Presentation on theme: "Invasive Weeds on the Middle Fork Snoqualmie"— Presentation transcript:
1Invasive Weeds on the Middle Fork Snoqualmie Sasha ShawEducation SpecialistKing County Noxious Weed Program
2Agenda Weed Definitions Middle Fork Weed Priorities Priority Weeds Present in the WatershedClass A and B Noxious WeedsOther Priority Invasive WeedsOther Widespread Weeds and Lower Priority Plants Present but not SurveyedNoxious Weeds Threatening to Invade
3What is an Invasive Weed? Introduced / non-nativeAbility to out-compete native plantsLack of predators or natural controlsAbility to modify local ecologyAggressive ability to reproduceRapidly multiply to dominate a site and are extremely difficult to controlIntroduced to Washington either accidentally or on purpose by humansEvolved in other parts of the world, lack natural enemies such as plant-eating insects and diseases that normally keep their growth in check in their homelandAquatic invasive plants found in Washington were all originally brought here as ornamental plants for aquariums or water gardens. These ornamental plants tend to be naturally hardy and able to withstand the tough growing conditions found in aquariums. Thus, when they are introduced to Washington’s waters, they often thrive and out-compete native plants.Lack of natural enemies in the USHeavily planted: of the 124 state noxious weeds, 61 were introduced as ornamentalsMultiple forms of reproduction: many seeds, vegetative growth, fragmentsRapid growthEasily transported: burs, winged seedsInvasive knotweed is one of the toughest plants to control and damages some of the highest quality habitats
4What is a Noxious Weed?Non-native plant that impacts agriculture, wildlife, human health, land values or natural resourcesDefined and regulated by state law (RCW 17.10)county lists are chosen from the state listregulated in parts of the statewhere they have limited distribution
5What are the Weed Classes? Class A Weeds – new invaders, control required statewide, still a chance to eradicateClass B and C Designates – control required in King County, still have a chance to stop them from getting establishedNon-Designates and Weeds of Concern – widespread invasive weeds in King County, control not required but definitely a good idea whenever possible!
6Middle Fork Snoqualmie Weed Priorities King County Noxious WeedsClass A’s, B-designates, and C-selectsNon-designates and Weeds of Concern that are limited in distribution and still controllableNon-native species newly introduced or not previously reported in the valleyExcluded from the survey: species that are already pervasive in the valley and unlikely to be controlled valley-wide
7Middle Fork Snoqualmie Weed Surveys Completed 2005 and 2006 Roadsides (10 ft in on both sides)Farther in where disturbance or weed infestations were observedDisturbed SitesQuarries, cut banks, logging landingsCamping sites, pullouts, trailheads, parking lotsOpen talus fields, stream crossingsRiver by raft and river bars on foot
9Priority Weeds Identified in the Middle Fork Valley Himalayan and Evergreen BlackberryBohemian KnotweedScotch BroomReed Canary GrassEnglish HollyEnglish IvyButterfly BushTansy Ragwort*Yellow Hawkweed*Canada ThistleHedge BindweedCommon TansyYellow ArchangelYellow Flag IrisEuropean Mountain-AshSpotted Knapweed*Bittersweet NightshadePoison-hemlockListed in order of total area found. Weeds with * are designated for control in King County.
11Class A and B Noxious Weeds (Please notify the county noxious weed program if these are found)
12Tansy Ragwort (Senecio jacobaea) Class B Noxious WeedTansy Ragwort (Senecio jacobaea)Flowering stems are 1-6 ft tall with clusters of yellow, daisy flowersFirst year rosettes have round-lobed leaves, reddish stemsA biennial plant; rosettes the first year and in the spring; flowering stems the following year and in the summerFlowers June to October. Seeds are viable for 10 to 16 years.
13Tansy Ragwort (Senecio jacobaea) A biennial plant; rosettes the first year and in the spring; flowering stems the following year and in the summerControlsManual: Hand pull or dig up small infestations.Biocontrols: Cinnabar moth, ragwort flea beetleMechanical: Mowing is not recommended.Herbicide: Most effective to apply selective broadleaf herbicides in the spring and again in the fall. Glyphosate; 2,4-D on rosettes; metsulfuron and dicamba on growing plants.
14Yellow Hawkweed (Hieracium caespitosum) Flowers: Yellow, in tight clustersLeaves: Hairy on top and bottom, glandular and stellate hairsRoots: stoloniferous, rhizomatous
15Non-native Hawkweeds Stiff hairs on stems, leaves Basal rosette of spatula shaped leavesSmall flowers, often in tight clusters near tops of stemsFlower buds and bracts covered with black hairsStolonsLeaves mostly broader at tip than at base, 4-6 inches longNarrow at base to a short petioleLeaves usually hairyStems progressively less leafy from bottom to topEach rosette usually produces 1-8 flower stems, 2-36 inches tallMilky sapFlowers borne in clusters of 5-30 near top of stemHeads ½ to ¾ inch wide, seeds dandelion-like but shorterBlack hairs on flower buds
16Yellow Hawkweed (Hieracium caespitosum) Rosettes: March-AprilBolting: April-early JuneFlowers: May-JulySeeding: July to September
18Spotted Knapweed (Centaurea stoebe) Grows feet tall, perennialPink to purple flowers, on the tips of stem branchesFloral bracts tipped with dark fringeBolting: April to JulyFlowering: May to OctoberSeeding: August to OctoberReproduces by seedBlack tips on the bracts, giving a spotted appearanceSlender, wiry branchesIt grows throughout the Western United States on disturbed soil, preferably shallow and gravelly.Spotted knapweed will also invade healthy rangelands.The early spring growth makes them competitive for moisture and nutrients.ControlsBiocontrol: thirteen insect species; cattle, sheep or goat grazing useful in reductionDigging: best when done earlier in season when soil is moistMechanical: cutting or mowing prior to seed set provides reduction but not eliminationHerbicide: 2,4-D at early stem elongation, glyphosate when mostly in bud
21Himalayan Blackberry (Rubus discolor) Thrive in almost all types of areas in our climate, even in wetlands at times, but don’t grow well in full shadeForm impenetrable thickets (lowering plant diversity, providing habitat for rats, etc.)In less than 2 years, one cutting can produce a 15 foot diameter thicketOut-compete low growing natives and can prevent establishment of trees such as Douglas fir, pine and oakLimits movement of large animals between forest and small meadows for grazingA poor replacement for a diverse native forest understory or riparian floodplainTwo widespread, non-native blackberries: Himalayan blackberry (Rubus armeniacus or R. discolor) & evergreen blackberry (Rubus laciniatus); both very invasiveFrom Western Europe; introduced to US around 1885, naturalized by 1945
22Himalayan Blackberry (Rubus armeniacus, R. discolor) Robust, sprawling shrub with canes to 9 feet tall, feet longLarge thorns on stems, leaves and leaf stalksLeaves with 5 large, oval, toothed leafletsWhite to light pink flowers and large, black berriesThe stems, called canes, grow upright at first, then cascade onto surrounding vegetation, forming large mounds or thickets of the blackberry.While some canes stay more erect, growing up to 9 feet high, others are more trailing, growing feet long.The canes can take root at the tip when they hit the ground, further expanding the infestation.Thorns grow along the stems, as well as on the leaves and leaf stalks.The leaves are palmate, usually with 5 large, oval, toothed leaflets.The leaflets are dark green on the upper surface and grayish-green below.White to light pink flowers, which produce a large, juicy, blackberry.The berries, which ripen between midsummer and autumn, are used as food by birds, humans and other mammals.Canes start producing berries in their second year.Individual canes may live only 2 to 3 years, with new stalks sprouting from the root crown.Himalayan blackberry can be evergreen, depending on the site.
23Evergreen Blackberry (Rubus laciniatus) Leaves are lacy, deeply toothedSimilar growth form and invasiveness to Himalayan blackberryErect, spreading, or trailing evergreen shrub that gets very large and grows in dense, impenetrable thickets. Young stems are erect, but arch as they lengthen, eventually touching the ground and rooting at the nodes.Leaf has five leaflets, which have very divided edges, quite different than the leaves of the other blackberries, evergreen leaves are green on both sides, hairy on the undersideStems are stout, heavily ribbed, purplish-red, armed with heavy recurved pricklesFlowers are white to pink, appear in June, berries are blackAs with Himalayan blackberry, evergreen blackberry reproduces both vegetatively and by seed. It produces numerous suckers, and the stems will root upon touching the ground. After disturbance, evergreen blackberry usually sprouts vigorously.
24Good Guy Look-Alike: Native Trailing Blackberry (Rubus ursinus) Low-growing, trailing, often found in wooded areasStems are thin, green when young, brown when matureDensely covered with smallish thornsLeaves are evergreen, with 3 leaflets, green on top, lighter green underneathLeaf: Pinnately compound (usually 3 leaflets), alternate, persistent (often barely); leaflets ovate, lobed and doubly serrate, 1 1/2 to 3 inches long, dark green above and paler below. Rachis and petiole armed with slender, easily detached prickles. Flower: Mostly dioecious, mostly imperfect, white to pink, 1 to 2 inches across, narrow petals, borne in clusters.Fruit: Black aggregate of drupelets about 1/2 inch long, very edible.Twig/Bark: Slender, round, and green to red, but covered with a white, waxy bloom, armed with slender straight or recurved prickles that detach easily.Form: A climbing or trailing evergreen shrub with round, slender branches that commonly reach 10 to 20 feet in length. Young stems are erect, but arch as they lengthen, rapidly touching the ground and rooting at the nodes.
25Bohemian Knotweed (Polygonum bohemicum) Perennials with creeping rhizomesIntroduced as ornamentals; used like bambooHabitat: disturbed, riparian, wetlandImpacts: Dense colonies, exclude native vegetation
26Hollow, upright, bamboo like stems often reddish or red-speckled
27Typical stand of Bohemian knotweed naturally occurring hybrid between the other twomost common type of knotweed found in the Pacific Northwestmedium tall (8 to 12 feet), mixed leaf shapesintroduced as an ornamental separatelymost clones were male (flower clusters stiffly upright, no seeds)recently females have been showing up with viable seeds (oh no!)Typical stand of Bohemian knotweed
28Japanese Knotweed (Polygonum cuspidatum) Smaller than the others (6 feet usually)Leaf bases are flat, not heart-shapedMost clones in US are female (will have seeds later in season)Flower clusters are longer and more ornamental
29Giant Knotweed (Polygonum sachalinense) Large leaves give giant knotweed its common name elephant ear bambooGiant knotweed in early spring with last year’s dead stems
31Knotweed Invasion on Rivers Starts growth in April, full height by June (10-15 ft)Rhizomes spread 20 feet or more from parent and go as deep as 7 feetRoot and stem fragments as little as ½ inch can form new plantsSeasonal floods move and break up plants and rhizomes, allowing them to colonize exposed gravel bars and streamsidesPerennial - spreads mainly by fragmentsSections 5 cm or longer produce shootsExtensive rhizomatous mats - 5 meters deepAlso spreads in contaminated fillOutgrows and shades out natives and other plantsKnotweed rapidly spreads along rivers as fragments get moved by floods and grow into new clones downriver
32Scotch Broom (Cytisus scoparius) Evergreen shrub with green, ridged stemsFlowers bright yellow and pea-shapedLeaves small, oval, in threes or singleFlat seedpods with hairs on edges only, 1-2 inches longCONTROLPull young plants (mature plants with a weed wrench)Cut plants near ground level where the stem is more yellow than green in the dry season (July-September)Foliar herbicide application is most effective after full leaf development and before fall senescenceFor less dense sites, use selective treatment – cut stump (late spring), stem injection, basal/stem spray (in fall)From Europe, planted in gardens and for erosion control; introduced around the 1860’sSeeds remain viable up to 80 yearsSeeds emerge best when close to the surface (<1 inch); don’t usually germinate when buried over 4 inches, unless soil is disturbedSmall nodules on the roots harbor beneficial, N-fixing bacteria that allow broom to thrive even in poor soilsPlants began to degrade after 6 to 8 years and die by 10 to 15 years; older plants have a mix of dead, woody material and green growing parts (fire fuel)Oregon Dept of Agriculture estimates that it costs Oregon more than $40 million per year, mostly in lost forest production due to delays in re-establishing treesDisplaces native vegetation in meadows, riparian areas and floodplainsSeeds survive transport in river gravel and are moved during flooding or constructionAlso moved by vehicles, birds and animals
33Scotch Broom (Cytisus scoparius) Seeds survive transport in river gravel and are moved during flooding or constructionAlso moved by vehicles, birds and animalsSeeds emerge best when close to the surface (<1 inch); don’t usually germinate when buried over 4 inches, unless soil is disturbedSmall nodules on the roots harbor beneficial, N-fixing bacteria that allow broom to thrive even in poor soilsPlants began to degrade after 6 to 8 years and die by 10 to 15 years; older plants have a mix of dead, woody material and green growing parts (fire fuel)
34Scotch broom removal with weed wrenches Keep soil disturbance to a minimumPlan for long term management; at least ten years or more of monitoring siteClear thick stands with chainsaws, brush cutters, axes, machetes, loppersCut plants near ground level where the stem is more yellow than green; much more effective when done in the dry season (July-September)Key to success is to keep seeds from forming after initial clearingAfter using tractor-mowers or other tools, usually need to follow-up with more cutting or herbicidesWait until leaves have fully developed on re-sprouted stems before treating with herbicidesFoliar herbicide application is most effective after full leaf development and before fall senescenceFor less dense sites, use selective treatment – cut stump (late spring), stem injection, basal/stem spray (in fall)
35Butterfly Bush (Buddleia davidii) a large deciduous shrub 5' to 10' tall, produces large arching canescan grow 5' to 8' from the ground in a single seasonshowy flower clusters are purple or sometimes white, 4" to 10" long upright or nodding racemesblooms mid- to late summer until frostleaves a gray green to green above and white and fuzzy on the undersidestems pubescent and prominently angledopposite leaves simple, lanceolate, 4" to 10" long and 1" to 3" widemargins very finely toothednew stems are greenisholder stems develop gray-brown bark that exfoliates slightly in vertical shredsLeaves gray green above and white and fuzzy on the underside, finely toothed on marginsCan grow 5 to 8 feet in a single season
36Butterfly Bush (Buddleia davidii) Seedlings thrive in open sandy soilSpreads by seed in dry, sunny, open areas such as gravel bars, sandy riverbanksButterfly bush has invaded along the Tolt River
37Common Tansy (Tanacetum vulgare) Button-like flowers are clustered at top of plantLeaves are fern-like with sharply toothed edges and a strong odor
38Bittersweet Nightshade (Solanum dulcamara) Flower: Hanging clusters, each flower about 3/4 inch across, bright purple petals (occasionally white), yellow anthers, pretty, appearing all summer.Fruit: Hanging cluster of bright red, egg-shaped berries (3/8 to 1/2 inch long) ripen throughout the summer and fall.Leaf: Alternate, simple, entire margins, (2 to 4 inches) broadly ovate often with basal lobes, dark green above and lighter below, hairless.Form: Low climbing, scrambling, sprawling vine often draping low over trees and shrubs.Twig: Initially green, turning light brown, hollow pith, quite stiff, single bundle scar.Bark: Light brown, thin and lenticeled.Flowers from May to SeptemberFruit and seed production can be abundant
39Bittersweet Nightshade (Solanum dulcamara) Leaf: Alternate, simple, entire margins, (2 to 4 inches) broadly ovate often with basal lobes, dark green above and lighter below, hairless.Form: Low climbing, scrambling, sprawling vine often draping low over trees and shrubs.Twig: Initially green, turning light brown, hollow pith, quite stiff, single bundle scar.Bark: Light brown, thin and lenticeled.Flower: Hanging clusters, each flower about 3/4 inch across, bright purple petals (occasionally white), yellow anthers, pretty, appearing all summer.Fruit: Hanging cluster of bright red, egg-shaped berries (3/8 to 1/2 inch long) ripen throughout the summer and fall.Flowers from May to SeptemberFruit and seed production can be abundant
40Bittersweet Nightshade Bittersweet nightshade branches grow 3 to 9 ft or more each yearControlHand pulling of seedlings and repeated pulling on mature plantsSmothering plants to starve the roots: wood chip mulch with cardboard underneathHerbicide application: triclopyr or glyphosate; apply when plants are in full bloom
41Hedge Bindweed (Calystegia sepium) Hedge bindweed IDLarge bell-shaped flowers and broad heart-shaped leavesMostly seen growing along hillsides, drainage ditches, fencerows, and other poorly maintained areas. In the image to the left, notice the destructive effect hedge bindweed has on small plants. Leaf bracts are large and cover the flower's sepals.Also called wild morning glory; deep-rooted perennial in the Morningglory familyStem rotates in a circular patter until it makes contact with a solid structure (fence posts, other plants, etc.), then it wraps around the structure as it growsSpread by seed and root fragmentsSeed can persist in soil for up to 60 years, and roots can grow up to 30 feet deepCONTROLHand pulling of seedlings and repeated pulling on mature plantsSmothering plants to starve the roots (bindweed can survive underground for at least 3 years)Intensive cultivation (2 weeks) combined with competitive cropping; tilling to at least 4 inchesHerbicide application: triclopyr, possibly glyphosate (add a surfactant to better penetrate waxy cuticle); apply when plants are in full bloom
42Canada Thistle (Cirsium arvense) Aster family, PerennialDioeciousFlowers white to purpleReproduction primarily vegetative through creeping roots, some seedCanada thistle grows in deep, loose, cool soils, and is found throughout the United States. It grows to 4 feet tall and forms colonies. Multiple flowers branch from a single stem. The plant is dioecious, meaning that male and female flowers are borne on separate plants. However, because it spreads by creeping roots, it is possible for a colony of male plants to continue to spread.
43Canada Thistle (Cirsium arvense) University of WisconsinSpreads underground to form dense infestations in sunny fieldsDisking and plowing spreads Canada Thistle via regrowth from root fragments, so it is not recommended. Herbicides and/or regular mowing provide the best control.ControlsBiocontrol: one insect species available, but only provides limited controlFire: controlled spring burns will slow spreadMechanical: mowing can provide effective control if conducted at one month intervalsHerbicide: dicamba anytime in growing season; glyphosate past bud stage before frost; 2,4-D; MCPA when actively growingSpreads by seed to new sites
44Native Thistles Cirsium edule Cirsium brevistylum Congested terminal clusters of large round bright pink to red-purple flower heads at the end of each branch. Flower head spines are white wooly. Found in the cascades, coast mts. from Olympics south to south CaliforniaCirsium eduleCirsium brevistylum
45Poison Hemlock (Conium maculatum) Leaves ferny, parsley-likeStems round and hollow, with purplish blotchesAcutely toxic when ingested; causes skin irritationParsnip family (Apiaceae), 6 to 8 feet tallTiny white flowers in umbelsDistinctive purple splotches on hollow stems (mature plants)Leaves are fern like and have a musty odorHas a large white fleshy tap rootSeeds are paired, 1/8 inch long, brown, ribbed and concaveReproduces only by seedEntire plant is toxicGrows along streams and ditches throughout the United States.This weed is often mistaken for carrots or parsley because of its fern-like seedling.Sheep may be poisoned by as little as 4 ounces to 8 ounces of green leaves. Cattle that eat 10 ounces to 16 ounces may be affected. Smaller amounts may cause “crooked calves.”Control by digging young plants and pulling mature plants before they go to seed.Use gloves when handling.Large sites can be tilled, sprayed or even mowed to reduce seeding6 to 10 feet tall in 2nd year
46Poison Hemlock http://www.uwyo.edu/CES/WYOWEED/ Parsnip family (Apiaceae)6 to 8 feet tallTiny white flowers in umbelsDistinctive purple splotches on hollow stems (mature plants)Leaves are fern like and have a musty odorHas a large white fleshy tap rootSeeds are paired, 1/8 inch long, brown, ribbed and concaveReproduces only by seedEntire plant is toxicThis weed is often mistaken for carrots or parsley because of its fern-like seedling.All plant parts are poisonous, but fortunately livestock seldom eat the weed unless other feed is not available. Sheep may be poisoned by as little as 4 ounces to 8 ounces of green leaves. Cattle that eat 10 ounces to 16 ounces may be affected. Smaller amounts may cause “crooked calves.”Use gloves when handling.ControlsManual: Control by digging young plants and pulling mature plants before they go to seed.Biocontrol: hemlock moth (defoliates)Mechanical: mow prior to seed production; hand pull while wearing glovesChemical: MCPA or 2,4-D (if allowed on your site) at seedling to rosette stage; glyphosate before bolt; metsulfuron on growing plants; don’t graze in area for 3 weeks after spraying
47European Mountain-ash (Sorbus aucuparia) Leaf: Alternate, pinnately compound, 5 to 8 inches long, individual leaflets are serrated on their upper halves, 1 to 1 1/2 inches long, dull dark green above paler below.Flower: Showy clusters of small white flowers, clusters 3 to 5 inches across, appearing in late spring to early summer.Fruit: Clusters of bright deep orange small (3/8 inch in diameter) pomes, very showy, ripening in fall, persistent.Twig: Moderate to stout, pubescent early, becoming shiny gray-brown later in season, spur shoot present, leaf scars narrow, buds 3/8 to 1/2 inch long, reddish brown with long gray pubescences.Bark: When young, smooth with numerous lenticels, grayish brown, developing cracks, splits and scaly patches with age.Form: A small tree up to 40 feet tall, crown is initially elliptical but becoming wider with age.
48Native Mountain-ash (Sorbus sitchensis) Leaf: Alternate, pinnately compound (7 to 11 leaflets), alternate, and deciduous. Leaflets are elliptical, 1 to 3 inches long and serrated except near their base; green and smooth above and paler green below.Flower: Small white flowers borne in large, dense, flat-topped clusters; perfect and monoecious.Fruit: Small round pomes (1/4 to 1/2 inch diameter); red to orange.Twig: Stout and with many spur shoots; olive drab when young but turning greenish brown with age; light colored lenticelsBark: Thin and grayish- to brownish-green regardless of age.Form: An erect shrub or small tree, to 25 feet.
49English Holly (Ilex aquifolium) Tree 15 to 50 feet tall and 15 feet wideBark smooth and grayLeaves glossy, persistent, dark green, wavy and spinyFlowers are small and whiteBerries are bright red or orange and found in small bundles like the flowersNot sure if this one is in the watershed, but I wouldn’t be surprised to see it
50English or Atlantic Ivy (Hedera hibernica, H. helix) Ivy leaves are evergreen, lobed, dull green, with light veins
51English or Atlantic Ivy (Hedera hibernica, H. helix) mature ivy leaves are shiny green and not lobedumbrella-like clusters of greenish-white flowers in the fallblack, berry-like fruit in winter, seeds mature in spring
52Yellow Archangel Lamiastrum galeobdolon (a.k.a. Lamium) Currently on the State Monitor listKing County made a case for listing but not approved as a state noxious weedEscaping into urban and rural forestsPotential for being a huge problem in shady forestsSmall yellow mint-type flowers in leaf axilsSlivery markings on leaves of this popular garden plant make it easy to spot invading into shady forests
54Yellow Flag Iris (Iris pseudacorus) Class C Noxious Weed – Control Not RequiredYellow Flag Iris (Iris pseudacorus)Perennial monocot with showy yellow iris flowers in late spring-early summernative to Europe, Great Britain, North Africa, and Mediterranean regionSepals often streaked with brown to purple linesEmerging leaves similar to cattail but base of stem is flat in typical iris fashion (typha is round)Grows up to 1.5m tallFruit capsules up to 8cm long contain brown flattened corky seeds
55Yellow Flag Iris (Iris pseudacorus) Class C Noxious Weed – Control Not RequiredYellow Flag Iris (Iris pseudacorus)Invading a river bankOrnamental planted for its showy flower and tolerance to wet conditionsFound throughout King County in wetlands and waterbody edgesSpreads by thick rhizomes that overwinter. The rhizomes form dense mats that exclude other species, including aggressive plants like cattailForms dense, highly productive monocultures that spread radially from an underground stem (rhizome) systemTolerates prolonged soil saturation as well as dry soil conditions, but not deep shadeEvapotranspirates large quantities of soil moisture and potentially affects shallow groundwater hydrologyLarge biomass production clogs ditches and stream courses (blocks fish passage, increases flooding)Produces large quantities of pollen and can be a significant localized source of allergenYoung shoots
56Reed Canarygrass (Phalaris arundinacea) Tall rhizomatous grass, 3 to 6 feetSturdy, hollow stems, sometimes reddish near topLoose leaf sheathLeaf blades flat, no hairs, to ¾ inch wideLarge liguleLeaves come off stem at 45 degree angleLargeliguleA highly variable speciesrhizomatous perennial grass that can reach three to six feet in height.The sturdy, often hollow stems can be up to 1/2 inch in diameter, with some reddish coloration near the top.leaf blades are flat and hairless, 1/4 to 3/4 of an inch wide. Loose sheaths, large ligules.flowers are borne in panicles generally three to six inches in length.flowers in June and Julyspreads rapidly by rhizomes, will also root at nodes.Economic Importanceforms dense, highly productive monospecific stands in wetlands and riparian areas.outcompetes nativesareas that have existed as reed canarygrass monocultures for extended periods may have seed banks that are devoid of native specieslittle wildlife value. Few species eat the grass, and the stems grow too densely to provide adequate cover for small mammals and waterfowl.increases siltation along irrigation ditches and streamsPollen aggravates hay fever and allergiesplanted as a forage crop in some areas,an important component of lowland hay from Montana to Wisconsin (Hitchcock 1950).has been used for erosion control.The variegated-leaved variety picta L. is sometimes grown as an ornamentalGeographic Distributioncircumboreal species (Larson 1993).possibly native to North America, but European cultivars have been widely introducedno easy traits known for differentiating between the native plants and European cultivars.common throughout most of southern Alaska and Canada, as well as all but the southeastern portion of the U.S.Habitattypically occurs in soils that are saturated or nearly saturated for most of the growing season, but where standing water does not persist for extended periods.established stands can tolerate extended periods of inundation.Ideal conditions typically occur in roadside ditches, rights-of-way, river dikes and levees, shallow marshes, and meadows.Loose leaf sheath
57Reed Canarygrass Identification Flowers June-JulyFlowers on 3 to 7 inch long clusters high above leavesFlowers clusters are branched and compressed into a spike-type shapeReddish colored rhizomeForms dense stands, excluding other plants and filling in small waterways, blocking fish passage and increasing flooding
58Other Common Weeds and Garden Escapees Present but not Surveyed (too pervasive for control or not of immediate concern)Bull ThistleCommon FoxgloveHerb Robert/Robert’s GeraniumCommon St. JohnswortOxeye DaisyCreeping ButtercupHawksbeard, Hairy Cat’s Ear and Common DandelionOther Weeds and Garden Escapees
59Bull Thistle (Cirsium vulgare) Large, branched biennial; 2 to 3 feet tallLeaves pinnately lobedStiff spines on leaves and along ridged stemsWhite, woolly hair covers the stemsFlower heads 2 inches wide, very showy, bright magenta; vicious spines on bracts below flowersLarge spines on stems, leaves and under the flower head
60Bull Thistle (Cirsium vulgare) Horses consider flower heads a delicacy because of large amount of sugary nectarSpreads by seeds; move in wind on parachute like pappusControl by mowing or digging up crowns (use brush hook or similar tool to save time and disturb soil less)Horses will eat cut plants after they wilt (make sure to remove poisonous plants so they don’t get mixed in, like tansy ragwort)
62Herb Robert (a.k.a. Stinky Bob) (Geranium robertianum) Annual plant with distinctive unpleasant smell5 petaled flowers that bloom from early spring to late fallShade tolerant and can displace native wildflowersLow growing annualGeranium familyPink flowers throughout growing seasonDistinct odor when crushedStems red in sunny areasControlPull plants before they produce seed capsulesShallow roots make this plant easy to pull but seeds germinate all season so repeat visits to the same location are needed.
63Herb Robert (a.k.a. Stinky Bob) Annual plant with distinctive unpleasant smell5 petaled flowers that bloom from early spring to late fallShade tolerant and can displace native wildflowersLow growing annualGeranium familyPink flowers throughout growing seasonDistinct odor when crushedStems red in sunny areasControlPull plants before they produce seed capsulesHerb Robert (a.k.a. Stinky Bob)
64Stinky Bob InvasionForests near Skykomish are losing their native understory to stinky bob.
65St. Johnswort (Hypericum perforatum) Perennial herb 1 to 2 feet tall with stout taprootsFlat-topped clusters of golden yellow flowers 3/4 to 1 inch broadBlooms from midsummer to late fallFive yellow petals often have distinctive black dots around their edgesNumerous purple-tipped stamens project from other floral partsSeeds form in woody capsulesSpreads mostly by seed, also by short rhizomesSmall leaves appear to be perforated, opposite, elliptical, one inch longToxic both green and dryAnimals must consume the plants for 4 to 5 days or more before clinical signs are notedPasses from intestines to bloodstream; hypericin is “photo-active”, causes sunburn and cellular damageThe affected skin first becomes swollen and tender, then reddened. This occurs primarily on the lightly pigmented areas (pink or white skin), and on the areas of the body that receive more sunlight (head, neck, back).The skin can be burned to the point where large areas of skin peel off. This is extremely painful, and predisposes the animal to infection.Symptoms may take weeks to showGrows usually on dry, gravelly, or sandy soils in full sunshine
66St. Johnswort (Hypericum perforatum) Perennial herb 1 to 2 feet tall with stout taprootsFlat-topped clusters of golden yellow flowers 3/4 to 1 inch broadBlooms from midsummer to late fallFive yellow petals often have distinctive black dots around their edgesNumerous purple-tipped stamens project from other floral partsSeeds form in woody capsulesSpreads mostly by seed, also by short rhizomesSmall leaves appear to be perforated, opposite, elliptical, one inch longToxic both green and dryAnimals must consume the plants for 4 to 5 days or more before clinical signs are notedPasses from intestines to bloodstream; hypericin is “photo-active”, causes sunburn and cellular damageThe affected skin first becomes swollen and tender, then reddened. This occurs primarily on the lightly pigmented areas (pink or white skin), and on the areas of the body that receive more sunlight (head, neck, back).The skin can be burned to the point where large areas of skin peel off. This is extremely painful, and predisposes the animal to infection.Symptoms may take weeks to showGrows usually on dry, gravelly, or sandy soils in full sunshine
67Oxeye Daisy (Leucanthemum vulgare) Perennial daisy with white petals and yellow centersDaisy flowers grow singly on stems and are depressed in the centerFlowers June-AugustSpreads by rhizomes and seeds1-2 feet tallLeaves pinnately lobed or dividedForms dense populations in overgrazed pasturesNitrogen fertilizer will help reduce impact
69Creeping Buttercup (Ranunculus repens) Perennial herb, common invader in moist places and wet pasturesSpreads aggressively and rapidly as its elongate and prostrate stems root at the nodesRoots form dense, mat and are very difficult to dig upPlants are somewhat succulent and hairyBasal leaves have long stalks, divided into three main leaflets, that are further lobed and toothedLeaves typically have pale markings across the topBrilliant yellow flowers with shiny petalsFlowers have numerous stamens and pistils (like all buttercup family plants)Invades meadows, lawns, gardens and wetlands
70Tall Buttercup (Ranunculus acris) Erect perennial herb 1-3 feet tallStems are hairy, branching at the topLeaves are hairy, alternate, divided into narrow segments and usually three-cleftFlowers have five to seven shiny, oblong petals that are bright yellow, but may sometimes be cream-coloredSepals covered with hairs; lots of stamensCan be confused with sulfur cinquefoil and grow alongside itSpreads only by seedsMoist, poorly drained meadows and pasturesEntire plant is toxiccauses blisters and ulcers in mouth and intestinal tractspreads in hay but not toxic in dry haycan taint milk
71Hawksbeard (Crepis capillaris) Lack black-tipped hairs on flower budsLeaves are much more lobedNo stolonsHawksbeard flowers not clustered together at same heightCat’s Ear flowers single on top of stems, no hairs
72Cat’s Ear or False Dandelion (Hypochaeris radicata)
77Curly Dock (Rumex crispus) Buckwheat family (Polygonaceae)Tap-rooted perennialDark green alternate leavesSmall green flowers turn reddish brown at maturityReproduces by seed (30,000 seeds/plant); or by root cuttingsDock is especially common in wet meadows, along ditchbanks, and in waste areas. You may recognize it as “sour dock.” The broad leaves have crinkled or wavy margins.The reddish color of the two-foot to 3-foot tall mature seed stalks make it easy to recognize dock in a pasture or field.ControlsBiocontrol: grazing not effective; no biocontrol agents availableCultural: fertilize crops as neededMechanical: prevent seed set; hand pull or cultivate; mow to prevent floweringHerbicide: 2,4-D or dicamba before flower elongation; glyphosate at early heading; metsulfuron on young plantsReddish or greenish flowers in a long, slender, branching cluster at the top of a stem bearing leaves with very wavy margins
78Curly Dock (Rumex crispus) Buckwheat family, robust perennial up to 3 feet tallGrows from stout taprootLeaves are narrow, strap-like with crisp, curly edgesLower leaves are larger than upper leavesFlower clusters are long; Bloom April to MayThe green or brown flowers are each attached to a slender, drooping stalkThe fruits have three, heart-shaped wingsEuropean weed widely established in cultivated fields and pastures, waste areas
79Broadleaf Dock (Rumex obtusifolius) Perennial; like curly leaf dock but with broader leavesAnimals avoid this plant so pastures can get overrun if over-grazedBroadleaf dock (Rumex obtusifolius) habit has a large mound of foliage.Initially, plants form a rosette of foliage that lays prostrate to the ground. First year, Grows in a clump, 12 to 18 inches tall and wide.After the second year (broadleaf dock is a perennial), the plant grows further and can get 3 to 4 feet tall and wideBroadleaf dock (Rumex obtusifolius) foliage is large, broad, has a slight wavy margin, a long petiole, and often has a red to pink midrib.Control by digging with a shovel at least two inches down to remove crown or by annual cultivation (seeds survive for several years in the soil)New foliage emerges from the crown, tightly rolled and erect.Can grow 3 to 4 feet tall and wide
81(Symphytum X uplandicum or S. peregrinum) Russian Comfrey(Symphytum X uplandicum or S. peregrinum)From Europe; cultivated at times; a hybrid Russian Comfrey is the most weedy one, spreading by rootsRussian Comfrey is 3 to 6 feet tall with large, raspy leaves that are on stalks (not decurrent), amazingly persistent roots, flowers don’t set seed usuallyRussian Comfrey flowers are usually deep violet in bud and pale violet or lavender in flowerGarden comfrey is smaller, 2-4 feet tall, less raspy leaves, leaf stalk is decurrentFlowers are fully fertile, from violet to red to rosy, creamy-yellow or whiteSpreads by root fragments in compost; generally doesn’t invade but can be weedy and persistent
86Burdock (Arctium minus) Composite family; Biennial; Edible; Troublesome weed in fields, pastures and waste areasFirst year, very large, heart-shaped, irregularly lobed leaves, kind of like rhubarbSecond year, 2 to 4 foot stem with many large, egg-shaped lavendar-purple flower heads surrounded by hooks that cling to clothes or wool. Burdock blooms from July until SeptemberFlowers Flower head thistle-like, reddish-purple, egg-shaped, up to 2 x 3 cm. The bracts surrounding the flower head carry hooks that cling to clothes and wool.Fruit The 5-7 mm long achenes (seeds), with pappus ('thistle-down') up to 3.5 mm long, remain in the bur-like seed heads until they are caught on animals or clothing.Leaves Hollow-stalked, triangular basal leaves up to 40 cm long by 30 cm wide. Green and sparsely hairy on the upper surface, white and densely downy underneath. Base of leaves heart-shaped.Stems Sparsely to densely hairy, rarely hairless or mealy, grooved. Habitat Forest margins, scrub, creek beds, pasture, sheep-yards, gardens and waste places. CommentsYoung, cooked flowering stems can be used as a vegetable, and the small green shoots of young plants can be eaten. Burdock root has a reputation as a general herbal remedy.
88Creeping Woodsorrel (Oxalis corniculata) Life cycle: perennial, spreads by seed, rhizome, or stolons Habit: Small rounded clump, inches tall and wide; O. corniculata grows low and more prostrate, while O. stricta is taller and more mounded.Foliage: Palmately compound with 3 heart-shaped leaflets. Reminiscent of 4-leaf clover. Flower: Flowers are yellow with 5 petals and occur in an umbel (cluster). Seed or seedpods: Long, thin, angular, and pubescent (more so for O. corniculata).Cotyledon or seedling: Cotyledons are small and round. First true leaves are typical trifoliate and heart-shaped.Roots: Oxalis develop deep, thick taproots which make this weed difficult to hand pull from containers.O. stricta spreads by rhizomes while O. corniculata spreads by stolons.
90Orange Hawkweed (Hieracium aurantiacum) Class B Noxious WeedOrange Hawkweed (Hieracium aurantiacum)Flowers orange, in tight clustersStems leafless with black hairsFrom a few inches to 2 feet tallReproduces by seed and runnersBolts: May-JuneFlowers: Late May to Sep/OctSeeds: Late June to FallStems are leafless with stiff black hairsFrom a few inches to 2 feet tallReproduces by seed and runners
91Tall Hawkweed (Hieracium piloselloides) Class C Noxious Weed – Control RequiredTall Hawkweed (Hieracium piloselloides)Closely resembles yellow hawkweed, just taller with longer leaves
92Common Hawkweed (Hieracium lachenalii) Class C Noxious Weed – Control RequiredCommon Hawkweed (Hieracium lachenalii)Leaves coarsely toothedLeaves larger at base and smaller up the stemFlower heads more loosely clustered than yellow hawkweedNo stolonsBolts in MayFlowering May to AugustEasy to miss when it is growing mixed with other plantsCan spread to form dense infestations (then it’s easy to spot!)
93Purple Loosestrife (Lythrum salicaria) Class B Noxious WeedPurple Loosestrife (Lythrum salicaria)Key characteristics:perennial rhizomatous emergent with showy magenta flower spikesstems are square and branchedleaves opposite, long and narrowup to 2.5 million tiny seeds/plantflowers July and AugustPerennial with magenta flowering spikesRhizomatous perennial; reproduces by seed, roots andvegetative growthForms up to 2.5 million, pepper-size seeds per plantSeed banks build unnoticed for years, then underthe right conditions a widespread infestationmay suddenly emergeSeeds float on water and stick to animalsMature stands of purple loosestrife can live up to20 yearsFlowers July to September2.2 million seeds per mature plantoriginally introduced as ballast in ships along the NE seaboarddistributed as a garden ornamentalUsually associated with moist or marshy areasAlters wetland ecosystems by replacing native andbeneficial plantsDense infestations can impede water flowDisplaces nesting habitat for waterfowl, fur-bearinganimals and birdsAgriculture is impacted by a loss of wild meadows,hay meadows and wetland pasturesDistributionOccurs in freshwater and brackish wetlandsFound on lakes and waterways throughoutKing CountySometimes cultivated as a garden ornamental
94Purple Loosestrife (Lythrum salicaria) Class B Noxious WeedPurple Loosestrife (Lythrum salicaria)Rhizomatous perennial; reproduces by seed, roots and vegetative growthForms up to 2.5 million, pepper-size seeds per plantSeed banks build unnoticed for years then emerge when soils are exposedSeeds float on water and stick to animalsUsually associated with moist or marshy areasAlters wetland ecosystems by replacing native and beneficial plants (will out-compete cattails)Dense infestations can impede water flowCauses flush of phosphorus in fall instead of over winter and in spring as with nativesCan accelerate eutrophication of downstream water bodiesDisplaces nesting habitat for waterfowl, fur-bearing animals and birdsAquatic insects are smaller when grown in loosestrife thickets than in native wetland plant communitiesDistributionOccurs in freshwater and brackish wetlandsFound on lakes and waterways throughout King CountySometimes cultivated as a garden ornamental
95Garden Loosestrife (Lysimachia vulgaris) Class B Noxious WeedGarden Loosestrife (Lysimachia vulgaris)Sepals have distinct orange marginsPerennialFlowersYellow, primrose-likeClustered near top of the plantLeavesLance-shapedOpposite or whorledDotted with black or orange glandsYellow, primrose-like flowers clustered near top of the plant
96Garden Loosestrife (Lysimachia vulgaris) Class B Noxious WeedGarden Loosestrife (Lysimachia vulgaris)Flowers - bright yellow, 5-petaled with darker centers.Flowers are found in clusters near the top of the plant.Stems and leaves are softly hairy, opposite or whorledRhizomatous perennialReaches 5 feet tallSpreads by seeds and short rhizomes. Flowers in JulyIntroduced as a garden ornamentalShares wetland habitat with purple loosestrife, where it appears capable of outcompeting it.Marymoor Park on Lake Sammamish has the heart of the infestation in our area, but also dense along the Sammamish Slough and the shore of the lake. Also patches along Lake Washington shoreline and wetlands.Only known large infest outside of Lake Samm/WA is near the Snoqualmie River in Rutherford Slough, probably spread from a former nursery.No biocontrol available. In primrose family; too many native cousins here that would also be attacked by insects that eat this plant in its native range.
97Policeman’s Helmet (Impatiens glandulifera) Class B Noxious WeedPoliceman’s Helmet (Impatiens glandulifera)Class B Noxious weedHerbaceous annual, ftLeavesOblong/ovate, oppositeMargins are sharply serrateFlowerWhite, pink or purple; June to SepemberIrregular, 5 petals (2 fused)Escapes gardens into ravines, streamsides, parks, woodlandsAnnual with fleshy, reddish stems, ft tall, flowers resemble English policeman’s helmet, vary in color from white to dark pink-purple
98Policeman’s Helmet (Impatiens glandulifera) Class B Noxious WeedPoliceman’s Helmet (Impatiens glandulifera)Emerges: April to MayFlowers: Late May to SeptemberSeeds: August to OctoberSpreads rapidly by seed if not controlledNative to India, western HimalayasCan grow over 10’ tallProduces seeds per plantSeeds are ejected 15 to 20 feetCompetes with native plants for pollinators,reducing the seed set of native plantsConsidered one of the ‘Top 20” invasivesin the United KingdomOften found invading along creeksCan grow to 10 feet tall in one season
99Sulfur Cinquefoil (Potentilla recta) Class B Noxious WeedSulfur Cinquefoil (Potentilla recta)Rose family, Perennial, 1-3 ft. tallwoody rootstock5-7 palmate leaflets, Flowers pale yellowFlowers June-JulyForms single species stands in rangelands, pastures, roadsides and fields.Regenerates annually from new shoots emerging from edges of the root mass.Unpalatable to livestock and wildlife.Meadows, pastureseast of Redmond and Covington/Maple Valley areaRoots are woody and deep so control methods need to be repeatedDigging up roots will work but follow-up is needed because roots will re-sproutMost effective chemicals: metsulfuron, triclopyr, 2,4-D ester (Crossbow best, Garlon next best)Timing: 2,4-D ester alone in rosette to bud stage (April-May)2,4-D+dicamba: spring and fall (Weedmaster only partly effective, need repeat apps)Glyphosate (where there’s no grass): summer/fall – need good surfactantDigging: works but need repeat treatmentsMowing: does not work, makes root crown grow and stems flower shorter
100Dalmatian Toadflax (Linaria dalmatica) Class B Noxious WeedDalmatian Toadflax (Linaria dalmatica)Leaves bluish-green with waxy coating, heart-shapedFlowers bright yellow tinged with orange, like snapdragon flowersBolts: April-JuneFlowers: May-SeptSeeds: Aug-SeptScrophulariaceaePerennial herb with erect stems up to 3-4 ft. tallFlowers from May to AugustRoots are deep and extensive and can break off easily near the surfaceLeaves alternate, bluish-green with waxy coating, heart-shaped, clasping the stem and are rubbery in textureFlowers are bright yellow, tinged with orange, and resemble snapdragon flowers
101Yellow Toadflax (Linaria vulgaris) Class C Noxious Weed – Control Not RequiredYellow Toadflax (Linaria vulgaris)Perennial, 1 to 2.5 feet tallFlowers yellow, smaller than Dalmatian flowersMay to SeptemberLeaves: Small, narrow, linear, pale greenRoads, railroads, industrial areas, trails, ornamental plantingsCONTROLDigging small patchesNot mowingDicamba: before bloom stage, repeat as neededChlorsulfuron (Telar): bud to bloom stage, use penetrating surfactant, will suppress onlyGlyphosate: actively growing, get complete coverage
102Gorse (Ulex europaeus) Class B Noxious WeedGorse (Ulex europaeus)Evergreen with large spinesYellow, fragrant pea flowersFlowers in early springFire hazardBrought from Ireland to Oregon in the 1800’sForms extensive stands in coastal and open areasBudding: Feb-MarchFlowers: March-MaySeeds: June-July
104Old Man’s Beard (Clematis vitalba) Class C Noxious Weed – Control Not RequiredOld Man’s Beard (Clematis vitalba)Climbing, deciduous vineCompound leaves, composed of 5 leaflets (1 to 3 leaflets on seedlings)Creamy white, sweet smelling flowers with four petalsFeathery seed heads account for the common name of old man’s beardOlder vines have stringy, furrowed bark, which is pale brown in color.Native of Europe and southwest AsiaVigorously climbs over other vegetation and structures, and can be invasive along roadsides, river banks, forest edges and fencelines, and in gardens and disturbed forestsHas become a major threat to native forests, covering entire trees and preventing regeneration in forest gaps
105Old Man’s Beard or Wild Clematis Class C Noxious Weed – Control Not RequiredOld Man’s Beard or Wild ClematisNative of Europe and southwest AsiaVigorously climbs over other vegetation and structures, and can be invasive along roadsides, river banks, forest edges and fencelines, and in gardens and disturbed forestsHas become a major threat to native forests, covering entire trees and preventing regeneration in forest gapsOld Man’s Beard on trees in Ravenna ParkOld Man’s Beard covering trees at Magnuson Park
106King County Noxious Weed Control Program Website Weed Photo Page:Search by Common Name or Latin NameClick thumbnail picture of plant
107Sasha Shaw King County Noxious Weed Program 201 South Jackson St, Suite 600 Seattle, WA