Presentation on theme: "Invasive and Noxious Weeds"— Presentation transcript:
1 Invasive and Noxious Weeds Sasha ShawKing County Noxious Weed Control Program201 South Jackson, Suite 600Seattle, WAkingcounty.gov/weeds
2 Agenda Definitions Impacts How do weeds spread? What can we do to help stop them?What are some of the local invasive weeds?
3 Weedy Definitions Weeds Invasive Weeds Noxious Weeds Plants growing where they are not wantedInvasive WeedsNon-native plants that spread into natural ecosystems and harm those ecosystemsNoxious WeedsWashington State’s legal term for invasive, non-native plants that threaten agricultural crops, human health, local ecosystems or fish and wildlife habitat
4 Why do weeds bother people? Weeds grow where they want to, not where people plant themWeeds take water, food, and space away from the plants we want to growSometimes weeds can be useful in one place but harmful in anotherLike blackberry brambles!Weeds are any plants growing where they are not wanted. Any undesirable grass or broad-leafed plant species, from a small herbaceous plant to a woody shrub, vine, or tree, may be considered a weed if it is growing in a landscape bed, pasture, lawn, rangeland or other area where it is not desired. For example, a corn plant growing in the middle of a lawn would be considered a weed, although easy to control.OUCH!YUM!
5 How are invasive and noxious weeds worse than regular weeds? Not just along roads and backyardsEscape into natural areasPersist and spreadGenerally lack predators and natural controlsNothing eats it and nothing out-competes itHarm the environmentBully plantsThey out-grow, out-spread and out-compete native plantsDisrupt ecosystemsRapidly 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 plants such as English ivy displace native plants and wildlife and can transform entire ecosystems
6 What are some ways noxious weeds harm ecosystems? Decrease biodiversityCrowd out native plantsReduce animal habitat and food sourcesAttract pollinators away from native plantsClog streams and lakesHarm treesIncrease erosionCreate fire hazardsHerb Robert InfestationGarlic Mustard Infestation
7 Where did our Invasive Weeds come from? You are hereMost invasive weeds in Washington come from parts of the world with similar climates, especially Europe and Asia, because they are most suited to our area.
8 How did they get here? Intentional (accidentally on purpose) Ornamental plantingCropsErosion controlAccidentalBallast material in shipsContaminated materialsSeedsHayLive plantsOrnamental escapeeShip ballast and ornamental escapeeSeed and hay contaminantErosion control
9 How do weeds move? Natural Processes Human Causes Wind Water/flooding Birds and other animalsHuman CausesHitchhiking on vehicles, bikes, boots, boats, etcConstruction/GradingMowing/EquipmentYard waste dumpingBeing plantedSeeds can hitch a ride on almost anythingSeeds are tough and can survive being moved around, buried, frozen, carried long distances, even being eaten by animalsSeeds we plant or hay we feed animals sometimes have weed seeds mixed inBoats move fragments of water weeds from lake to lakeBoots and camping equipment move weeds from one place to another; from city to forestIf a plant can grow well here and its seeds are spread by birds, water, wind or animals, then it can invade and spread
10 Invasive Weeds Impact Forests The Environmental Impacts of Noxious Weeds to natural areas are extremely significant.You are possibly familiar with the impact of English choking forested natural areas in the County.Invasive species push endangered species over the brink42% of federally listed endangered species are impacted by invasive speciesInvasive plants are the second most important impact to wildlife after habitat loss and fragmentationThe Oregon Silverspot Butterfly is no longer found in Washington partly because invasive plants like Scotch Broom crowded out the butterfly's native food sources.Invasive plants such as English ivy displace native forest plants, damage trees, and replace the foods wildlife are used to eating
11 Invasive Weeds Impact Lakes Impacts to recreational use of natural areas can also be great, particularly to aquatic natural areas. Here we have fragrant waterlily and Eurasian watermilfoil Choking this aquatic area.Aquatic noxious weeds create swimming hazards, snag boats, and interfere with fishing and boating.Natural areas are the reason many of us live in this regionWe expect our parks to be more than just green:We want natural plant and animal communities; wilderness accessible to urban residentsWe want to be able to boat on the lakes, to fish, to swim.When we go hiking and camping, we want to see natural, diverse ecosystems, not blackberry thickets and ivy desertsAquatic weeds create swimming and boating hazards, lower water quality and damage fish habitat
12 Invasive Weeds Impact Rivers The Nature ConservancyRiver banks become covered by invasive knotweed, keeping out native trees and shrubsKnotweed increases erosion
13 Invasive Weeds Impact Agriculture Cattle checking out a spiny thistleA horse trying not to eat tansy ragwortSignificant control costs for land managersAgricultural costs in terms of reduced livestock and crop productivityUS crop losses are $29 billion a year due to non-native weeds (12% of crop yields)Many important agricultural weeds in Washington State were initially established in the Puget Sound AreaIn King County, significant agricultural impacts are caused by Tansy Ragwort and Milk ThistlePasture weeds crowd out and replace healthy forage* and some weeds can poison animals(*Note: forage means plants that livestock eat)
14 And Invasive Weeds Are Just Downright Obnoxious
16 What does the government do to fight invasive plants and noxious weeds? Prevention and early response for new invadersWatch for new invadersRequire control of certain noxious weeds through state laws and county weed programsProhibit sale of invasive plants and noxious weeds through quarantine lawsReducing the impact of widespread invasive plants and noxious weedsHire crews to remove weeds from high quality forests and replant with native speciesOrganize volunteer events and train community stewardsEducate people about what not to plant and what to remove
17 How can we help stop invasive plants? DODON’TLearn which plants cause problemsWatch for and report new plant invadersControl weeds on your propertyCheck clothing, bike, car and boat for noxious weed “hitchhikers”Volunteer to remove invasive plants at stewardship eventsDon’t plant invasive speciesDon’t dump yard waste or garden clippings in natural areasNever dump your aquarium into a lake or stream
18 Some Local Invasive Weeds (also known as “Neighborhood Bullies”)
19 Himalayan Blackberry (Rubus armeniacus) 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.The canes can take root at the tip when they hit the ground, further expanding the infestation.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.Himalayan blackberry can be evergreen, depending on the site.
20 Himalayan Blackberry Impacts Crowds out other plantsReduces habitat diversityCreates obstacles to wildlife movementShades out tree seedlings
21 Controlling Blackberry First step, cut canes to the groundUse long-handled loppers or prunersPile up cut stemsNext step, dig up root ballsUse sturdy shovels and dig deep to get whole rootSpines are sharp so wear sturdy clothesLong pants/sleevesSturdy shoes or bootsLeather work glovesRemove small patches of blackberry first, then big onesAvoid harming native plants
23 Comparing Native and Invasive Blackberry Native Trailing BlackberryInvasive Himalayan BlackberryLow-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.
24 English Ivy (Hedera helix) Ivy leaves on vines are evergreen, lobed, dull green, with light veins
25 English Ivy ImpactsAdds weight to the tree; creates “sail” effect and makes trees more likely to blow downShades out tree’s leavesIncreases rot on tree barkSmothers understory plants and tree seedlingsCreates cover for rats near homesChris Evans, The University of Georgia,
26 Ivy Control1. Cut vines at about shoulder height and pull them off the trunk below the cut and then keep the area ivy-free.2. Pull ivy up by the roots and roll it up into a ball.Start at the top of the hill and work downUse rakes or potato forks to help yank out roots and gather stemsUse a hand saw or clippers to cut vines and then pull vines off trunkWear gloves and protective clothing since the sap can cause a reaction in some peopleRemove flowers or seed heads you can reachHand pull or dig out accessible plantsClippings need to be removed from the site (can re-root)Mulching- apply an 8” thick mulch layer. The plants can be cut or removed and then mulched, or a mulch layer can be applied directly on top of the plants.Mowing can be effective if done very regularly ( weekly)
27 English Holly (Ilex aquifolium) Tree or bush with spiny, glossy evergreen leaves and red berries.
28 English Holly ImpactsBerries are eaten by birds and deposited in forests, parks and backyardsCan grow so thickly that native trees and plants can’t growHas invaded remote, natural forests where it has spread undetected for many yearsExpensive and difficult to control, especially in remote areas
29 English Holly Control Young seedlings can be pulled up by hand Larger plants have deep roots and have to be dug up with a shovel or large equipmentif you can’t remove all the roots, cut them below groundCutting is only temporaryPlants sprout from root crowns and stemsFollow up by removing new shoots for several years to starve out rootsCan apply herbicide to freshly cut stump or use the hack-and-squirt, girdling or injection methodsEnglish holly control is challenging because you are generally dealing with large trees. Even the small holly plants have extensive, tough roots. The first thing to do is prevent further spread by removing berry-producing trees. Holly trees re-sprout from cut stumps and root crowns so grubbing out the roots is the best non-chemical method. Simply cutting it down will result in years of re-sprouting or multi-stem monsters. Probably the most effective control method is to apply herbicide to a freshly cut stump or use the hack-and-squirt or girdling method (which involves hacking at an angle into the trunk with a small hatchet at regular intervals or completely circling the trunk. The herbicide is then applied into the fresh cuts so it will be translocated down into the roots through the live wood (the cambium). Either glyphosate or triclopyr can be used (see the label for the concentration to use for each). Stem injection of herbicide capsules is another method that shows promise, as well as basal applications for smaller stemmed trees.In this picture, you can see how dense the holly has become in this forest. The area in the foreground had been filled just as densely with holly before it was manually grubbed out the year before. Notice the lack of any shrubs or young trees in the area where the holly was removed. Surrounding parts of this same forest that were less infested with holly had a much more developed tall shrub layer with a mix of young trees in the understory.
30 Note: Native Oregon Grape can look like English Holly Oregon Grape – leaves in pairs, berries blueEnglish Holly – leaves not in pairs, berries redT.J. Neuffer, WSU ExtensionK. MessickT.J. Neuffer, WSU ExtensionWhen looking for young holly volunteers, be careful to distinguish it from the native look-alike, Oregon grape. The leaves look very similar and without the blue Oregon grape berries or yellow flowers, it might be easy to confuse it with young holly plants. One key difference is that holly leaves grow alternately on the stems (there is only one leaf attached at each node). Oregon grape leaves are in groups of leaflets that are arranged in pairs (except for the one at the end).Janet Wall
31 Herb Robert (also called 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 capsules
32 Herb Robert ImpactsSpreads quickly and takes over large areas in forested habitatsInhibits growth of native forest plantsProduces a chemical that keeps other seeds from growingSeeds are sticky and easily spread by people and animalsHitchhikes on hikers into the wilderness where it can spread undetected
33 Herb Robert ControlAnnual 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 capsulesThin, weak roots make this plant easy to pull, but its seeds germinate all season so repeat visits to the same location are needed.
36 Knotweed Impacts Causes expensive problems Damages pavementLimits visibility along roadsImpacts drainage and septic systemsInvades turf and landscapesLowers water quality on rivers by increasing erosion and turbidityForces out native and desirable plantsReduces habitat for fish and other wildlifePrevents tree establishmentOne of the most difficult plants to eradicateConsidered among the worst invasive plants in Europe and North America
37 Knotweed spreads easily Pieces are spread by floods, mowers, beavers, earth moving equipment, and in contaminated fill materialRoot and stem fragments as little as ½ inch can form new plantsStarts 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 plants
38 I think I need a bigger shovel. Knotweed ControlI think I need a bigger shovel.For new or small patches, you can dig up individual plants if they are growing in soft soil. However, big, established plants like this are very hard to dig up, with large, woody rhizomes and deep roots that are very difficult to dig up. Also, since even a small root fragment can re-sprout, expect to see re-growth around where you dig. Careful work will improve success, but you may make the problem worse if too many roots are left behind. Disturbed roots tend to respond with rapid growth of many stems, often extending out away from where you were digging and into new areas. Make sure to dispose of roots and rhizomes in the garbage, since they can survive most composting attempts and they don’t burn well.Digging knotweed up is possible but roots may go down 7 feet deep and extend out 20 feet. Re-sprouting is likely.38
39 Knotweed Control Options Covering with thick, plastic fabric for 5 to 7 years to shade it out. Loose covering allows growth without stems breaking through (you have to stomp it down every few weeks).Injecting herbicide directly into the hollow stems (very effective but you have to inject every stem).Injection: 3ml dose per cane of Glypro (aquatic formulation of Glyphosate). Findings show 5 % regrowth in subsequent years. In 2005, spent 15 days of crew time injecting on the Green River and Soos Creek (hatchery Park).Spraying plants with an herbicide (use one that won’t harm fish if near a river).
40 Giant Hogweed (Heracleum mantegazzianum) Class A Noxious WeedGiant Hogweed (Heracleum mantegazzianum)Perennial ft tallFlowers - many smallwhite flowers in a flattopped umbelStems – thick, ridged, coarse hairs, purple blotchesIntroduced as a garden ornamental; Class A noxious weedEstablishes in shaded riparian areas,including parks and natural areas.15 feet tall with a stout, purple-blotched stem, white umbrella-shaped flower clusters, and giant, jagged leaves
41 Caution: Giant Hogweed Can Cause Burns Juice causes burns when skin is exposed to sunlight, even a day or two after contact with hogweed. Control must be done very carefully. If juice gets on skin, wash immediately.Causes blisters followed by purplish-dark blotches that persist and can continue to be sun-sensitive for several years.
42 Poison Hemlock (Conium maculatum) Poisonous8 to 10 feet tall, stems purple-spottedDig up plants when soil is moistCut flowering stems below crown before seeds matureWear gloves and mow with a face maskParsnip 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
44 Garlic Mustard (Alliaria petiolata) Class A Noxious WeedGarlic Mustard (Alliaria petiolata)
45 Garlic Mustard Class A Noxious Weed In forests, garlic mustard spreads up to 120 feet in one year. It inhibits tree growth through negative impacts on beneficial fungi and has no natural enemies in North America.Now spreading on the Cedar River and Coal Creek area, garlic mustard is on the move in King County
46 Garlic Mustard Control Class A Noxious WeedGarlic Mustard ControlPull it up, bag it up and brush off boots and clothes. Seeds are tiny and spread easily in soil and on boots and clothes.
47 Tansy Ragwort (Senecio jacobaea) Class B Noxious WeedTansy 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.47
48 Tansy Ragwort Infestation in a Pasture Class B Noxious WeedTansy Ragwort Infestation in a PastureA 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.Toxic alkaloids accumulate in animal’s liver causing irreversible damage and eventually death
49 Tansy Ragwort Control Class B Noxious Weed ControlsManual: 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.Roots of rosettes need to be removed completely or they will re-sprout.Pull and bag mature tansy ragwort. Do not leave cut or dried plants on ground (toxic when dry and cut flowers can produce viable seed)
50 Scotch 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 longFrom 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)
52 Scotch Broom can be removed with weed wrenches Keep soil disturbance to a minimum where possibleAt least ten years or more of monitoring site for new seedlingsIf you don’t plan to maintain, don’t bother clearing – will be covered again within 5 yearsPlants under 3 feet can be hand pulled when soil is moistLarger plants can be removed with weed wrenches, claw mattocks, root jacks or other useful tools; do this when the soil is moistClear thick stands or multi-branched plants with manually operated tools: chainsaws, brush cutters, axes, machetes, loppersCut plants near ground level where the stem is more yellow than green in the dry season (July-September)Cut large, mature plants at chest height or below and cut off side branches during the dry seasonKey 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 herbicides; wait 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)
53 Yellow Archangel (Lamiastrum galeobdolon) 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 axilsSilvery markings on leaves of this popular garden plant make it easy to spot invading into shady forests
54 Yellow Archangel taking over the understory of a local forest
55 Yellow Archangel Control – Persistence Required! Hand pulling – loosen soil and carefully remove all the rootsCovering – needs to be very well-covered, no holes and extending out from plantsSpraying – combinations and repeat treatmentNever leave stems lying on the ground or in piles – they will form roots and growIt can take years to get rid of an infestationRegrowth after sprayingSeedlings emerging in treated area
56 For More Information on Noxious Weeds in King County: Weed Photo Page:Search by Weed NameClick thumbnail picture to get more information and photos
57 Sasha Shaw King County Noxious Weed Control Program 206-477-9333 sasha Sasha Shaw King County Noxious Weed Control Program kingcounty.gov/weeds
Your consent to our cookies if you continue to use this website.