Invasive Weeds on the Middle Fork Snoqualmie

Invasive Weeds on the Middle Fork Snoqualmie
Sasha Shaw Education Specialist King County Noxious Weed Program

Agenda Weed Definitions Middle Fork Weed Priorities
Priority Weeds Present in the Watershed Class A and B Noxious Weeds Other Priority Invasive Weeds Other Widespread Weeds and Lower Priority Plants Present but not Surveyed Noxious Weeds Threatening to Invade

What is an Invasive Weed?
Introduced / non-native Ability to out-compete native plants Lack of predators or natural controls Ability to modify local ecology Aggressive ability to reproduce Rapidly multiply to dominate a site and are extremely difficult to control Introduced to Washington either accidentally or on purpose by humans Evolved 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 homeland Aquatic 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 US Heavily planted: of the 124 state noxious weeds, 61 were introduced as ornamentals Multiple forms of reproduction: many seeds, vegetative growth, fragments Rapid growth Easily transported: burs, winged seeds Invasive knotweed is one of the toughest plants to control and damages some of the highest quality habitats

What is a Noxious Weed? Non-native plant that impacts agriculture, wildlife, human health, land values or natural resources Defined and regulated by state law (RCW 17.10) county lists are chosen from the state list regulated in parts of the state where they have limited distribution

What are the Weed Classes?
Class A Weeds – new invaders, control required statewide, still a chance to eradicate Class B and C Designates – control required in King County, still have a chance to stop them from getting established Non-Designates and Weeds of Concern – widespread invasive weeds in King County, control not required but definitely a good idea whenever possible!

Middle Fork Snoqualmie Weed Priorities
King County Noxious Weeds Class A’s, B-designates, and C-selects Non-designates and Weeds of Concern that are limited in distribution and still controllable Non-native species newly introduced or not previously reported in the valley Excluded from the survey: species that are already pervasive in the valley and unlikely to be controlled valley-wide

Middle Fork Snoqualmie Weed Surveys Completed 2005 and 2006
Roadsides (10 ft in on both sides) Farther in where disturbance or weed infestations were observed Disturbed Sites Quarries, cut banks, logging landings Camping sites, pullouts, trailheads, parking lots Open talus fields, stream crossings River by raft and river bars on foot

Priority Weeds Identified in the Middle Fork Valley
Himalayan and Evergreen Blackberry Bohemian Knotweed Scotch Broom Reed Canary Grass English Holly English Ivy Butterfly Bush Tansy Ragwort* Yellow Hawkweed* Canada Thistle Hedge Bindweed Common Tansy Yellow Archangel Yellow Flag Iris European Mountain-Ash Spotted Knapweed* Bittersweet Nightshade Poison-hemlock Listed in order of total area found. Weeds with * are designated for control in King County.

Class A and B Noxious Weeds
(Please notify the county noxious weed program if these are found)

Tansy Ragwort (Senecio jacobaea)
Class B Noxious Weed Tansy Ragwort (Senecio jacobaea) Flowering stems are 1-6 ft tall with clusters of yellow, daisy flowers First year rosettes have round-lobed leaves, reddish stems A biennial plant; rosettes the first year and in the spring; flowering stems the following year and in the summer Flowers June to October. Seeds are viable for 10 to 16 years.

Tansy Ragwort (Senecio jacobaea)
A biennial plant; rosettes the first year and in the spring; flowering stems the following year and in the summer Controls Manual: Hand pull or dig up small infestations. Biocontrols: Cinnabar moth, ragwort flea beetle Mechanical: 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.

Yellow Hawkweed (Hieracium caespitosum)
Flowers: Yellow, in tight clusters Leaves: Hairy on top and bottom, glandular and stellate hairs Roots: stoloniferous, rhizomatous

Non-native Hawkweeds Stiff hairs on stems, leaves
Basal rosette of spatula shaped leaves Small flowers, often in tight clusters near tops of stems Flower buds and bracts covered with black hairs Stolons Leaves mostly broader at tip than at base, 4-6 inches long Narrow at base to a short petiole Leaves usually hairy Stems progressively less leafy from bottom to top Each rosette usually produces 1-8 flower stems, 2-36 inches tall Milky sap Flowers borne in clusters of 5-30 near top of stem Heads ½ to ¾ inch wide, seeds dandelion-like but shorter Black hairs on flower buds

Yellow Hawkweed (Hieracium caespitosum)
Rosettes: March-April Bolting: April-early June Flowers: May-July Seeding: July to September

Native White Hawkweed: (Hieracium albiflorum)

Spotted Knapweed (Centaurea stoebe)
Grows feet tall, perennial Pink to purple flowers, on the tips of stem branches Floral bracts tipped with dark fringe Bolting: April to July Flowering: May to October Seeding: August to October Reproduces by seed Black tips on the bracts, giving a spotted appearance Slender, wiry branches It 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. Controls Biocontrol: thirteen insect species; cattle, sheep or goat grazing useful in reduction Digging: best when done earlier in season when soil is moist Mechanical: cutting or mowing prior to seed set provides reduction but not elimination Herbicide: 2,4-D at early stem elongation, glyphosate when mostly in bud

Spotted Knapweed Closeups

Other Priority Invasive Weeds in the MF

Himalayan 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 shade Form impenetrable thickets (lowering plant diversity, providing habitat for rats, etc.) In less than 2 years, one cutting can produce a 15 foot diameter thicket Out-compete low growing natives and can prevent establishment of trees such as Douglas fir, pine and oak Limits movement of large animals between forest and small meadows for grazing A poor replacement for a diverse native forest understory or riparian floodplain Two widespread, non-native blackberries: Himalayan blackberry (Rubus armeniacus or R. discolor) & evergreen blackberry (Rubus laciniatus); both very invasive From Western Europe; introduced to US around 1885, naturalized by 1945

Himalayan Blackberry (Rubus armeniacus, R. discolor)
Robust, sprawling shrub with canes to 9 feet tall, feet long Large thorns on stems, leaves and leaf stalks Leaves with 5 large, oval, toothed leaflets White to light pink flowers and large, black berries The 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.

Evergreen Blackberry (Rubus laciniatus)
Leaves are lacy, deeply toothed Similar growth form and invasiveness to Himalayan blackberry Erect, 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 underside Stems are stout, heavily ribbed, purplish-red, armed with heavy recurved prickles Flowers are white to pink, appear in June, berries are black As 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.

Good Guy Look-Alike: Native Trailing Blackberry (Rubus ursinus)
Low-growing, trailing, often found in wooded areas Stems are thin, green when young, brown when mature Densely covered with smallish thorns Leaves are evergreen, with 3 leaflets, green on top, lighter green underneath Leaf: 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.

Bohemian Knotweed (Polygonum bohemicum)
Perennials with creeping rhizomes Introduced as ornamentals; used like bamboo Habitat: disturbed, riparian, wetland Impacts: Dense colonies, exclude native vegetation

Hollow, upright, bamboo like stems often reddish or red-speckled

Typical stand of Bohemian knotweed
naturally occurring hybrid between the other two most common type of knotweed found in the Pacific Northwest medium tall (8 to 12 feet), mixed leaf shapes introduced as an ornamental separately most 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

Japanese Knotweed (Polygonum cuspidatum)
Smaller than the others (6 feet usually) Leaf bases are flat, not heart-shaped Most clones in US are female (will have seeds later in season) Flower clusters are longer and more ornamental

Giant Knotweed (Polygonum sachalinense)
Large leaves give giant knotweed its common name elephant ear bamboo Giant knotweed in early spring with last year’s dead stems

Bohemian knotweed hybrid with seeds

Knotweed 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 feet Root and stem fragments as little as ½ inch can form new plants Seasonal floods move and break up plants and rhizomes, allowing them to colonize exposed gravel bars and streamsides Perennial - spreads mainly by fragments Sections 5 cm or longer produce shoots Extensive rhizomatous mats - 5 meters deep Also spreads in contaminated fill Outgrows and shades out natives and other plants Knotweed rapidly spreads along rivers as fragments get moved by floods and grow into new clones downriver

Scotch Broom (Cytisus scoparius)
Evergreen shrub with green, ridged stems Flowers bright yellow and pea-shaped Leaves small, oval, in threes or single Flat seedpods with hairs on edges only, 1-2 inches long CONTROL Pull 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 senescence For 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’s Seeds remain viable up to 80 years Seeds emerge best when close to the surface (<1 inch); don’t usually germinate when buried over 4 inches, unless soil is disturbed Small nodules on the roots harbor beneficial, N-fixing bacteria that allow broom to thrive even in poor soils Plants 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 trees Displaces native vegetation in meadows, riparian areas and floodplains Seeds survive transport in river gravel and are moved during flooding or construction Also moved by vehicles, birds and animals

Scotch Broom (Cytisus scoparius)
Seeds survive transport in river gravel and are moved during flooding or construction Also moved by vehicles, birds and animals Seeds emerge best when close to the surface (<1 inch); don’t usually germinate when buried over 4 inches, unless soil is disturbed Small nodules on the roots harbor beneficial, N-fixing bacteria that allow broom to thrive even in poor soils Plants 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)

Scotch broom removal with weed wrenches
Keep soil disturbance to a minimum Plan for long term management; at least ten years or more of monitoring site Clear thick stands with chainsaws, brush cutters, axes, machetes, loppers Cut 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 clearing After using tractor-mowers or other tools, usually need to follow-up with more cutting or herbicides Wait until leaves have fully developed on re-sprouted stems before treating with herbicides Foliar herbicide application is most effective after full leaf development and before fall senescence For less dense sites, use selective treatment – cut stump (late spring), stem injection, basal/stem spray (in fall)

Butterfly Bush (Buddleia davidii)
a large deciduous shrub 5' to 10' tall, produces large arching canes can grow 5' to 8' from the ground in a single season showy flower clusters are purple or sometimes white, 4" to 10" long upright or nodding racemes blooms mid- to late summer until frost leaves a gray green to green above and white and fuzzy on the underside stems pubescent and prominently angled opposite leaves simple, lanceolate, 4" to 10" long and 1" to 3" wide margins very finely toothed new stems are greenish older stems develop gray-brown bark that exfoliates slightly in vertical shreds Leaves gray green above and white and fuzzy on the underside, finely toothed on margins Can grow 5 to 8 feet in a single season

Butterfly Bush (Buddleia davidii)
Seedlings thrive in open sandy soil Spreads by seed in dry, sunny, open areas such as gravel bars, sandy riverbanks Butterfly bush has invaded along the Tolt River

Common Tansy (Tanacetum vulgare)
Button-like flowers are clustered at top of plant Leaves are fern-like with sharply toothed edges and a strong odor

Bittersweet 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 September Fruit and seed production can be abundant

Bittersweet 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 September Fruit and seed production can be abundant

Bittersweet Nightshade
Bittersweet nightshade branches grow 3 to 9 ft or more each year Control Hand pulling of seedlings and repeated pulling on mature plants Smothering plants to starve the roots: wood chip mulch with cardboard underneath Herbicide application: triclopyr or glyphosate; apply when plants are in full bloom

Hedge Bindweed (Calystegia sepium)
Hedge bindweed ID Large bell-shaped flowers and broad heart-shaped leaves Mostly 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 family Stem 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 grows Spread by seed and root fragments Seed can persist in soil for up to 60 years, and roots can grow up to 30 feet deep CONTROL Hand pulling of seedlings and repeated pulling on mature plants Smothering 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 inches Herbicide application: triclopyr, possibly glyphosate (add a surfactant to better penetrate waxy cuticle); apply when plants are in full bloom

Canada Thistle (Cirsium arvense)
Aster family, Perennial Dioecious Flowers white to purple Reproduction primarily vegetative through creeping roots, some seed Canada 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.

Canada Thistle (Cirsium arvense)
University of Wisconsin Spreads underground to form dense infestations in sunny fields Disking and plowing spreads Canada Thistle via regrowth from root fragments, so it is not recommended. Herbicides and/or regular mowing provide the best control. Controls Biocontrol: one insect species available, but only provides limited control Fire: controlled spring burns will slow spread Mechanical: mowing can provide effective control if conducted at one month intervals Herbicide: dicamba anytime in growing season; glyphosate past bud stage before frost; 2,4-D; MCPA when actively growing Spreads by seed to new sites

Native 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 California Cirsium edule Cirsium brevistylum

Poison Hemlock (Conium maculatum)
Leaves ferny, parsley-like Stems round and hollow, with purplish blotches Acutely toxic when ingested; causes skin irritation Parsnip family (Apiaceae), 6 to 8 feet tall Tiny white flowers in umbels Distinctive purple splotches on hollow stems (mature plants) Leaves are fern like and have a musty odor Has a large white fleshy tap root Seeds are paired, 1/8 inch long, brown, ribbed and concave Reproduces only by seed Entire plant is toxic Grows 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 seeding 6 to 10 feet tall in 2nd year

Poison Hemlock http://www.uwyo.edu/CES/WYOWEED/
Parsnip family (Apiaceae) 6 to 8 feet tall Tiny white flowers in umbels Distinctive purple splotches on hollow stems (mature plants) Leaves are fern like and have a musty odor Has a large white fleshy tap root Seeds are paired, 1/8 inch long, brown, ribbed and concave Reproduces only by seed Entire plant is toxic This 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. Controls Manual: 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 gloves Chemical: 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

European 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.

Native 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 lenticels Bark: Thin and grayish- to brownish-green regardless of age. Form: An erect shrub or small tree, to 25 feet.

English Holly (Ilex aquifolium)
Tree 15 to 50 feet tall and 15 feet wide Bark smooth and gray Leaves glossy, persistent, dark green, wavy and spiny Flowers are small and white Berries are bright red or orange and found in small bundles like the flowers Not sure if this one is in the watershed, but I wouldn’t be surprised to see it

English or Atlantic Ivy (Hedera hibernica, H. helix)
Ivy leaves are evergreen, lobed, dull green, with light veins

English or Atlantic Ivy (Hedera hibernica, H. helix)
mature ivy leaves are shiny green and not lobed umbrella-like clusters of greenish-white flowers in the fall black, berry-like fruit in winter, seeds mature in spring

Yellow Archangel Lamiastrum galeobdolon (a.k.a. Lamium)
Currently on the State Monitor list King County made a case for listing but not approved as a state noxious weed Escaping into urban and rural forests Potential for being a huge problem in shady forests Small yellow mint-type flowers in leaf axils Slivery markings on leaves of this popular garden plant make it easy to spot invading into shady forests

Yellow Archangel: Big Finn Hill Park

Yellow Flag Iris (Iris pseudacorus)
Class C Noxious Weed – Control Not Required Yellow Flag Iris (Iris pseudacorus) Perennial monocot with showy yellow iris flowers in late spring-early summer native to Europe, Great Britain, North Africa, and Mediterranean region Sepals often streaked with brown to purple lines Emerging leaves similar to cattail but base of stem is flat in typical iris fashion (typha is round) Grows up to 1.5m tall Fruit capsules up to 8cm long contain brown flattened corky seeds

Yellow Flag Iris (Iris pseudacorus)
Class C Noxious Weed – Control Not Required Yellow Flag Iris (Iris pseudacorus) Invading a river bank Ornamental planted for its showy flower and tolerance to wet conditions Found throughout King County in wetlands and waterbody edges Spreads by thick rhizomes that overwinter. The rhizomes form dense mats that exclude other species, including aggressive plants like cattail Forms dense, highly productive monocultures that spread radially from an underground stem (rhizome) system Tolerates prolonged soil saturation as well as dry soil conditions, but not deep shade Evapotranspirates large quantities of soil moisture and potentially affects shallow groundwater hydrology Large 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 allergen Young shoots

Reed Canarygrass (Phalaris arundinacea)
Tall rhizomatous grass, 3 to 6 feet Sturdy, hollow stems, sometimes reddish near top Loose leaf sheath Leaf blades flat, no hairs, to ¾ inch wide Large ligule Leaves come off stem at 45 degree angle Large ligule A highly variable species rhizomatous 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 July spreads rapidly by rhizomes, will also root at nodes. Economic Importance forms dense, highly productive monospecific stands in wetlands and riparian areas. outcompetes natives areas that have existed as reed canarygrass monocultures for extended periods may have seed banks that are devoid of native species little 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 streams Pollen aggravates hay fever and allergies planted 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 ornamental Geographic Distribution circumboreal species (Larson 1993). possibly native to North America, but European cultivars have been widely introduced no 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. Habitat typically 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

Reed Canarygrass Identification
Flowers June-July Flowers on 3 to 7 inch long clusters high above leaves Flowers clusters are branched and compressed into a spike-type shape Reddish colored rhizome Forms dense stands, excluding other plants and filling in small waterways, blocking fish passage and increasing flooding

Other Common Weeds and Garden Escapees Present but not Surveyed (too pervasive for control or not of immediate concern) Bull Thistle Common Foxglove Herb Robert/Robert’s Geranium Common St. Johnswort Oxeye Daisy Creeping Buttercup Hawksbeard, Hairy Cat’s Ear and Common Dandelion Other Weeds and Garden Escapees

Bull Thistle (Cirsium vulgare)
Large, branched biennial; 2 to 3 feet tall Leaves pinnately lobed Stiff spines on leaves and along ridged stems White, woolly hair covers the stems Flower heads 2 inches wide, very showy, bright magenta; vicious spines on bracts below flowers Large spines on stems, leaves and under the flower head

Bull Thistle (Cirsium vulgare)
Horses consider flower heads a delicacy because of large amount of sugary nectar Spreads by seeds; move in wind on parachute like pappus Control 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)

Foxglove (Digitalis purpurea)

Herb Robert (a.k.a. Stinky Bob) (Geranium robertianum)
Annual plant with distinctive unpleasant smell 5 petaled flowers that bloom from early spring to late fall Shade tolerant and can displace native wildflowers Low growing annual Geranium family Pink flowers throughout growing season Distinct odor when crushed Stems red in sunny areas Control Pull plants before they produce seed capsules Shallow roots make this plant easy to pull but seeds germinate all season so repeat visits to the same location are needed.

Herb Robert (a.k.a. Stinky Bob)
Annual plant with distinctive unpleasant smell 5 petaled flowers that bloom from early spring to late fall Shade tolerant and can displace native wildflowers Low growing annual Geranium family Pink flowers throughout growing season Distinct odor when crushed Stems red in sunny areas Control Pull plants before they produce seed capsules Herb Robert (a.k.a. Stinky Bob)

Stinky Bob Invasion Forests near Skykomish are losing their native understory to stinky bob.

St. Johnswort (Hypericum perforatum)
Perennial herb 1 to 2 feet tall with stout taproots Flat-topped clusters of golden yellow flowers 3/4 to 1 inch broad Blooms from midsummer to late fall Five yellow petals often have distinctive black dots around their edges Numerous purple-tipped stamens project from other floral parts Seeds form in woody capsules Spreads mostly by seed, also by short rhizomes Small leaves appear to be perforated, opposite, elliptical, one inch long Toxic both green and dry Animals must consume the plants for 4 to 5 days or more before clinical signs are noted Passes from intestines to bloodstream; hypericin is “photo-active”, causes sunburn and cellular damage The 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 show Grows usually on dry, gravelly, or sandy soils in full sunshine

Oxeye Daisy (Leucanthemum vulgare)
Perennial daisy with white petals and yellow centers Daisy flowers grow singly on stems and are depressed in the center Flowers June-August Spreads by rhizomes and seeds 1-2 feet tall Leaves pinnately lobed or divided Forms dense populations in overgrazed pastures Nitrogen fertilizer will help reduce impact

Oxeye Daisy (Leucanthemum vulgare)

Creeping Buttercup (Ranunculus repens)
Perennial herb, common invader in moist places and wet pastures Spreads aggressively and rapidly as its elongate and prostrate stems root at the nodes Roots form dense, mat and are very difficult to dig up Plants are somewhat succulent and hairy Basal leaves have long stalks, divided into three main leaflets, that are further lobed and toothed Leaves typically have pale markings across the top Brilliant yellow flowers with shiny petals Flowers have numerous stamens and pistils (like all buttercup family plants) Invades meadows, lawns, gardens and wetlands

Tall Buttercup (Ranunculus acris)
Erect perennial herb 1-3 feet tall Stems are hairy, branching at the top Leaves are hairy, alternate, divided into narrow segments and usually three-cleft Flowers have five to seven shiny, oblong petals that are bright yellow, but may sometimes be cream-colored Sepals covered with hairs; lots of stamens Can be confused with sulfur cinquefoil and grow alongside it Spreads only by seeds Moist, poorly drained meadows and pastures Entire plant is toxic causes blisters and ulcers in mouth and intestinal tract spreads in hay but not toxic in dry hay can taint milk

Hawksbeard (Crepis capillaris)
Lack black-tipped hairs on flower buds Leaves are much more lobed No stolons Hawksbeard flowers not clustered together at same height Cat’s Ear flowers single on top of stems, no hairs

Cat’s Ear or False Dandelion (Hypochaeris radicata)

Nipplewort (Lapsana communis)

Wall Lettuce (Lactuca muralis)

Prickly Lettuce (Lactuca serriola)

Woodland Groundsel (Senecio sylvaticus)

Curly Dock (Rumex crispus)
Buckwheat family (Polygonaceae) Tap-rooted perennial Dark green alternate leaves Small green flowers turn reddish brown at maturity Reproduces by seed (30,000 seeds/plant); or by root cuttings Dock 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. Controls Biocontrol: grazing not effective; no biocontrol agents available Cultural: fertilize crops as needed Mechanical: prevent seed set; hand pull or cultivate; mow to prevent flowering Herbicide: 2,4-D or dicamba before flower elongation; glyphosate at early heading; metsulfuron on young plants Reddish or greenish flowers in a long, slender, branching cluster at the top of a stem bearing leaves with very wavy margins

Curly Dock (Rumex crispus)
Buckwheat family, robust perennial up to 3 feet tall Grows from stout taproot Leaves are narrow, strap-like with crisp, curly edges Lower leaves are larger than upper leaves Flower clusters are long; Bloom April to May The green or brown flowers are each attached to a slender, drooping stalk The fruits have three, heart-shaped wings European weed widely established in cultivated fields and pastures, waste areas

Broadleaf Dock (Rumex obtusifolius)
Perennial; like curly leaf dock but with broader leaves Animals avoid this plant so pastures can get overrun if over-grazed Broadleaf 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 wide Broadleaf 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

Periwinkle (Vinca minor)

(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 roots Russian 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 usually Russian Comfrey flowers are usually deep violet in bud and pale violet or lavender in flower Garden comfrey is smaller, 2-4 feet tall, less raspy leaves, leaf stalk is decurrent Flowers are fully fertile, from violet to red to rosy, creamy-yellow or white Spreads by root fragments in compost; generally doesn’t invade but can be weedy and persistent

Russian Comfrey

Native Plant Look Alike: Tall Bluebells (Mertensia paniculata)

Queen Anne’s Lace (Daucus carota)

Burdock (Arctium minus)
Composite family; Biennial; Edible; Troublesome weed in fields, pastures and waste areas First year, very large, heart-shaped, irregularly lobed leaves, kind of like rhubarb Second 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 September Flowers 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. Comments Young, 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.

Devil’s Beggartick (Bidens frondosa)

Creeping 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.

Noxious Weeds threatening to Invade (present nearby)
Purple Loosestrife (wetlands, rivers in area) Garden Loosestrife (on Snoqualmie River) Policeman’s Helmet (garden sites) Gorse (forests, fields) Orange Hawkweed (meadows, gardens, roads) Common Hawkweed (roadsides) Sulfur Cinquefoil (roadsides) Dalmatian Toadflax (roadsides) Yellow Toadflax (roads and trails) Old Man’s Beard (forest edges, trails)

Orange Hawkweed (Hieracium aurantiacum)
Class B Noxious Weed Orange Hawkweed (Hieracium aurantiacum) Flowers orange, in tight clusters Stems leafless with black hairs From a few inches to 2 feet tall Reproduces by seed and runners Bolts: May-June Flowers: Late May to Sep/Oct Seeds: Late June to Fall Stems are leafless with stiff black hairs From a few inches to 2 feet tall Reproduces by seed and runners

Tall Hawkweed (Hieracium piloselloides)
Class C Noxious Weed – Control Required Tall Hawkweed (Hieracium piloselloides) Closely resembles yellow hawkweed, just taller with longer leaves

Common Hawkweed (Hieracium lachenalii)
Class C Noxious Weed – Control Required Common Hawkweed (Hieracium lachenalii) Leaves coarsely toothed Leaves larger at base and smaller up the stem Flower heads more loosely clustered than yellow hawkweed No stolons Bolts in May Flowering May to August Easy to miss when it is growing mixed with other plants Can spread to form dense infestations (then it’s easy to spot!)

Purple Loosestrife (Lythrum salicaria)
Class B Noxious Weed Purple Loosestrife (Lythrum salicaria) Key characteristics: perennial rhizomatous emergent with showy magenta flower spikes stems are square and branched leaves opposite, long and narrow up to 2.5 million tiny seeds/plant flowers July and August Perennial with magenta flowering spikes Rhizomatous perennial; reproduces by seed, roots and vegetative growth Forms up to 2.5 million, pepper-size seeds per plant Seed banks build unnoticed for years, then under the right conditions a widespread infestation may suddenly emerge Seeds float on water and stick to animals Mature stands of purple loosestrife can live up to 20 years Flowers July to September 2.2 million seeds per mature plant originally introduced as ballast in ships along the NE seaboard distributed as a garden ornamental Usually associated with moist or marshy areas Alters wetland ecosystems by replacing native and beneficial plants Dense infestations can impede water flow Displaces nesting habitat for waterfowl, fur-bearing animals and birds Agriculture is impacted by a loss of wild meadows, hay meadows and wetland pastures Distribution Occurs in freshwater and brackish wetlands Found on lakes and waterways throughout King County Sometimes cultivated as a garden ornamental

Purple Loosestrife (Lythrum salicaria)
Class B Noxious Weed Purple Loosestrife (Lythrum salicaria) Rhizomatous perennial; reproduces by seed, roots and vegetative growth Forms up to 2.5 million, pepper-size seeds per plant Seed banks build unnoticed for years then emerge when soils are exposed Seeds float on water and stick to animals Usually associated with moist or marshy areas Alters wetland ecosystems by replacing native and beneficial plants (will out-compete cattails) Dense infestations can impede water flow Causes flush of phosphorus in fall instead of over winter and in spring as with natives Can accelerate eutrophication of downstream water bodies Displaces nesting habitat for waterfowl, fur-bearing animals and birds Aquatic insects are smaller when grown in loosestrife thickets than in native wetland plant communities Distribution Occurs in freshwater and brackish wetlands Found on lakes and waterways throughout King County Sometimes cultivated as a garden ornamental

Garden Loosestrife (Lysimachia vulgaris)
Class B Noxious Weed Garden Loosestrife (Lysimachia vulgaris) Sepals have distinct orange margins Perennial Flowers Yellow, primrose-like Clustered near top of the plant Leaves Lance-shaped Opposite or whorled Dotted with black or orange glands Yellow, primrose-like flowers clustered near top of the plant

Garden Loosestrife (Lysimachia vulgaris)
Class B Noxious Weed Garden 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 whorled Rhizomatous perennial Reaches 5 feet tall Spreads by seeds and short rhizomes. Flowers in July Introduced as a garden ornamental Shares 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.

Policeman’s Helmet (Impatiens glandulifera)
Class B Noxious Weed Policeman’s Helmet (Impatiens glandulifera) Class B Noxious weed Herbaceous annual, ft Leaves Oblong/ovate, opposite Margins are sharply serrate Flower White, pink or purple; June to Sepember Irregular, 5 petals (2 fused) Escapes gardens into ravines, streamsides, parks, woodlands Annual with fleshy, reddish stems, ft tall, flowers resemble English policeman’s helmet, vary in color from white to dark pink-purple

Policeman’s Helmet (Impatiens glandulifera)
Class B Noxious Weed Policeman’s Helmet (Impatiens glandulifera) Emerges: April to May Flowers: Late May to September Seeds: August to October Spreads rapidly by seed if not controlled Native to India, western Himalayas Can grow over 10’ tall Produces seeds per plant Seeds are ejected 15 to 20 feet Competes with native plants for pollinators, reducing the seed set of native plants Considered one of the ‘Top 20” invasives in the United Kingdom Often found invading along creeks Can grow to 10 feet tall in one season

Sulfur Cinquefoil (Potentilla recta)
Class B Noxious Weed Sulfur Cinquefoil (Potentilla recta) Rose family, Perennial, 1-3 ft. tall woody rootstock 5-7 palmate leaflets, Flowers pale yellow Flowers June-July Forms 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, pastures east of Redmond and Covington/Maple Valley area Roots are woody and deep so control methods need to be repeated Digging up roots will work but follow-up is needed because roots will re-sprout Most 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 surfactant Digging: works but need repeat treatments Mowing: does not work, makes root crown grow and stems flower shorter

Dalmatian Toadflax (Linaria dalmatica)
Class B Noxious Weed Dalmatian Toadflax (Linaria dalmatica) Leaves bluish-green with waxy coating, heart-shaped Flowers bright yellow tinged with orange, like snapdragon flowers Bolts: April-June Flowers: May-Sept Seeds: Aug-Sept Scrophulariaceae Perennial herb with erect stems up to 3-4 ft. tall Flowers from May to August Roots are deep and extensive and can break off easily near the surface Leaves alternate, bluish-green with waxy coating, heart-shaped, clasping the stem and are rubbery in texture Flowers are bright yellow, tinged with orange, and resemble snapdragon flowers

Yellow Toadflax (Linaria vulgaris)
Class C Noxious Weed – Control Not Required Yellow Toadflax (Linaria vulgaris) Perennial, 1 to 2.5 feet tall Flowers yellow, smaller than Dalmatian flowers May to September Leaves: Small, narrow, linear, pale green Roads, railroads, industrial areas, trails, ornamental plantings CONTROL Digging small patches Not mowing Dicamba: before bloom stage, repeat as needed Chlorsulfuron (Telar): bud to bloom stage, use penetrating surfactant, will suppress only Glyphosate: actively growing, get complete coverage

Gorse (Ulex europaeus)
Class B Noxious Weed Gorse (Ulex europaeus) Evergreen with large spines Yellow, fragrant pea flowers Flowers in early spring Fire hazard Brought from Ireland to Oregon in the 1800’s Forms extensive stands in coastal and open areas Budding: Feb-March Flowers: March-May Seeds: June-July

Gorse invading a King County forest

Old Man’s Beard (Clematis vitalba)
Class C Noxious Weed – Control Not Required Old Man’s Beard (Clematis vitalba) Climbing, deciduous vine Compound leaves, composed of 5 leaflets (1 to 3 leaflets on seedlings) Creamy white, sweet smelling flowers with four petals Feathery seed heads account for the common name of old man’s beard Older vines have stringy, furrowed bark, which is pale brown in color. Native of Europe and southwest Asia Vigorously climbs over other vegetation and structures, and can be invasive along roadsides, river banks, forest edges and fencelines, and in gardens and disturbed forests Has become a major threat to native forests, covering entire trees and preventing regeneration in forest gaps

Old Man’s Beard or Wild Clematis
Class C Noxious Weed – Control Not Required Old Man’s Beard or Wild Clematis Native of Europe and southwest Asia Vigorously climbs over other vegetation and structures, and can be invasive along roadsides, river banks, forest edges and fencelines, and in gardens and disturbed forests Has become a major threat to native forests, covering entire trees and preventing regeneration in forest gaps Old Man’s Beard on trees in Ravenna Park Old Man’s Beard covering trees at Magnuson Park

King County Noxious Weed Control Program Website
Weed Photo Page: Search by Common Name or Latin Name Click thumbnail picture of plant

Sasha Shaw King County Noxious Weed Program 201 South Jackson St, Suite 600 Seattle, WA

Invasive Weeds on the Middle Fork Snoqualmie

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Invasive Weeds on the Middle Fork Snoqualmie

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