Invasive Plant Focus: Bur Buttercup, Ranunculus testiculatus

Bur Buttercup, Ranunculus testiculatus: plants emerge, flower, and form fruit in the early spring, soon after snow-melt. Bur Buttercup is a native to southeastern Europe. It has become a common weed in small grains, pastures, waste areas and along roadsides in several western states including California, Oregon, Washington, Nevada, Utah, Idaho and Colorado. Bur Buttercup can be competitive, especially in dryland small grain crops. It is highly toxic to sheep. -Weeds of the West, by Tom D. Whitson

It is important to control Bur Buttercup before flowers and seeds are produced.

Invasive Focus: Kochia (Bassia scoparia)

Kochia is a summer annual – seedlings emerge in early spring. It has inconspicuous flowers that form spikes in leaf axils. The leaves are grayish in color, are smooth on top and hairy on the bottom. Kochia can grow from 1 to 6 feet tall with numerous branches. Seeds last less than one year and disperse through a “tumbleweed” process. After the plant has reached the end of its lifecycle, with strong winds it can break off at the base of the stem and form into a tumbleweed. The tumbleweed is easily blown around and usually ends up in fencerows, roadsides, etc, spreading seed on the way.

Kochia prefers disturbed and overgrazed sites, and is typically not a problem where healthy stands of perennial grasses exist.

Mowing the plants before flowering is effective in reducing seed production.

(photo and info source: Colorado Noxious Weeds)

Invasive Focus: Musk Thistle, Carduus nutans

Musk thistle, Carduus nutans, is a biennial or winter annual that can grow up to 8 feet tall. Leaves are up to 10 inches long, dark green with a light green midrib, spiny, and deeply lobed. Solitary, lightly spiny, and nodding flower heads develop at the stem tips in midsummer and grow to a diameter of 1½ to 3 inches. Blossoms are deep rose to violet or sometimes white in color. Seeds are 3/16 inch long, shiny, yellowish-brown, and have a hairlike plume. (Idaho’s Noxious Weeds)

Cultural/Mechanical Control: Establishing lush stands of desirable vegetation can aid in preventing establishment. Avoid bare areas in vegetation, as bare areas are prime habitat for many noxious weeds. Any method that injures the root below ground will kill musk thistle. Mowing or cutting heads at full bloom will reduce musk thistle populations. Be sure to bag or destroy plants that are removed to prevent seed from developing.

Biological Control: There are two weevil species (the seed head weevil, Rhinocyllus conicus and crown weevil, Trichosirocalus horridus) that impact large thistle populations. Both species are necessary for best results and they will provide fair to good control.

The Invasive Dyer’s Woad

Dyer’s Woad, (Isatis tinctoria). First year rosettes may look small on the surface, but the roots of this particular plant were 18 inches long!

Along the Ruby Pipeline, Weed Control

Hillside of Dyers Woad going to seed.Dyer’s Woad spreads primarily by seed.In this photo, you can clearly see first year rosettes and flowering Dyers Woad.

CSR recently finished a section of a weed abatement project along the Ruby Pipeline ROW. This particular section of pipeline was located near Brigham City, UT. One of the most prevalent weeds found was Dyer’s Woad, (Isatis tinctoria). **This striking yellow plant is native to southeast Russia and is sometimes found as a garden ornamental in the western US. Dyer’s Woad is a non-palatable, aggressive weed with allelopathic properties (it produces chemicals which inhibit growth in other plants close by). This species has a history of establishing across thousands of acres of western rangeland, and infestations are known from eight western states. **Idaho Weed Awareness Campaign

Crews collected the seed heads to help reduce the seed bank of this highly invasive species. Licensed herbicide applicators then followed behind spot-spraying the weed. This was a very tedious job as the plants first year rosettes are small and one can find many on an infested hillside.

Also found along the way was Yellow Starthistle, Centaurea solstitialis. This invasive weed is listed as “Class A” weed and have a relatively low population size within the state of Utah and are of highest priority being an Early Detection Rapid Response (EDRR) weed.

Invasive Focus: Brown Marmorated Stink Bug

The brown marmorated stink bug, Halyomorpha halys, is an invasive pest, that is becoming wide-spread in the U.S. and is of concern to farmers. It feeds on a large number of high-value crops and ornamental plants in its immature and adult life stages. The species is native to Asia and was introduced into the United States in the mid-1990s, possibly stowing away in a shipping container. Their numbers and range have been growing since that time, and they have proved difficult to manage.

In 2010, these stink bugs were seen in extremely high numbers in the mid-Atlantic region. They were responsible for causing major economic damage to fruits and vegetables on a number of farms. In addition to plant damage, brown marmorated stink bugs are a nuisance to people. Adult stink bugs may seek shelter inside houses and other buildings, although they do not bite people or pets, nor do they damage buildings. (EPA:Controlling Pests)

Brown Marmorated Stink Bugs were recently found in Idaho.

The Non-Native Bulbous Bluegrass, Poa bulbosa

Bulbous Bluegrass, Poa bulbosa, is a perennial that grows from basal bulbs, the culms closely clustered, 1/2 to 2 feet tall. The leaf blades are narrow, flat or loosely rolled; with membranous ligules about 1/8 inch long. Flowers are modified to bulblets with a dark purple base.

Introduced from Europe, bulbous bluegrass is now weedy in pastures, grain fields and roadsides in scattered areas of most states. (Weeds of the West)

Bulbous bluegrass was likely a contaminant in grass and/or clover seed imported by the United States. It originated near Portland, Oregon, an active shipping port, spread into Washington and progressed eastward to northern Idaho and western Montana between 1891 and 1980. (USDA Forest Service)

Invasive Species on the Move

The following is shared from the frequently asked questions page on the Center for Invasive Species Research website…

How do invasive species move from place to place?

Invasive species reach new areas outside of their home range in one of two ways: (1) self introduction on their own, or (2) with human assistance that may be deliberate or accidental.

Self-introduction of species into new areas is not a new phenomenon. This process has been happening for millions of years at a very slow rate, and often introductions occur between close neighbors. For example, New Zealand has acquired bird, plant, and insect species that are carried by winds across the Tasman Sea from Australia.

Humans have greatly altered the speed at which species are moved around the world and species introductions are occurring between areas that are separated by vast distances and across natural barriers (e.g., oceans and mountains) that had previously prevented the long-distance movement of species. The speed at which long-distance spread can happen has greatly accelerated due to air travel which allows people to reach most places on earth within 72 hours or less. Short travel (hours on a plane as opposed to weeks or months on a boat at sea) times have greatly increased the survival chances of invasive species traveling with humans.

Humans have deliberately moved an incredible number of plant and animal species around the globe either for food, as part of international commerce (e.g., the pet and nursery trade), or for sport (e.g., hunting and fishing).  It is estimated that there are 50,000 non-native species of plants and animals living in the USA.

Occasionally, some of these species that were once beneficial while under human control (e.g., weeds that were originally garden plants) become problematic when they escape and start to colonize and breed in areas where they are not wanted. For example, plants like salt cedar from Eurasia have invaded the desert southwest of the USA because humans deliberately moved them there for the control of constantly eroding desert sands.

Often, invasive species are moved accidentally by humans. This can occur through hitch-hiking unnoticed on plants that are being moved (e.g., tiny insects or diseases on leaves or in potting), in ballast water that is used to stabilize large transport ships, or inside other animals (e.g., diseases that kill birds have been spread by the commercial trade in exotic pet birds.)

Air Traffic: The above video shows world air flight traffic over a 24 hour period. Notice how the number of planes flying changes between daytime and nighttime. Even at night there are still lots of planes flying around the world. Every flight can potentially move an invasive species into a new area.

Invasive Plant Focus: Poison Hemlock, Conium maculatum

Poison Hemlock (Conium maculatum) is noted for its toxicity. It is a herbaceous biennial plant which grows between 1.5-2.5 m tall, with a smooth green stem, usually spotted or streaked with red or purple on the lower half of the stem. The leaves are finely divided and lacy, overall triangular in shape, up to 50 cm long and 40 cm broad. The flowers are small, white, clustered in umbels up to 10-15 cm across. The plant is often mistaken for fennel, parsley or wild carrot although the characteristic stem hairs of the wild carrots are missing. The Poison Hemlock root is fleshy, white and often unbranched and can be mistaken for parsnip. When crushed, the leaves and root emit a rank, unpleasant odour often compared to that of a mouse or parsnips. One of the distinguishing characteristics of Poison Hemlock is the purplish spots on the stems.

Poison Hemlock contains the alkaloids Coniine, N-methylconiine, conhydrine, pseudoconhydrine, g-coniceïne and Atropine . The most important and toxic of these is Coniine. Coniine is a neurotoxin, which disrupts the workings of the central nervous system and is toxic to people and all classes of livestock.

Poison Hemlock has been introduced and naturalised in many other areas, including much of Asia, North America and Australia. Poison hemlock is often found on poorly drained soils, particularly near streams, ditches, and other surface water.
(photos and info source: Idaho Weed Awareness)

Invasive Plant Focus: Russian-Thistle, Salsola tragus

Photo: Forest & Kim Starr, Starr Environmental, Bugwood.org

Photo: Mary Ellen (Mel) Harte, Bugwood.org

Russian thistle, Salsola tragus, also known as tumbleweed, is in the goosefoot family (Chenopodiaceae). Its scientific name is Salsola tragus, but it also has been known as Salsola iberica, Salsola kali, and Salsola australis. It is a summer annual native to southeastern Russia and western Siberia and was first introduced into the United States in 1873 by Russian immigrants as a contaminant in flax seed in South Dakota. After its introduction, it spread by contaminated seed, threshing crews, railroad cars (especially livestock cars), and by its windblown pattern of seed dissemination. In 1895 Russian thistle moved to the Pacific Coast in contaminated railroad cars that transported cattle to Lancaster in California’s Antelope Valley. Today it is common throughout the western United States—having invaded about 100 million acres. It is particularly well adapted to California’s climate of winter rainfall and summer drought.

Russian thistle is primarily a weed in sites where the soil has been disturbed, such as along highways and fencelines. It is also prevalent in vacant lots and other noncrop areas, in field and vegetable crops, and in poorly tended landscapes. It is rarely a problem in well-managed gardens or turfgrass.

Russian thistle is a bushy summer annual with numerous slender ascending stems that become quite woody at maturity. Stems vary from 8 to 36 inches in length and usually have reddish to purplish stripes. Seedlings have very finely dissected leaves that almost look like pine needles. Leaves of young plants are fleshy, dark green, narrow, and about 1 inch in length. Young plants are suitable for livestock forage and are sometimes grazed. As the plant matures in July through October, the older leaves become short and stiff with a sharp-pointed tip. The single, inconspicuous flowers lack petals and are borne above a pair of small spine-tipped bracts (a small modified leaf at the base of the flower) in most leaf axils (where the narrow leaves meet the stem). The bracts and spiny leaves prevent predation by herbivores as the plant nears maturity. The overall shape of the plant becomes oval to round and at maturity can attain a diameter of 18 inches to 6 feet or more under favorable soil moisture and fertility conditions. After the plant dries, the base of the stem becomes brittle and breaks off at soil level in fall and early winter. These round, spiny plants are capable of dispersing seed for miles as they tumble along in the wind. This dispersal characteristic has led to the more commonly used name of tumbleweed. (source)