1. Mission: The San Luis Valley Weed Management Association is a public and private partnership created to promote awareness and management of noxious weeds through local and regional initiatives in the SLV area.

2. This attractive succulent not only has pretty yellow flowers in the springtime, it harbors a dangerous secret: its sap, also called milky latex, can cause severe health problems. Myrtle spurge can cause respiratory problems in addition to skin irritation. The plant is toxic if ingested. For these reasons it is a plant that should be eradicated on all properties.

3. Invasion of L. salicaria into a wetland can result in the suppression of the resident plant community and the eventual alteration of the wetland's structure and function. Large monotypic stands of L. salicaria jeopardize various threatened and endangered native wetland plants and wildlife by eliminating natural foods and cover. Dense plant establishments in irrigation systems has impeded the flow of water

4.  This is an aggressive species that has invaded millions of acres of rangelands in the western United States. Cattle feeding on it may be poorly nourished and can be damaged by the spiny heads. Horses may be poisoned and develop chewing disease.

5. Bull thistle prefers sunny, open areas and can tolerate a wide range of conditions, from moist to dry soils, and is typically found in disturbed areas such as roadsides, trails, logged areas, vacant land, pastures and cultivated land. Overgrazed pastures are susceptible to bull thistle encroachment, and it can sometimes form dense stands that reduce productivity and stocking levels. Bull thistle may also dominate forest clear cuts and reduce growth of tree seedlings. Canada Thistle is a broadleaved weed with creeping roots that extend up to 17 feet (5 m) horizontally and 20 feet (6 m) deep. Unlike most other thistles, Canada Thistle (Cirsium arvense) is a perennial.

6.  Black henbane is a cultivated ornamental plant and that has spread throughout the United States. It contains hyoscyamine and other alkaloids which have been known to cause occasional livestock poisoning. It is also considered a poisonous plant to humans. In the past 25 years Chinese clematis has spread especially rapidly, becoming weedy and constituting a threat to young trees and native shrubby and herbaceous species (Flora of North America Editorial Committee 1997 ).

7. It has been a common weed of roadsides and other disturbed areas and recently has begun to invade valuable agricultural lands in the San Luis Valley. Viable seed is spread easily thru roadside mowing and in many other ways.

8.  Mature plants are strongly competitive, especially with shallow- rooted perennials and winter annuals. Dalmatian toadflax causes negative impacts in pastures, rangelands, and natural areas, where it outcompetes natives or other desirable species.

9. DAME’S ROCKET IS A TALL, SHOWY, SHORT LIVED PERENNIAL IN THE MUSTARD FAMILY. A PROLIFIC SEED-PRODUCER, IT HAS ESCAPED FROM GARDENS AND NOW INVADES ROADWAYS, WOODLAND EDGES AND FOREST INTERIORS. DIFFUSE KNAPWEED HAS LITTLE VALUE AS FORAGE FOR CATTLE AND LIMITED SEASONAL VALUE FOR BIG GAME. INFESTATIONS INCREASE PRODUCTION COSTS FOR RANCHERS, DECREASE PLANT DIVERSITY AND WILDLIFE HABITAT, INCREASE SOIL EROSION RATES AND POSE WILDFIRE HAZARDS.

10. HOARY CRESS IS INVADING RANGELANDS THROUGHOUT NORTH AMERICA. IT IS A HIGHLY COMPETITIVE WEED ONCE IT BECOMES ESTABLISHED. HOARY CRESS SPREADS PRIMARILY BY EXTREMELY PERSISTENT ROOTS AND WILL EVENTUALLY ELIMINATE DESIRABLE VEGETATION AND BECOME A MONOCULTURE. HOUNDSTONGUE IS A VERY STRONG COMPETITOR OF DESIRABLE FORAGE AND IS POISONOUS. IT CONTAINS PYRROLIZIDINE ALKALOIDS THAT STOP THE REPRODUCTION OF LIVER CELLS. SHEEP ARE LESS SUSCEPTIBLE THAN CATTLE OR HORSES. IT CAN ALSO CAUSE DERMATITIS IN HUMANS.

11. Jointed Oatgrass Jointed oat grass is a troublesome winter annual in winter wheat- fallow production areas. It can hybridize with winter wheat and reduce wheat crop yields.

12. LEAFY SPURGE IS TOXIC TO SOME ANIMALS AND REDUCES THE LIVESTOCK CARRYING CAPACITY OF PASTURE AND RANGELAND BY 20 TO 50%, CAUSING AN ESTIMATED $35-45 MILLION LOSS PER YEAR IN US BEEF AND HAY PRODUCTION IN ADDITION TO THE MILLIONS OF DOLLARS SPENT FOR CONTROL. MUSK THISTLE IS SIMILAR TO CANADA THISTLE ( CIRSIUM ARVENSE [L.] SCOP.) AND BULL THISTLE ( CIRSIUM VULGARE [SAVI.]), BOTH OF WHICH ARE ALSO NON-NATIVE. THERE IS SOME EVIDENCE OF HYBRIDIZATION OCCURRING BETWEEN MUSK THISTLE AND NON-NATIVE PLUMELESS THISTLE ( CARDUUS ACANTHOIDES [L.]). MUSK THISTLE IS DISTINGUISHED FROM OTHER THISTLES BY THE USUALLY LARGE DISK- SHAPED FLOWERS.

13. Oxeye Daisy The oxeye daisy is short- lived perennial originally brought here from Europe. The dainty flowers have escaped cultivation and now crowd out other plants on many rangelands. A vigorous daisy can produce 26,000 seeds per plant, while smaller specimens produce 1,300 to 4,000 seeds per plant. Tests have shown that 82% of the buried seeds remained viable after six years, and 1% were still viable after 39 years. Oxeye daisy requires cold winters to initiate blooming. The plant also reproduces vegetatively with spreading rootstalks. Daisies are resistant to many herbicides.

14.  Perennial pepperweed (Lepidium latifolium) is an extremely invasive perennial forb introduced from Europe and Asia in 1900 as a containment in sugar beet seed. Pepperweed reproduces both by seed and vegetatively by roots and shoots. Root fragments as small as 0.5 inch can grow into new plants. A serious threat, pepperweed alters ecosystems by acting as a “salt pump” absorbing salts from deep in the soil. The plant then excretes the salt through the leaves and deposits it on the surface soil. Since most desirable plants do not tolerate plant composition and diversity high saline concentrated soils, the entire of the area changes.

15. PLUMELESS THISTLE INVADES PASTURES, MEADOWS, AND FIELDS CROWDING OUT DESIRABLE FORAGE PLANTS. LIVESTOCK WILL NOT GRAZE IN AREAS HEAVILY INFESTED WITH PLUMELESS THISTLE QUACKGRASS, AN AGGRESSIVE PERENNIAL WEED, IT HAS A DEEPER ROOT SYSTEM THAN CRABGRASS AND REEMERGES EVERY YEAR. IT REPRODUCES FROM SEEDS AND UNDERGROUND RHIZOMES. THE RHIZOMES ARE VERY AGGRESSIVE AND MAKE CONTROLLING THIS PLANT VERY DIFFICULT. QUACKGRASS HAS AURICLES THAT CLASP AT THE STEM WITH HAIRY LEAVES. THE BEST WAY TO CONTROL THIS PLANT IS WITH A NON-SELECTIVE HERBICIDE LIKE GLYPHOSATE.

16. RUSSIAN KNAPWEED IT IS AN AGGRESSIVE INVADER OF PASTURES, NON-CROP AREAS, GRAIN FIELDS AND OTHER CULTIVATED FIELDS. IN ADDITION, THE PLANT IS POISONOUS TO HORSES, CAUSING CHEWING DISEASE (EQUINE NIGROPALLIDAL ENCEPHALOMALACIA). LIVESTOCK MAY AVOID THIS SPECIES. THE RUSSIAN OLIVE, WITH ITS TENDENCY TO SPREAD QUICKLY, IS A MENACE TO RIPARIAN WOODLANDS, THREATENING STRONG, NATIVE SPECIES LIKE COTTONWOOD AND WILLOW TREES. THEY ARE RESPONSIBLE FOR OUT COMPETING A LOT OF NATIVE VEGETATION, INTERFERING WITH NATURAL PLANT SUCCESSION AND NUTRIENT CYCLING AND CHOKING IRRIGATION CANALS AND MARSHLANDS IN THE WESTERN UNITED STATES. THIS DISPLACEMENT OF NATIVE PLANT SPECIES AND CRITICAL WILDLIFE HABITATS HAS UNDOUBTEDLY AFFECTED NATIVE BIRDS AND OTHER SPECIES. THE HEAVY, DENSE SHADE OF THE RUSSIAN OLIVE IS ALSO RESPONSIBLE FOR BLOCKING OUT SUNLIGHT NEEDED FOR OTHER TREES AND PLANTS IN FIELDS, OPEN WOODLANDS AND FOREST EDGES. THE RUSSIAN OLIVE HAS BEEN CATEGORIZED AS A NOXIOUS WEED IN NEW MEXICO AND UTAH. THERE IS A SERIOUS CONCERN THAT SHOULD THE RUSSIAN OLIVE CONTINUE TO ESTABLISH ITSELF, IT WILL BECOME THE DOMINANT WOODY PLANT ALONG COLORADO’S RIVERS, WHERE IT IS ALREADY TAKING OVER HUNDREDS OF THOUSANDS OF ACRES OF COTTONWOOD AND WILLOW WOODLANDS. SOME CITIES ARE ALREADY TAKING STEPS TO REMOVE THE RUSSIAN OLIVE.

17. Salt cedar is a shrub or tree native to the Mediterranean, China and Central Asia. This plant is found infesting waterways throughout the west. These plants contain salt that they deposit onto the soil through their leaves. Other riparian species are unable to survive the salty conditions and Salt cedar can then become the only plant growing in an area. Some reports show that one acre of Salt cedar can use 7.7 acre feet of water a year (2.8 million gallons). Although this plant has been sold as an ornamental in the past, it is no longer allowed to be sold in Colorado.

18. Scotch Thistle Scotch thistle is a problem in rangeland. Infestations of Scotch thistle reduce forage production and virtually prohibit land utilization for livestock. Dense stands of the large, spiny plants exclude animals from grazing and access to water. How would I identify it? Scotch thistle is a branched, biennial or annual with a broadly winged stem that can grow up to 8 feet or more in height and 6 feet in width.

19. YELLOW TOADFLAX, BUTTER AND EGGS, WILD SNAPDRAGON, COMMON TOADFLAX, RAMSTED, FLAXWEED, JACOB'S LADDER SPOTTED AND RUSSIAN KNAPWEED ARE TWO MEMBERS OF THE SOUTHWEST'S “DIRTY DOZEN ”INVASIVE WEED SPECIES. SPOTTED KNAPWEED (CENTAURIA MACULOSA LAM.) IS A SHORT-LIVED, NONCREEPING PERENNIAL THAT REPRODUCES FROM SEED AND FORMS A NEW SHOOT EACH YEAR FROM A TAPROOT.SPOTTED KNAPWEED (CENTAURIA MACULOSA LAM.) SPOTTED KNAPWEED CAN BE CONTROLLED WITH HERBICIDES; HOWEVER, THE WEEDS WILL REINVADE IF CULTURAL TECHNIQUES ARE NOT INTEGRATED INTO THE MANAGEMENT PLAN.

20. The San Luis Valley Weed Management Association partners with the following in our mission “to promote awareness and management of noxious weeds through local and regional initiatives in the SLV area.”

21. National Park Service and the Great Sand Dunes San Luis Central Railroad Company Rio Grande National Forest USBR CDOT Colorado State Land Board Mineral County San Luis & Rio Grande Railroad USFWS CDOW Colorado State Parks San Luis Water Conservancy District Denver and Rio Grande Historical Foundation Center Conservation District Colorado State Forest Service Conejos Conservation District Costilla Conservation District Mosca-Hooper Conservation District Rio Grande County Conservation District Bowen Drain Ditch Company Monte Vista Canal Rio Grande & Piedra Rio Grande San Luis Ditch Lariat Ditch Rio Grande Canal Farmers Union Canal

22. San Luis Valley Noxious Weed Management Association