What is a ‘noxious weed’? A ‘noxious weed’ is any species of plant that is, or is liable to Fighting be, troublesome, aggressive, intrusive, detrimental, or destruc- tive to agriculture, silviculture, or important native species, the Weed Wildfire and difficult to control or eradicate (definition as per the Cali- fornia Food and Agricultural Code). Yolo County’s Noxious Weeds A common characteristic of all noxious weeds is their aggressive, competitive behavior. Typically, they steal pre- The Yolo County Weed cious moisture, nutrients, and sunlight from surrounding Management Area (YWMA) plants thus, impacting native vegetation. The Yolo County Weed Management Area (YWMA) was formed by federal, state, county, city, private industry, and landowners that are concerned about the explosion of invasive Yolo County’s noxious weeds plant species in Yolo County. weeds of special concern Our goal is to educate the public on noxious and invasive weeds.This brochure is the first step in increasing the public awareness of what is a noxious or invasive weed. upland weeds Barbed Goatgrass Aegilops triuncialis Additional Partners Medusahead Taeniatherum caput-medusae L. City of Woodland • City of Davis •Yolo County Farm Bureau • Yolo County Department of Public Works • Cal-Trans •Yolo Yellow Starthistle Centaurea Solstitialis L. County Flood Control • County Parks, California Department of Forestry • Reclamation Districts •Yolo Shortline, California Iberian thistle Centaurea iberica Northern Railroad, local Fire Districts •Yolo County Cattlemen Perennial Pepperweed Lepidium latifolium L. & Woolgrowers • California Native Plant Society • Cache Creek or Tall Whitetop Conservancy • California Department of Water Resources • California Department of Fish & Game • Natural Resources Puncturevine Tribulus terrestris L. Conservation Service •Yolo Basin Foundation • University of California, Davis • Community Alliance with Family Farmers. Rush Skeletonweed Chondrilla juncea L. Klamathweed or For additional information St. Johnswort Hypericum perforatum please contact: Yolo County Department of Agriculture riparian weeds www.yolocounty.org Tree of Heaven Ailanthus altissima (530) 666-8140 Yolo County Farm Advisor, Giant Reed Arundo donax UC Cooperative Extension Tamarisk Tamarix parviflora (530) 666-8143 Yolo County Resource Conservation District aquatic weeds www.yolorcd.ca.gov/weeds/ (530) 666-2037 ext. 3 The mission of the Yolo County Weed Management Area Water hyacinth Eichhornia crassipes The Yolo County Weed Management Area (YWMA) (YCWMA) is to promote and coordinate the management, www.cdfa.ca.gov/wma control and efforts toward eradication of the County’s nox- To find out the state of any noxious weed or invasive weed in California ious weeds through education and cooperation with land contact any County Agricultural Commissioner’s office. owners, agencies, organizations, and the general public. Preventing the introduction Control is an annual task, Now that you have of noxious weeds not a one year miracle identified and gained some The transportation of contaminated hay, seeds, flower Weed scientists and biological scientists state that control over your weeds, arrangements, nursery stock, and other apparently biological control options for noxious weeds are TION what is the next step? harmless purchases have introduced many noxious expanding at a rapid rate. However, they caution weeds to California. Some so-called noxious weeds are that biological control is not and never will be a Whenever you make the effort to control weeds, you escaped ornamental plants that have gone wild, like Tree cure all or total replacement for judicious herbicide A will be faced with having bare ground in their place. of Heaven, fertile Baby’s Breath, or Purple Loosestrife. use. Instead, scientists stress that successful long- That bare ground will soon be re-infested with a new Most people are unaware that bringing even one plant term management of noxious weeds relies on a set of weeds unless you replace them with desirable or seed packet across state borders can create a new combination of biological, chemical, cultural, and plants.There are many types of plants that are well plant infestation.This can disrupt native vegetation. physical methods an integrated approach. Integrated adapted to your specific site. weed management and improved land management Prevention and early detection allows us to eradicate Perennial broadleaf plants or grasses are the most are the answer. new outbreaks and devote our principle efforts toward ideal. Once these plants are established, they will out

management and containment of existing, large-scale CONTROL compete any weeds that might try to move into your infestations. Types of weed control methods new weed free area. Certain annual grasses, or even cereal grains like 3 Cultural control method: Includes, but is not wheat or barley, will provide a quick competitive cover Prevention tips limited to, mowing, burning, mulching, hand pulling, to help discourage new weeds from becoming estab- 3 grazing, and cultivation. Always check your vehicle for plants or seeds when lished, or previously existing weeds from coming back. 3 leaving an infested site. Chemical control method: Consists of applying Be cautious however, of annual grasses.They can 3 Be aware when moving dirt, compost, or equipment pre and post emergence products.There are selec- become weeds themselves if left unattended.

PREVENTION since seed can be viable for up to 10 years. tive and non-selective products.Always read the Remember it is important to plant something back in label directions before using any herbicide. 3 Do not be tempted by attractive flowers from other the newly weed free areas, or you will find yourself 3 states or counties. Do not introduce its seeds or Biological control method: Involves a specific pred- waging a never-ending battle with weeds. For help with seedling into the state or county. ator for a specific weed. Usually insects are the control finding the right plant for your area, contact your local 3 mechanism. Used for long term projects, results will no Agricultural Commissioner, UC Cooperative Extension

Report known locations and sightings to the Yolo REVEGET be noticeable for several years. Is compatible with most office, or the local Resource Conservation District. County Agricultural Commissioner’s office. cultural and chemical control methods. 3 Tell neighbors and friends about noxious weeds. 3 Join the Yolo County Weed Management Area. Weed control steps 3 Identify the weed to be controlled 3 Write down the location and size of the infestation. 3 Determine control method(s) and timing. 3 Re-establish desired plant species after control method is used. 3 3 Always monitor for re-infestations. p Puncturevine Yellow Starthistle Medusahead Tribulus terrestris L. Centaurea Solstitialis L. Taeniatherum caput-medusae L. Other names:goathead, caltrop, and Background:Native to southern Europe. Background:Native to Eurasia. Mexican or Texan sandbur. Identification: Annual 1 to 3 feet, erect and Identification: Aggressive winter annual _ Background:Native to Mediterranean. rigid branching, from taproot. Stems rigid, to 2 feet. Leaf blades generally 1/8 inch Identification: Annual with prostrate or winged, and covered with cottony pubescence. wide or less, rolled. Inflorescence long somewhat ascending, mat forming, trailing Basal leaves deeply lobed (as are leaves of awned spike nearly as wide as long. Mature stems, each about 1 to 5 feet long. Leaves seedlings); upper leaves entire and sharply awns or beards twisted 1 to 4 inches long, opposite, hairy and divided into 4 to 8 pairs pointed. Flowers yellow, terminal armed with stiff, finely barbed. Sometimes confused of leaflets. Flowers yellow, with 5 petals. straw-colored thorns approximately 1 inch with foxtail or squirrel tail, however spike Fruit hard, on underside of stem, separating across. Outer seed dark brown without bristles; heads does not break apart as seed mature. into five parts when mature, each with 2 to inner seed mottled light brown with a tuft of Individual awned-florets fall away, leaving a 4 sharp hard spines, resembling a goat’s white bristles, about 1/8 inch long. Flowers bristly head of awn-like glumes that will head. Flowers April to October May to October. persists over winter. Distribution:Grows in pastures, cultivated Distribution:Invades various soil types on waste Distribution:Extremely competitive, fields, waste areas, and disturbed sites such areas, road-sides, pastures, and dry rangelands. crowding out many native and desirable as roadways.Toxic to livestock in vegetative Toxic to horses, as it causes “chewing disease”. plants, invading millions of acres of semi- condition. It particularly thrives in sandy Once this plant invades a site it may sit without arid rangeland.Appears most common on and sandy loam soils.The hard spiny burrs increasing for several years. It becomes genetically high shrink-swell clay soils. Infested range- damage wool, and may be injurious to live- adapted to that site and then the population lands have suffered up to 75% reductions in stock as well as humans’ bare feet, dogs’ explodes; it spreads rapidly. Much of California grazing capacity. Introduces fire into non- pads and bike tires. Puncturevine is wide- is heavily infested with yellow starthistle. It is fire prone ecosystems. Control of small, spread throughout northeastern California continually spreading into the, Sierra Mountains, isolated infestations is critical. Medusahead and northwestern Nevada with scattered where it has not been previously know to occur. is found scattered throughout California. occurrence. Small populations must be eradicated!

Tree of Heaven Rush Skeletonweed Klamathweed or Ailanthus altissima Chondrilla juncea L. St. Johnswort Background: It is native to East Asia. Background:Native to southern Europe. Hypericum perforatum Identification: It is fast-growing perennial Identification:A much branched biennial Background:Native to Europe. shrub/tree. Mature plants have bark that is or perennial, 1 to 4 feet, with milky sap. Identification: Perennial 1 to 3 feet with thin, gray and slightly rough.They have a Lower 4 to 6 inches of stem have down- erect, tow ridged stems and numerous rust flat-topped form and height can be 20 to 60 ward bent, coarse reddish hairs. Leaves colored branches. Leaves opposite, oblong, feet (6 to 18 meters).The leaves of Tree of form basal rosettes, sharply toothed, that entire, covered with tiny transparent dots. Heaven are 1 to 3 feet long and have 13 to wither as stems develop. Stem leaves incon- Flowers numerous, bright yellow, with five 25 leaflets arranged on opposite sides of the spicuous, narrow and entire. Flowers scat- separate petals that twist after flowering. stalk.The leaflets are 3 to 5 inches long tered on branches, less than 1 inch across, Petals have occasional minute black dots and 1 to 2 inches wide. The leaflets are with 7 to 15 yellow, strap-shaped petals around the edges. Stamens numerous, toothed at the base and have an unpleasant odor if crushed. Flowers with 5 distinct teeth at the end. Seeds pale arranged in three groups. Flowers June can be male, female, or both male and female.They consist of 4 to 8 brown to nearly black, about 1/8 inch long, to September. inch long, dense greenish panicles at the ends of branches.The plant several–ribbed, smooth below with tiny Distribution:Usually found in sandy or produces a spirally twisted winged fruit that is about 1-1/2 inches scale projections above, terminated by gravelly soils and along road-sides. Contains long, with a seed at the center of the wing.The greenish-yellow fruit numerous soft white bristles. Flowers July toxic substance, which causes animals that turn pinkish or reddish brown as they mature. Dense clusters of to September. eat it to lose weight and develop a skin seeds remain on the tree through the winter. Seeds germinate from Distribution:It generally grows in well- irritation when exposed to strong sunlight. April through June. Fruit matures from September through October. drained light textured soils along road- Klamathweed ranges from the Pacific Ocean Distribution: It produces many suckers, spreads by seeds and invasive sides, rangelands, grain fields, pastures and to east Nevada. roots and thrives even in poor soils. It was once cultivated as an orna- vineyards. Easily invades disturbed sites. mental but has escaped from cultivation and become well-established Extensive, deep root system makes rush in many areas of California. skeleton weed difficult to control. Giant Reed Perennial Barbed Goatgrass Arundo donax Pepperweed Aegilops triuncialis Other names: Common reed, False bamboo, or Tall Whitetop Background: It originates from Europe. Dumb cane Lepidium latifolium L. Identification: It is an annual plant. Height Background: Native to warmer southern ranges anywhere from 20-40 cm tall with few areas of Europe and was introduced to Other names:Whitetop to many culms.When young, the leaf sheaths California as an ornamental plant. Background: Native to southern Europe and contain white hairs, but once matured, they Identification: It is a perennial plant that western Asia. become more or less smooth.The blades are can grow 6 to 20 feet tall.The stems are Identification: Perennial 1 to 6 feet. Leaves rigid, sharp, pointed, and spreading. Flowers hollow, nearly woody, and about one inch in lanceolate, bright green to gray-green, smooth on this grass weed are spiked and grow to diameter. Leaves on the plant are arranged to toothed margin. Basal leaves larger than about 3 inches in length, including the awns. in rows on each side of the stem.The leaf upper leaves.White flowers develop in dense The flowers contain 3-5 spikelets; the lower blades on the main stem are 1 to 3 inches clusters near the ends of branches. Fruit a ones are broad, while the upper ones are rudi- broad and flat. On smaller stems, the blades two-seeded capsule. Reddish-brown seeds, mentary. Glumes are very tough each ending are narrow.The blade margins are rough round, flat, slightly hairy, and about 1/16 inch in three stiff, stout and spreading awns.They and saw-like, while the base of the blade is long. Flowers June to August. are strongly veined and terminate in awns heart-shaped and slightly hairy. Flowers on Distribution: Grows in waste areas, wet areas, that are about one inch long.The grain is about the giant reed appear in large panicles, one ditched, road-sides, cropland, along waterways, 1/4 inch long, resembling a wheat kernel. to two feet long. Each spikelet contains sev- and dry habitats such as road cuts and fills. Distribution: It is found abundantly in areas eral long, hairy flowers that successively Robust, deep-seated spreading roots and throughout the Southwestern portion of grow shorter towards the tip.The rhizomes are tough, thick and knotty numerous seeds make this weed very difficult Calaveras County, overlapping into eastern and have many branches.The roots are stout and about 1/4 inch in diame- to control. outcompetes native vegetation and San Joaquin County and Northwestern ter. No viable seeds are produced in California. crop, forming in own monoculture.Attempts at Stanislaus County.Also found in Yolo and Distribution:It is troublesome along streams and canals. In these areas, mechanical removal can spreads the plant and Mendocino Counties. giant reed interferes with water flow, reduces stream capacity, and nega- increase its numbers. Control: Cattle grazing on land helps to tively impacts plant and animal diversity. reduce infestation.

Water hyacinth Tamarisk Iberian thistle Eichhornia crassipes Tamarix parviflora Centaurea iberica Other names: Pickerel-weed, floating Other names: Salt Cedar Other names: Iberian star thistle water hyacinth Background: Native to Eurasia. Background: Native to southeastern Background:Native to tropical America and Identification:This aggressive riparian Europe, and has been well-established in was introduced into the United States as an weed is a deciduous (sometimes evergreen) parts of California since the 1950’s. ornamental plant. shrub or small tree that grows 5 to 20 feet Identification:It is an annual or biennial Identification:Water hyacinth is a floating, tall.The stems are reddish-brown in color plant that grows to from 3 to 6 feet tall. It perennial, aquatic plant that has two leaf and even as saplings, have bark on them. has a cobweb-like fuzziness over most of the types.The underwater leaves are long and Leaves are small and scale-like, like those of plant and is a prolific seed producer.Young narrow and sometimes broader at the tips. juniper or cedar.They appear on highly plants form a rosette of deeply lobed basal Leaves found above the water surface are usually broad and nearly branched and slender stems.The flowers are leaves in late spring The upper leaves are round. Both leaf types are glossy and bright green and grow from a pink to white and are 5-petaled. [Another reduced and narrowly lobed. Flowering typ- central crown in rosette fashion.The leaf stalks appear inflated and type of tamarisk is the smallflower tamarisk ically occurs in July and August. Flowers are bladder-like.The mature plant can be up to 2 feet tall, and although it (T.parvifora D.C.). Smallflower tamarisk is pinkish-purple with straw-colored spines usually floats on the water, it can also root in mud. Roots are dark and similar in appearance as the salt cedar but has that are over 1 inch long surrounding the fibrous.The plants form stolons that produce new plants. Flower stalks 4-petaled flowers with brown to deep purple base. Seeds are light tan colored and have (8 flowers per stalk) are 12 to 14 inches tall with a single leaf and several bark on its stems. Smallflower tamarisk was short, flattened bristles attached to the top. tubular sheaths enclosing the upper portion. Flowers may be bluish- introduced from Southern Europe and is also purple or white.The upper petal of each flower is enlarged and has a widespread.] patch of blue or deep purple with a yellow blotch. Limited reproduction Distribution: Both species of tamarisk are widespread throughout the occurs by the seed, which is produced in a capsule. Flower stalks con- U.S. Both are most common along streams, canals, and reservoirs in taining mature seed droop over into the water and the seed develops the West.These plants are very invasive in riparian areas and displace underwater, dropping into the mud. native vegetation by competing intensely for ground water. Plants that Distribution: It can obstruct water flow in irrigation ditches and drainage develop on stream banks can inhibit the flow of the stream, exacerbating canals.This plant is now a serious aquatic pest in parts of the U.S. local flooding problems and causing property damage.