thistle
musk thistle flowermusk thistle patch
musk thistle patch

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Class 3 Weeds

Class 4 Weeds

County Noxious Weeds

Class A Weeds

Common Teasel
Dipsacus fullonum

BACKGROUND: Native to Europe, teasel is spreading rapidly throughout much the United States.This biennial plant typically grows to 6 feet tall. It commonly grows in moist areas in pastures, along canals, streams, and in disturbed sites. Upper stems and heads are often used in winter flower arrangements.

DESCRIPTION: Teasel sprouts a single stem that branches about half way up. Stems are spiny. Leaves are conspicuously veined and have stiff prickles on the lower midrib. Purple flowers are borne in a spiny., cone-like head from July to August.

CONTROL: Herbicides offer good control. Contact your local state or county weed specialist for specific updated information.

common teasel rosettecommon teasel flower
common teasel seedheadcommon teasel spiney stem
common teasel patchcommon teasel patch

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Class B Weeds

Puncturevine
Tribulus terrestris

Other common names: Goathead, bullhead, Mexican sandbur, Texas sandbur

BACKGROUND: A native to Europe, puncturevine is common along roadsides, in farm areas, pastures, cultivated fields, and waste areas. Hard spiny seeds damage bike tires and thin walled car tires, and injure livestock.

DESCRIPTION: Puncturevine is an annual, spreading its multiple stems prostrate along the ground. Stems may be up to five feet long. Leaves are compound pinnate with four to eight pairs of leaflets. Each leaflet is less than half an inch long. Small yellow flowers have five petals and are about one-third inch wide. The flowers produce hard, spiny, five-lobed fruits. At maturity the fruit breaks into tack-like structures each containing two to four seeds. Bloom is in late spring and early summer.

CONTROL: Biocontrol is available. Herbicides can offer good to excellent control when applied in spring. Contact your local state or county weed specialist for specific updated information.

puncturevine rosettemature puncturevine
puncturevine flowerpuncturevine seedhead
individule puncturevine seed capsulespuncturevine tap root
puncturevine in roadwaypuncturevine patch

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Class 3 Weeds

Russian-Olive
Elaeagnus angustifolia

BACKGROUND: This tree, from Europe, is often used as an ornamental. Fruits can be a valuable food for wildlife. It grows well in meadows, pastures, and along waterways. Reproduction is from seed and rootstock. Russian-olive is very difficult to control. Thick stands can develop if left unchecked.

DESCRIPTION: Russian-olive trees grow up to 25 feet in height. From a distance they have a light gray-green appearance due to tiny scales on the leaf surfaces. The trunk and branches have many one to two-inch thorns. Leaves are narrow and two to three inches in length. Inconspicuous yellow flowers are found in clusters which later produce tan or silver colored olive-like fruits about half an inch in length.

CONTROL: Biocontrol is not available. Herbicides can offer fair to good control when applied in late summer through early fall. Contact your local state or county weed specialist for specific updated information.

mature Russian-oliveRussian-olive flower
Russian-olive seedRussian-olive thorn
Russian-olive patch

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Invading Noxious Weeds

Buffalobur
Solanum rostratum

BACKGROUND: Native to the United States, buffalobur infests corals, gardens, pastures, and waste areas. It grows in most soil types but prefers sandy soils. It is drought resistant making it very competitive with other less drought tolerant species.

DESCRIPTION: This annual grows one to two feet tall with spines on stems, leaves, and seed heads. Leaves are heavily lobed and have prominent veins. Yellow, five-lobed flowers adorn buffalobur throughout the summer.

CONTROL: Biocontrol is not available. Herbicides can offer excellent control. Diligent digging of this weed can offer good control. Contact your local state or county weed specialist for specific updated information.

buffalobur rosettemature buffalobur
buffalobur flowerbuffalobur seedheads
buffalobur spinesbuffalobur patch

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Common Burdock
Arctium minus

BACKGROUND: Common burdock is native to Europe. It is commonly found along ditch banks, roadsides, game trails, hiking trails, and pastures. It tolerates both shade and full sun. Burs often become attached to clothing and animal hair and are distributed to new areas.

DESCRIPTION: As a biennial, common burdock produces a large rosette the first year which can be two to three feet across. The second year a multi-branched stem grows three to ten feet tall. Flowers are pink to purple borne in bur-like structures.

CONTROL: Biocontrol is not available. Select herbicides can offer good to excellent control when applied between rosette and bloom stages. Contact your local state or county weed specialist for specific updated information.

common burdock rosettemature common burdock
common burdock flowercommon burdock seed
common burdock patch

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Halogeton
Halogeton glomeratus

BACKGROUND: This annual weed, native to Asia, ranges in height from 3 to over 18 inches. It is well suited to alkaline soils and semi-arid environments. It is not highly competitive but it readily invades disturbed or overgrazed lands. It is commonly found along roadsides, sheep trails and where cattle congregate. It is especially toxic to sheep and may also affect cattle.

DESCRIPTION: Plants are blue-green with red stems. Main branches begin growth by spreading horizontally then becoming erect. Leaves are fleshy and cylindrical tipped with a delicate spine. Inconspicuous, greenish flowers form in leaf axils along the upper half of stems and bloom in late summer.

CONTROL: Herbicides can offer good control when applied in early stages of growth. Contact your local state or county weed specialist for specific updated information.

young halogetonmature halogeton
halogeton leafhalogeton root
halogeton patch

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Myrtle Spurge
Euphorbia myrsinites

Other common names: Donkey-tail and creeping spurge

BACKGROUND:This plant is native to the Mediterranean region and was introduced to the United States as an ornamental. It grows well in dry, well-drained soils in part to full sun. The latex (sap) is toxic and may cause severe dermatitis, burns and/or blisters in sensitive people. Always wear hand and eye protection when handling this plant.

DESCRIPTION: This perennial produces fleshy, blue-green leaves that form tight spirals around spreading, prostrate stems. Flowers appear in spring as bright yellow-green bracts surrounding inconspicuous flowers. Stems branch out from a central taproot, growing up to 18" long. Plants are generally from 6 to 12 inches tall. A milky sap (latex) oozes from any part of the plant that is broken. Reproduction is primarily from seed, however, roots broken by cultivation may also form new plants.

CONTROL: Herbicides can offer good to excellent control of this weed. Contact your local state or county weed specialist for specific updated information.

mature myrtle spurgeyoung myrtle spurge
myrtle spurge leafmyrtle spurge milky latex sap
myrtle spurge patch

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Common Tansy
Tanacetum vulgare

Other common names: Garden tansy

BACKGROUND: This native perennial of Europe was established in the United States as an ornamental or for a medicinal herb. it is often found along roadsides, stream banks, in waste areas, and pastures. Common tansy is often mistaken for tansy ragwort.

DESCRIPTION: Common tansy may be from 1 1/2 to 6 feet tall. Leaves are deeply divided with toothed segments. Small 1/4 to 1/2 inch yellow flowers form in clusters at the ends of stems. Seeds are yellowish-brown with short 5-toothed crown. Reproduction is from seed and rootstock.

CONTROL: Several herbicides are available for control. Contact your local state or county weed specialist for specific updated information.

common tansy flower

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Bull Thistle
Cirsium vulgare

BACKGROUND: Bull thistle is native to Europe. It now infests much of North America. It is often found in pastures, fields, roadsides, and disturbed sites. It is most common in lower, heavier soils, and moist areas.

DESCRIPTION: This biennial can grow from two to five feet tall supported by a short fleshy taproot. Leaves are highly lobed, prickly on upper surface, and cottony underneath. Flowers are one and one-half to two inches wide and are pinkish-purple. Seeds are topped by a circle of plume-like white hairs.

CONTROL: Biocontrol is available. Herbicides can offer excellent control when applied between rosette and bloom stages. Contact your local state or county weed specialist for specific updated information.

bull thistle rosettemature bull thistle
bull thistle flowerbull thistle seed
bull thistle patchbull thistle patch

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Velvetleaf
Abutilon theophrasti

BACKGROUND: Velvetleaf was introduced from Asia. It is commonly found in rich soils in and around cultivated fields, gardens, and waste areas, causing problems for agriculture. This weed is very difficult to eradicate because the seeds may remain viable for more than 50 years. Before the flower’s bloom it may be confused with common sunflowers.

DESCRIPTION: Velvetleaf is an annual growing from two to seven feet in height. The entire plant, from the ground up, is covered in fine hairs giving it a very soft texture. Large heart-shaped leaves are five inches or more across. Flowers have five petals and are yellow-orange. The flowers emerge from the leaf axils and bloom in early summer.

CONTROL: Biocontrol is not available. Herbicides can offer excellent control. Tillage can suppress this weed. Contact your local state or county weed specialist for specific updated information.

velvetleaf rosettemature velvetleaf
velvetleaf flowervelvetleaf flower
velvetleaf seedheadvelvetleaf patch

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Western Waterhemlock
Cicuta douglasii

BACKGROUND: This perennial is native to the Western United States. It is considered one of the most poisonous plants in North America to both animals and humans. It is often mistaken for water-parsnip and other edible members of the parsley family. It occurs along streams and canals.

DESCRIPTION: Waterhemlock grows 3 to 7 feet tall. pinnate shaped leaves leaves are lightly serrated. White flowers grow in clusters at the tips of stems. Stems are hollow. The taproot is horizontally divided.

CONTROL: Herbicides can offer good control. Contact your local state or county weed specialist for specific updated information.

mature western waterhemlockwestern waterhemlock flower
western waterhemlock seedwestern waterhemlock hollow stem
western waterhemlock leafwestern waterhemlock patch

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