Saltcedar is native to Eurasia but was introduced to North American in the early 1800’s as an ornamental and also for erosion control.  It was quick to escape cultivation and has since been spreading rapidly.  This attractive shrub has characteristics similar to an evergreen but looses its leaves in the colder months and is therefore considered deciduous.  Saltcedars readily establish along waterways, streams, canals, banks, drainage areas, and anywhere that the soils are exposed to an extended period of moisture.

Saltcedar has become well established throughout the southwestern United States and Mexico.  There are also extensive infestations in many of the northern states and small but well-established stands in Oregon, Idaho, Montana, Wyoming, South Dakota, and North Dakota.  In most western Montana counties, these shrubs are found as ornamental in landscaped yards.

Concerns

This long-lived shrub (50-100 years) can spread by both vegetative re-growth and seeds.  Each flowering shrub produces around 600,000 seeds.  Not only are they long lived and have great reproductive capabilities, but they also grow extremely rapidly.  Most of these shrubs can flower the same year they germinate.  They exclude native vegetation by exuding salts above and below ground.  This creates a saline crust, which inhibits other plants from growing in close proximity.  The other main concern with Saltcedar is its consumption of large quantities of water.  One shrub can consume up to 250 gallons of water in 1 day.  This can result in lowering the ground water and drying up springs and marshes, which in turn lessens the amount of water available in riparian areas.  Saltcedar’s dense roots also slow down river flow, which increases deposition of sediments along the river bank.  This widens the riparian zones causing a severe reduction in streamflow or rechanneling, which creates more habitat for Saltcedar to colonize.

Identification

This shrub can reach heights of up to 25 feet and has dense branches that often make it many feet wide.  The narrow leaves of a Saltcedar resemble those of a juniper but they fall off in the colder months unlike junipers.  This shrub is also known as a smoke tree because of it beautiful plumes of deep pink to white flowers that crowd the tips of the branches.  The bark of a Saltcedar is reddish-brown, while the wood is soft and white.  The smooth bark becomes furrowed with age.

What can you do?

Saltcedar is very difficult to control.  A combination of methods is the most effective means of control.  Cutting the stump and immediately applying herbicide has proved to be successful.  The herbicide has to be applied within 1 minute of cutting the shrub or it will not penetrate into the stump.  If you have a Saltcedar or you know where one is please contact your local weed district.  We will be happy to help in the proper control of these highly invasive shrubs.

Visit the MWCA Weed ID pages for additional information and pictures of saltcedar.

This series of articles was developed by Ravalli County.  If you would like to use these articles please contact Ravalli County Weed District Weed Coordinator at (406) 777-5842.

Houndstongue was introduced into the U.S. in the 1900’s from Eurasia as a cereal contaminant.  It is also known as sheep’s lice, dog’s bur, beggar’s lice, woolmat, and glovewort.  The seed of houndstongue has been said to be the inspiration for Velcro.

Concerns

In Montana, houndstongue infests an estimated 36,000 acres.  Where it is established it will displaces native vegetation and cause problems on pasturelands. The taproot of houndstongue grows deep into the soil and is very efficient at capturing soil nutrients and water reducing what is available for beneficial native grasses and forbs.

It has an uncanny ability to disperse its seeds. The seeds of houndstongue are covered with Velcro-like barbs that attach to clothing, hair, fur, and feathers.  They can be transported long distances into new areas by animals, people, vehicles, etc.  Each plant can produce up to 2000 seeds that can remain viable on the parent plant for 2-3 years.

Houndstongue is not generally palatable to grazing animals but on occasion when they are in a confined area with nothing else to eat they will graze on it.  This can be a problem because houndtongue contains poisonous chemicals that in high doses can kill an animal.  The chemical found in houndstongue is pyrroli-zidine alkaloids, which will cause liver damage in horses and cattle but not in sheep.

Identification

Houndstongue is a member of the Boraginaceae (Borage) family.  It is a biennial, meaning that its lifecycle is completed in two years.  The first year a rosette will emerge and the second year flowering stocks will grow up to 4 feet tall.  The rosette and flowering stock leaves are oblong and are covered in soft white hairs.  The deep vienation on the leaves is said to resemble a hound’s tongue, which lead to its common name.  The flowers range from red to a deep burgundy.  Each flower produces a seed cluster containing 3-4 teardrop-shaped fruits or nutlets.  It begins flowering in mid-June.

What can you do?

The most important management tool for houndstoungue is prevention. It is important to not let this weed spread and establish in new areas. You can help stop the spread of this weed by: containing infestations, limiting weed seed dispersal, identifying and eradicating new infestations, minimizing soil disturbance, planting competitive grasses, and properly grazing infested areas.

Hand-pulling this weed is beneficial, as long as at least 2 inches of the root crown is removed.  After removing houndstongue bag or burn the weed in order not to spread the seeds. An effective biological control has not yet been release in Montana. There are also herbicides that work well on houndstongue.  For more information on houndstongue or any other weed, call your local county weed district.

Visit the MWCA Weed ID pages for additional information and pictures of Houndstongue.

This series of articles was developed by Ravalli County.  If you would like to use these articles please contact Ravalli County Weed District Weed Coordinator at (406) 777-5842.

Canada thistle is native to Europe and northern Asia and was brought to the United States in the early 1600’s as a contaminant in grain.  By the 1950’s, Canada thistle was declared a noxious weed in 43 states. Canada thistle was partially responsible for the existence of noxious weed laws.  In the 1900’s, the Canada thistle law was enacted.  It gave a person the right to trespass onto someone else’s property in the name of Canada thistle eradication.

Concerns

Canada thistle is an aggressive competitor.  This weed has a long creeping root system that will steal precious nutrients and water from native vegetation.  The height of this weed also shades the ground below making it very difficult for grasses and forbs to grow.  Canada thistle will form colonies in areas that have been recently disturbed, abandoned fields, ditches, and prairies.

The presence of this weed will change the plant structure of communities and decrease biodiversity.  Canada thistle can be a huge problem on agricultural land due to the fact that it is an alternate host for some insects and pathogens that are known to attack certain crops.  It is also difficult and expensive to control.

Identification

This thistle is unique because it is a perennial, whereas most thistles are biennial, this also makes it harder to control.  Canada thistle can grow from 1 to 4 feet tall.  The leaves of this thistle are attached alternately along the stem; they are lance-shaped, lobed and spine-tipped.  The leaves get gradually smaller as they progress up the stem.  The stem is branched and sometimes hairy, but it lacks spines.

The flowers of the Canada thistle are usually purple and sometimes white.  They are ½ to ¾ inch in diameter and grow in clusters at the end of stems.  Each plant can produce up to 5,300 seeds that are easily distributed by the wind due to the tufts of hair attached to them.  The seeds remain viable in the soil for up to 20 years.

What can you do?

Stop small infestations before they take over.  Burning and mowing are somewhat effective because they allow native and desirable plant to compete with this weed.  These two techniques must be repeated for many years to achieve real success because of the longevity of the seeds in the soil and the weeds ability to sprout from broken roots.  Hand pulling and cultivation generally are ineffective and time consuming.  These two methods will not remove all of the roots and plant will re-sprout from the remaining roots.  There are herbicides that are effective.  If you have any further questions regarding this weed or other weeds on your property call your local weed district.

Visit the MWCA Weed ID pages for additional information and pictures of Canada Thistle.

This series of articles was developed by Ravalli County.  If you would like to use these articles please contact Ravalli County Weed District Weed Coordinator at (406) 777-5842.

Melissa Graves, Plant Identification Diagnostician from Montana State University’s Schutter Diagnostic Lab, gave a full description of the invasive aquatic plant that occurs in ponds, lakes, and slower moving streams or rivers.

“Curly-leaf pondweed prefers shallow water depths with a silty, high-nutrient bottom. It is distinguished from native pondweed species by its growth habit and distinctive leaf edges. Unlike native pondweeds, it actively grows in winter, with new plants emerging in spring. The leaves have wavy edges resembling lasagna noodles. They are about one to three inches long, narrow, reddish in color, and translucent, with flattened stems visible through the leaves.”

Read the complete article from MSU News Service here.

Visit the MWCA curly leaf pondweed identification page.

Leafy Spurge was introduced as an ornamental into the United States in the 1800’s.  Presently, leafy spurge covers over 3 million acres in 29 states.  It is having major economic and ecological impacts on many western states.  These impacts are related to its affect on grazing, wildlife habitat, wildlife related recreation, native plant populations, and ecosystem biodiversity.

Concerns

Leafy spurge is extremely aggressive and can out-compete native vegetation creating monocultures.  The milky sap emitted from the stem of leafy spurge is poisonous to humans, horses, and cattle.  There are cases where this sap has killed livestock and resulted in blindness in humans.  Like livestock, wildlife also avoids grazing spruge.  The abundance of leafy spurge in areas historically grazed by wildlife has caused them to migrate into areas they have not before inhabited.

Leafy spurge is having an enormous economic impact on the western states.  Montana, North and South Dakota, and Wyoming together spend approximately $144 million per year on leafy spurge control.  Land that has been invaded with leafy spurge has a decreased market value because of the plants detrimental ecological effects, as well as, the costs associated with control.

Identification

Leafy spurge has small, inconspicuous green flowers that are surrounded by a pair of yellow-green heart shaped leaves.  These leaves are often mistaken for the flower itself. This plant can grow up to 3 feet tall and when the stem is broken milky white sap seeps from it.  The leaves that attach to the stem also seep white sap when damaged.  These leaves are long and arranged alternately along the stem.  The taproot of leafy spurge can be up to 30 feet deep.  The seed head on this plant explodes when it is dry, sending the seed up to 15 feet from the mother plant.

What can you do?

Leafy spurge is an aggressive competitor and it takes aggressive management to gain control of infestations.  The most successful means of control of leafy spurge have been an intergraded weed management plan that utilizes a combination of methods.  There are five methods of controlling leafy spurge, they include:  prevention, hand-pulling, biological, revegetation, grazing, and chemical.  Prevent infestations by using weed and weed seed free hay, mulch, and gravel.  It is also important to prevent the transportation of seeds and root particles on vehicles or clothing.  Eradicate small outbreaks as soon as possible.  Hand pulling spurge is not the most efficient method, but it can be effective on plants that are in their first year of growth.  There are biological controls that have been found to be effective in Montana.  They are the flea beetles (Apthona) and root/stem boring beetles (Oberea erythrocephala).  Sheep and goat grazing can also be a useful tool when timed correctly and supervised by a knowledgeable herder.  Revegetation with competitive plants is always important with any weed control program.  All leafy spurge outbreaks take patience and attentiveness to overcome.  Have any questions?  Call your local county weed district.

Visit the MWCA Weed ID pages for additional information and pictures of leafy spurge.

This series of articles was developed by Ravalli County.  If you would like to use these articles please contact Ravalli County Weed District Weed Coordinator at (406) 777-5842.

Oxeye Daisy is native to Europe and was introduced to the United States as a contaminant in seed and as an ornamental.  It was quick to escape cultivation and has since been a common weed.  It was not only grown for its beauty but also for its natural remedies associated with whooping cough, asthma, and other coughs.  The leaves can also be eaten in salads.

Oxeye Daisy is found in most states but is less common in the south.  It is listed as a noxious weed in Washington, Wyoming, and Montana.  It was first reported in Montana in 1890 and its distribution across the state is still increasing.

Concerns

Cattle avoid eating oxeye daisy and therefore it has become widespread throughout pasturelands.  Stands of this plant can become very dense and displace native vegetation.  It has the ability to form dense stands because a single plant can produce up to 26,000 seeds per year and each one of those seeds can remain viable in the soil for up to 40 years.  This plant also has the ability to spread by roots.

Identification

Oxeye daisy is a perennial plant that looks like a typical daisy, with 20-30 white petals that radiate out from a yellow center.  This plant can grow to be 1-3 feet tall.  The leaves progressively get smaller in size the higher up the stem they are.  The basal leaves and the lower stem leaves are lance shaped with toothed margins and the leaves on the upper stem are alternately arranged, narrow, and often clasp the stem.  Scentless chamomile and shasta daisy look very similar to oxeye daisy but scentless chamomile is an annual and shasta daisy grows to be 6-12 inches taller than oxeye daisy.

What can you do?

Proper management is often neglected because oxeye daisy is a showy, attractive plant.  It is often included in wildflower seed mixes so consumers need to be sure to read labels.  Mowing can be beneficial if it is done as soon as flowers appear which will reduce seed production.  If mowing is the only means of control it needs to be repeated throughout the growing season because each mowing many stimulate shoot growth and subsequent flowerings will occur.  This plant can be dug up but all of the root system must be removed.  This process will have to be continued for several years because of the seed viability.   Herbicides can be a very useful tool in the fight against oxeye daisy if the proper chemical is used at the proper rate.  Horses, sheep, and goats will readily graze on daisy so they can also play a part in controlling this weed.  If you have any questions about Oxeye daisy or any other noxious weed please call your local weed district.

Visit the MWCA Weed ID pages for additional information and pictures of oxeye daisy.

This series of articles was developed by Ravalli County.  If you would like to use these articles please contact Ravalli County Weed District Weed Coordinator at (406) 777-5842.

Whitetop, also known as hoary cress was first identified in Montana in 1916.  It is native to northern Eurasia and has been introduced onto every continent in the world.  This plant probably arrived in North American via contaminated alfalfa seed.  Whitetop can be found in 54 of 56 Montana counties and infests a total of around 32,000 acres.  This plant is generally found in disturbed habitats that are associated with other weed species.

Concerns

Whitetop is an herbaceous, relatively long-lived, rhizomatous perennial weed.  It tends to form dense monocultures, which displace native plant species and reduce biodiversity, wildlife habitat, and forage production.  Whitetop is of major concern because of the difficulty to control.  This plant has a root system similar to leafy spurge.  The root growth is rapid.  The vertical taproot can reach depths of 12-30 feet by the second or third growing season.  This taproot develops several lateral roots that eventually turn downwards and become taproots themselves often reaching greater depths than the parent taproot.  All of these roots develop buds, which turn into rhizomes and shoots.  This complex root system combined with the ability of a single plant to produce between 1,200 and 4,800 seeds each year are the reason that it is so difficult to control.  It is also a major concern because it can be toxic to cattle.

Identification

Growth begins early in the spring for this plant because it germinates in the fall.  Blue-green lance shaped leaves appear in a basal rosette very early.   The stem leaves are also a blue-green color with the lower leaves on stalks and the upper leaves clasping the stem.  The flowers are white and consist of four petals laid out in a cross.  The individual flowers are small but dense clusters of the flowers create the white, flat-top appearance.  The seed capsules are broad, flat, and heart-shaped.

What can you do?

If you have a small infestation hand pulling can provide control.  For the control to be successful all underground parts of the plant must also be removed and it may take 2-4 years for complete eradication.  Mowing the plant to ground level will reduce biomass and seed production but does not provide long term control.  Whitetop can be controlled using herbicides but it is difficult and requires aggressive reapplication.  Another option is using sheep to graze on this plant.  The best method for the control of Whitetop is an integrated weed management plan utilizing all of the above options with prolonged effort.  If you have any questions or think that you have a patch of Whitetop on your property call your local county weed district.

Visit the MWCA Weed ID pages for additional information and pictures of whitetop.

This series of articles was developed by Ravalli County.  If you would like to use these articles please contact Ravalli County Weed District Weed Coordinator at (406) 777-5842.

Yellow starthistle is found close to the western border of Montana but has not yet successfully infested the majority of the state.  Due to its close proximity to us we need to seriously consider the potential it has to move in and rapidly infest our land.  It is thought that it was introduced to North America from the Mediterranean region, through contaminated seed.  Yellow starthistle is present in 23 states with the largest infestations in California, Idaho, Oregon, and Washington.  There are approximately 12 million acres infested with yellow starthistle in California and over 200,000 acres infested in Idaho.  Until recently only a few yellow starthistle plants had been found within Montana.  Last fall a small infestation was found in Beaverhead County.  A few weeks ago a larger infestation was discovered in Columbus, in Stillwater County.  This infestation is scattered throughout 10 acres.  This spring/summer will tell if the infestation is more widespread than what was found through identifying the standing dead plants remaining from last years growth.

Concerns

The spines that are located below the yellow flowers interfere with grazing, recreation, and wildlife management.  This plant is also toxic to horses.  It causes a chronic and potentially fatal neurological disorder that is commonly called “chewing disease”.  It earned this name due to the loss of the ability to apprehend and chew food.  However, swallowing is unaffected.  The animal will eventually starve to death due to this if it does not die due to inhalation pneumonia first.  There is no specific treatment to date and the irreversible localized necrosis in the brain gives a very poor prognosis.

Identification

Yellow starthistle is a winter annual with a deep taproot (up to depths of 6 feet).  Seeds germinate in the fall and overwinter as rosettes.  Fall germinated seedlings monopolize soil moisture and are highly competitive for nutrients and space.  In the spring, the rosettes will bolt producing branched erect stems with terminal flower heads.  Yellow starthistle is capable of growing in either wet or dry conditions and can respond rapidly to changing conditions.  It will produce large plants with abundant seeds during wet years and small plants with few flowers and seeds in dry years.

The flower heads consist of 20-50 small yellow individual flowers that are tightly clustered appearing as a single flower at the end of each branch.  Radiating out from below the flowers are up to 2 inch long straw colored spines.  The grayish to bluish-green stems are rigid and appear winged due to extending leaf bases.  The stems and leaves are covered in cottony hairs given the plant a whitish appearance.  The plant can be anywhere from 2-6 feet tall.

What can you do?

This plant is a new invader to Montana and therefore requires immediate action and hopefully eradication.  If you have found or think you have found yellow starthistle contact your county weed coordinator before initiating any control.  This plant is a rapid colonizer and germinates quickly under most conditions.  Dense seedbanks and length of seed viability make this plant extremely difficult to control and this is why it is important to locate new infestations and eradicate them prior to seed production.  The seeds can remain viable in the soil for up to 10 years.

Herbicides are the recommended method and most effective means of control when applied before the plants have flowered.  For recommendations on herbicide selection and timing contact the weed district and always follow the label directions.  Persistent hand pulling can be effective, as long as no flowers are allowed to go to seed.

Visit the MWCA Weed ID pages for additional information and pictures of yellow starthistle. If you have any questions about yellow starthistle or any other noxious weeds please contact your local county weed district.

This series of articles was developed by Ravalli County.  If you would like to use these articles please contact Ravalli County Weed District Weed Coordinator at (406) 777-5842.

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