Quick viewing(Text Mode)

Water Weeds: Guide to Aquatic Weeds in King County

Water Weeds: Guide to Aquatic Weeds in King County

Weeds: Guide to Aquatic Weeds in King County

Department of Natural Resources and Parks Water and Land Resources Division Noxious Weed Control Program W W A A T T E E R ater eeds: R W W W W E uide to quatic eeds E E G A W E D D S in King County S • •

A A Q Q U U A A T T I I C C

W W E E E E D D S S

I I N N On the cover: parrotfeather Inside cover: purple loosestrife, Department of K floating primrose-willow, Natural Resources and Parks K I Eurasian watermilfoil Water and Land Resources Division I N Page 2: native yellow -lily Noxious Weed Control Program N G (top and bottom) G Page 3: garden loosestrife 201 South Jackson, Suite 600 C Page 4: Brazilian C O Page 5: Seattle, WA 98104-3855 O Page 6: purple loosestrife www.kingcounty.gov/weeds U Page 7: parrotfeather U N Page 8: yellow flag iris 206-296-0290 N T Page 9: common reed T Y Y W W A A T T E E R ContentsAquatic Noxious Weeds Included in This Guide R W W E E E EMERGENT FLOATING MAT E D 1. Common Reed 10 & 11 10. Floating Primrose-willow and Water Primrose 28 & 29 D S S ( australis) (Ludwigia peploides, L. hexapetala) • • 2. Cordgrasses 12 & 13 11. Parrotfeather 30 & 31 A (Spartina alterniflora, S. anglica, S. ( aquaticum) A Q densiflora, S. patens) Q U U A 3. Flowering Rush 14 & 15 FLOATING LEAF A T () T I 12. Fragrant Water Lily 32 & 33 I C 4. Garden Loosestrife 16 & 17 ( odorata) C (Lysimachia vulgaris) W 13. Yellow Floating Heart 34 & 35 W Nymphoides peltata E 5. Grass-leaved Arrowhead 18 & 19 ( ) E E E D (Sagittaria graminea) D S S 6. Hairy Willowherb 20 & 21 SUBMERGED I (Epilobium hirsutum) 14. Brazilian Elodea 36 & 37 I N 7. Purple Loosestrife 22 & 23 () N K () 15. Eurasian Watermilfoil 38 & 39 K I I 8. Reed Canarygrass () N 24 & 25 N G (Phalaris arundinacea) 16. Fanwort 40 & 41 G (Cabomba caroliniana) C 10. Yellow Flag Iris 26 & 27 C O () 17. Hydrilla 42 & 43 O U U To see the complete King County (Hydrilla verticillata) N N T noxious weed list, visit T Y www.kingcounty.gov/weeds Y W W A A T T E by natural controls such as herbivores, and E R What are R aquatic other . Native aquatic plants provide food W and for , birds, and other wildlife. They W E plants? E E protect shorelines from erosion and often clean E D Plants that grow in pollution from the water. D S water are called aquatic S

• plants. They grow in a What are aquatic • variety of forms. Emergent plants noxious weeds? A A are rooted in the and grow along shorelines, Q When aquatic plants are introduced to a new Q U floating plants grow in shallow to deep water and U area without the natural checks and balances A either have floating leaves or form floating mats on A T of their home , they can sometimes grow T I the surface of the water, and submersed plants grow I out of control, creating dense monocultures and C mostly under water. Many native aquatic plants grow C overwhelming lakes and streams. This guide W in Washington, and they are very beneficial to the describes some of these invasive, non-native aquatic W E environment and generally do not cause significant E E plants that have been introduced to Washington’s E problems. These native aquatic plants developed D water bodies (accidentally or as garden D S in the area naturally and usually are kept in check S plants). They are all highly aggressive I and create significant ecological I N N and economic damage when they K are not controlled. These invasive, K I I N non-native aquatic plants are N G called aquatic noxious weeds G

C when they are identified by the C O Washington State Noxious Weed O U U N Board as having a significant N T negative impact on the state’s T Y natural and economic resources. Y   W W A A T T E closely resemble these weeds. If you find a that E R Impacts of R invasive looks like one of the weeds in this guide, we suggest W you consult the more detailed references listed at W E aquatic E E weeds: the back of this guide or ask an expert for help with E D getting a positive identification. D S . loss of native plant S communities • What can we do about • . disruption of fish and wildlife habitat aquatic noxious weeds? A A Q . damage to commercial and sport fishing veryone can help prevent new introductions by Q U E U cleaning boats, trailers and other equipment, by A . reduced recreational activities like boating and swimming A T never dumping into lakes and creeks, T I . clogged irrigation and drinking water structures I C and by not planting invasive aquatic plants. Also, C . decreased water quality. early detection of an invasive aquatic weed greatly W increases the opportunity for preventing damage. If W E E E What aquatic weeds are you find an aquatic noxious weed in a new area, it is E D important that the responsible agency or landowner D S included in this guide? S is alerted as soon as possible, while there is still his guide describes 17 aquatic noxious weeds I T a chance to stop its spread. Even when I N on the Washington State Noxious Weed List to look N invasive weeds are already widely out for in King County. The weeds are grouped K established in a water body, it is still K I by growth form: emergent, floating mat, floating I possible to reduce their impact and N leaves, and submersed. Many of the weeds in N G contain their spread. For instance, it G this guide are already widespread in King County, can help to remove seed heads before C but some of them have only been found in a few C O they mature or to contain the weed by O U locations or only in nearby counties. The guide does U controlling new satellite populations. N not include any native aquatic plants, some of which N T T Y Y   W W A A T T E applies equally to private and E R What should I do R if I find an aquatic public property. However, W this requirement does not W E noxious weed? E E include noxious weeds that E D Mark the location of the plant with a weighted are widespread in the state D S S buoy if it’s in the water, or a flagged stake if it’s on or the county, but only those • the shore, and carefully collect a specimen including weeds where the state weed board • stems, leaves and any flowers or seed pods. Place believes there is still an opportunity to eradicate A A Q the specimen in a sealed container with water and it from all or part of the state. The noxious weeds Q U store in a cool, dark place. Contact the King County are classified by distribution: Class A weeds are the U A Noxious Weed Program at 206-296-0290 to A T highest priority statewide because they are highly T I make arrangements for getting the specimen limited in distribution, Class B weeds have a split I C C identified. If this is not possible, contact the distribution and control is required only where they W weed program and we can help determine if a are not already widespread, and Class C weeds are W E site visit is needed to identify the plant. E E the most widespread and their control is typically not E D required, although recommended where possible. D S What does the State S Noxious Weed Law I How do I know which I N require when it N comes to aquatic weeds have to be K controlled? K I noxious weeds? I N The King County and Washington State noxious N ashington’s noxious weed law (RCW G W weed lists are available online at www.kingcounty. G 17.10) requires property owners to control C gov/weeds or by contacting the King County C and stop the spread of noxious weeds O Noxious Weed Control Program at 206-296-0290. O U on their property, including both aquatic U N In this guide, the weed classification and any control N and non-aquatic noxious weeds. The law T requirement is provided for each weed described. T Y Y   W W A A T T E E R How do I find What help does the R

W out more county provide for W E about permit aquatic noxious weed E E requirements control? E D D S for aquatic S weed control? The King County Noxious Weed Program is • available to provide information and advice on • Since aquatic plants are by definition growing in identification and control methods for aquatic weeds A A Q an easily disturbed, sensitive environment, any work and to guide property owners through the complex Q U done to remove them is regulated by state or local permit regulations that exist when working in U A laws. In order to do any noxious weed removal in aquatic environments. In addition, A T T I water, you need at minimum a pamphlet Hydraulic because of the challenges I C Project Approval (HPA) permit from the Washington involved with controlling C W Department of Fish and Wildlife, which is available aquatic weeds, the noxious W E free of charge from this Web site: http://wdfw. weed program will help E E E D wa.gov/hab/aquaplnt/aquaplnt.htm, or by landowners find out about D S calling 360-902-2534. Other permits from state additional resources and S

I and local agencies may be required for work may be able to provide direct I N involving bottom barriers, mechanical equipment or assistance in some cases for N

K . For assistance, contact the King County the highest priority aquatic K I Noxious Weed Control Program at 206-296-0290 or weeds. Call the program for I N [email protected], the Washington more information at 206-296- N G G State Department of Regulatory Assistance at 800- 0290 or email us at noxious. C 917-0043 or [email protected], and/or your [email protected]. C O O U local city government permitting office. U N N T T Y Y   EMERGENT What we can do about it: Not realistic to control by hand due to six foot deep mass. Prevent 1. Common Reed seed production by cutting off flowerheads or Phragmites removing plants at ground level. should australis only be applied by a licensed aquatic herbicide A A applicator unless the plants are growing away from Q What it is: 12 foot tall Q U the water. Spray actively growing plants with a U A rhizomatous grass with purplish A systemic herbicide. Herbicides are most effective T feathery flower head and stiff blue- T I when flowers are first forming. I C green leaves. Key identification features: no other C grass in this region gets that tall. N What it’s confused with: Pampas grass is also tall N O with feathery plumes, but doesn’t grow in O X Why we care: Forms dense single-species stands at X and forms clumps rather than large clones. Other I water’s edge, can tolerate brackish water. Dense, tall I O ornamental grasses O U growth excludes all other , dramatically U might also fit the S reducing habitat value of shorelines and access to S general description, water. W but aren’t as tall and W E E don’t grow in water. E When we find it: Easiest to recognize when it E D Reed canarygrass D S reaches full height in July, but the previous year’s S is similar but not as dead stalks can indicate presence year round. • tall, more yellow- •

E Where we find it: Freshwater and brackish green in color, and E M lacks the M E wetlands and corridors. Currently one major E R infestation along the Duwamish River in Seattle, with feather plumes. R G smaller infestations in a few other spots, including G E Legal Status: Class E N along the Sammamish River and in Union Bay. N T B, control required T 10 in King County. 11 2. Cordgrasses Where we find it: All of these grasses are currently Spartina alterniflo- in the Puget Sound area. Common cordgrass ra, S. anglica, (Spartina anglica) was found on Vashon Island S. densiflora, beaches several years ago but appears to be S. patens eradicated. Look for cordgrasses on beaches along A A Q Puget Sound, especially on Vashon Island. Q What it is: These four grasses U U A are invaders of saltwater and What we can do about it: Pull seedlings and dig A T . They are generally rhizomatous (except out small clumps, being sure to get all the roots and T I I C S. densiflora) grasses that begin by forming circular . For larger infestations, contact the King C patches at the upper edge of tidelands and then County Noxious Weed Control Program. Herbicide N N O spread out to create dense single-species stands should only be applied by a licensed aquatic O X covering the . Key identification features: herbicide applicator. Apply systemic, non-selective X I I O All of these grasses have ligules (thin membranes aquatic herbicide to actively growing plants. O U that stick up along the stem where the leaf attaches) U S S that look like a fringe of hairs. What it’s confused with: Other beach grasses. The W Spartina species are the only salt-tolerant grasses W E Why we care: Species of spartina can drastically that have a ligule like a fringe of hairs. E E change the nature of Pacific Northwest tidelands, E D D S obliterating mudflats that are critical for oysters Legal Status: Class A, eradication S and other shellfish as well as important habitat for required in King County. • • migratory birds. E E M When we find it: Best to look for it in the M E E R summertime. R G G E E N N T T 12 13 3. Flowering Rush What we can do about it: Carefully dig small Butomus umbellatus infestations, making sure to remove all plant parts (spreads vegetatively). Herbicide should only be What it is: Emergent or applied by a licensed aquatic herbicide applicator. submerged rush-like plant. Spray actively growing plants with a systemic aquatic A Emergent form has stiff A herbicide. If you think you have flowering rush, Q leaves that are triangular in Q U contact the King County Noxious Weed Control U A cross-section; submerged form has A Program for verification. T ribbon-like, limp leaves that float on the water’s T I I C surface. Key identification features: pretty pink What it’s confused with: Several native aquatic C to white flowers in umbrella-like clusters atop plants have ribbon-like underwater leaves, including N N O round stalks. Difficult to identify without flowers. species of bur-reed ( spp.), water- O X Washington has an emergent form that rarely flowers. plantain ( spp.) and arrowhead or duck- X I I O potato (Sagittaria spp.) Sedge O Why we care: Competes with native wetland U species ( spp. or Scirpus spp.) U S and shoreline vegetation and can crowd out more S and giant bur-reed (Sparganium desirable species. W eurycarpum) may have leaves that W E E E When we find it: Blooms from June through August. are triangular in cross-section. E D D S Where we find it: Currently not known in King Legal Status: Class A, eradication S required in King County. • County. Established populations known from • Whatcom and Benton counties. Emergent E E M in saturated soil or shallow water, and M E submerged in water up to nine feet deep. E R R G G E E N N T T 14 15 All photos by Ben Legler 4. Garden Loosestrife Where we find it: Wetlands, stream and river Lysimachia vulgaris corridors, lake margins, ditches, in shallow water or saturated soil. Abundant on Lake Washington, What it is: Tall perennial Lake Sammamish, Lake Burien, the Sammamish, wetland plant with showy Snoqualmie and Raging , and some associated A bunches of five-petalled yellow A wetlands. Not known elsewhere in King County. Q flowers. Key identification features: Q U U A leaves often in whorls of three and usually What we can do about it: Very difficult to control A T have tiny black or orange dots on the underside by hand. At minimum cut the plants at base to T I I C visible with magnification. prevent seed formation. Dig up small infestations, C try to get all the roots. Herbicide should only be N Why we care: Very aggressive plant outcompetes N applied by a licensed aquatic herbicide applicator O even purple loosestrife and hardy natives such O X unless the plants are growing away from the water. X as cattails. Spreads by rhizomes and seeds, plant I Spray actively growing plants with a systemic I O fragments will root. An ecological pest, it crowds out O U herbicide. Discard plants in garbage, not yard waste. U S native plants and has little habitat value for native S animals. What it’s confused with: No native plant looks like W this, but there are many weed species with yellow W E When we find it: Blooms from mid July through E E flowers. E D August. Difficult to spot when not in bloom. D S Legal Status: Class B, control required in King County. S

• •

E E M M E E R R G G E E N N T T 16 17 lants.com, B rip ugw sou o is od M .o , r lia g g . a n e T What we can do about it: Contact the King n 5. Grass-leaved a

D y County Noxious Weed Program for verification b arrowhead

o

t o

h Sagittaria graminea and assistance. P

What it is: Rhizomatous What it’s confused with: Several native species. A emergent plant with narrow A Duck potato () has arrow-shaped Q leaves (occasionally spoon- Q U leaves. Water plantains (Alisma spp.) have spoon- U A shaped) about 20 inches long and A shaped leaves and much smaller flowers. Submerged T sprays of showy three-petalled white flowers about T I forms can be confused with bur-reeds (Sparganium I 2/3 inch across. C spp.) when not in flower. C N N Why we care: Aggressive weed forms monocultures O Legal Status: Class B, control required in O X in shallow water and outcompetes native plants. X I King County. I O Native to eastern North America and readily available O U on the internet, it could be introduced to King U S S County waterbodies. W W E When we find it: Blooms summer into fall. E E E D D S Where we find it: Shallow S • water, muddy shorelines. Can • also grow submerged in deeper E E M water. Currently known from M E Lake Roesiger in Snohomish E R R G County and Mason Lake in G E Mason County. Not known in E N N T King County. T 18 Photo by Jenifer Parsons Photo by Arlene Fullerton 19 6. Hairy Willowherb What we can do about it: Dig out small Epilobium hirsutum infestations, being careful to get all the roots. Mature plants can be cut off at the base to prevent seed What it is: Tall, wetland- production. Mowing does not work and may spread dwelling relative of the native the infestation. Herbicide should only be applied A plant fireweed. Looks similar, A by a licensed aquatic herbicide applicator unless Q with showy magenta flowers and Q U the plants are growing away from the water. Spray U A long skinny seed-pods that burst open to release A actively growing plants with a systemic herbicide. T fluffy white seeds. Key identification features: stem T I Discard plants in garbage, not yard waste. I C and leaves covered with soft hairs; magenta flowers C have four notched petals and a white center; leaves What it’s confused with: Easily confused with the N N native fireweed (Epilobium angustifolium), which O opposite, lance-shaped and toothed along the O X edges; rhizomes thick and spreading. is not hairy. Purple loosestrife (Lythrum salicaria) is X I found in the same , but it has a square stem, I O O U Why we care: Pushes out native wetland plants, smooth-edged leaves and flowers with five petals. U S S can grow densely enough to impede water flow, Legal Status: Priority W spreads easily to undisturbed wetlands. Class C, control W E E E When we find it: Easiest to identify when in flower required in King E D D in July and August. County. S S

• Where we find it: Generally • in places with wet or moist soil; E E M including pastures, meadows, M E wetlands, streambanks and E R lakeshores. Can also spread into R G G E drier areas. E N N T T 20 21 7. Purple Loosestrife fairly common and widespread in King County. Lythrum salicaria What we can do about it: Dig or pull plants in What it is: Tall perennial soft soil, cut plants at base to prevent seed wetland plant with showy, formation. Herbicide should only be applied by a A compact spikes of magenta licensed aquatic herbicide applicator unless the A Q flowers. Key identification plants are growing away from the water. Spray Q U U A features: the stem is actively growing plants with a A T square and the leaves are opposite, systemic herbicide. Always throw T I I C smooth edged and narrow. this plant in the trash, never in C compost or yard waste. N Why we care: Has up to 2.5 N O million seeds per plant, spreads What it’s confused with: O X Hardhack (Spiraea douglasii), X I by rhizomes, and plant fragments I O will root. An ecological pest, it native woody shrub with spikes O U of fuzzy pink flowers and wider, U S outcompetes native plants and S provides little habitat for native alternate leaves; fireweed W (Epilobium angustifolium), tall W E animals. E E upland perennial with more open E D When we find it: Blooms from spikes of pink flowers and alternate D S S mid July through August, but you leaves. Some native plants in the • can find it by the square stems at mint family have square stems, but • other times. the leaves are toothed. E E M Where we find it: Wetlands, M E Legal Status: Class B, control E R stream and river corridors, lake required in King County. R G margins, ditches, wet pastures, in G E E N shallow water or saturated soil. It is N T T 22 23 8. Reed Canarygrass the plant. Herbicide Phalaris arundinacea should only be applied by a licensed aquatic What it is: Rhizomatous sod- herbicide applicator forming wetland grass up to unless the plants are A six feet tall. Key identification A growing away from the Q features: leaves stick out at a Q U water. Spray actively U A wide angle from the stem (like corn), A growing plants with a T leaves have a long ligule (thin membrane that sticks T I systemic, non-selective I up along the stem where the leaf attaches), flower C or grass herbicide. For a C heads are held high above leaves on tall stems. N more thorough discussion N O on reed canarygrass O X Why we care: Highly invasive grass can form solid X I monoculture excluding even the seeds of other control, see our Web site. I O O U plants. Clogs streams and ditches, destroys wetland What it’s confused U S restoration sites, degrades wildlife habitat. with: Many other S grasses, but tends to be W When we find it: Easy to see any time of year – in W E taller, more robust and E E summer when it’s green and vigorous, or in winter E more dense in growth D when the dead flower stalks blanket areas. D S than other grasses that S

• Where we find it: Very common and widespread in grow in wet areas. • King County. Typically found in wet pastures, ditches, E Legal Status: E M wetlands and shorelines. M E Non-regulated noxious E R What we can do about it: The best control is to weed, control not R G shade it out, since it does not do well without full required in King County. G E E N sun. Mowing can reduce its impact but will not harm N T T 24 25 9. Yellow Flag Iris What it’s confused with: Cattail ( latifolia) Iris pseudacorus leaves are not flattened and folded like iris. Nothing else that grows in water looks like it in bloom. What it is: Large yellow iris. This is the only iris in King Legal Status: Non-regulated noxious weed, control A County that grows in water. not required in King County. A Q Bright showy flower, long Q U U A folded leaves. A T T I Why we care: Extensive, tough rhizomes form I C impenetrable mats. Spreads by rhizomes and seeds. C N An ecological pest, it outcompetes native plants and N O degrades habitat of native animals. O X X I When we find it: Blooms late April through June. I O O U Where we find it: Wetlands, stream U S S and river corridors, lake margins, ditches. W Common and widespread in King County. W E E E What we can do about it: Difficult to E D D S control by hand. Often requires repeated S use of heavy tools such as pick-axes or • • hatchets to remove sections of rhizome. E Herbicide should only be applied by a E M M E licensed aquatic herbicide applicator unless E R the plants are growing away from the R G G E water. Spray actively growing plants with a E N systemic herbicide. N T T 26 27 Floating Mat infestation (in a private pond in Renton). There have been other small infestations in the past, successfully A 10. Floating Prim- eradicated. One to look out for! A Q rose-willow and Q U U A Water Primrose What we can do about it: Hand pull or rake up A T Ludwigia peploides, T I small infestations, being sure to get as many roots I C Ludwigia hexapetala as possible (roots will resprout). Herbicide can only C be applied by a licensed aquatic herbicide applicator. N What it is: Low growing perennial that forms mats N O in water up to 10 feet deep. Key identification Apply a systemic herbicide to actively growing plants. O X X I features: showy yellow five-petalled flowers in leaf I O axils, smooth-margined alternate leaves, prostrate What it’s confused with: The native water purslane O U stems float on water. (Ludwigia palustris) has inconspicuous green flowers U S S and opposite leaves. No wetland native has showy W Why we care: Clogs waterways, impedes recreation. yellow flowers like this. W E E E Ecological pest that outcompetes native plants. E D Legal Status: Class A and B, D S S When we find it: Easiest to locate when flowering, control required in • late July to August. King County. •

F F L Where we find it: L O In King County we O A A T currently have one T I small floating primrose- I N N G willow infestation G (on a tributary to the M Green River) and one M A A T small water primrose T 28 29 11. Parrotfeather Where we find it: Currently four known Myriophyllum infestations in small private in King County. A aquaticum Still sold as a plant on the internet A Q Q (illegal to buy or sell it in Washington), so it could U What it is: Spikes of U A potentially be found anywhere. A T feathery leaves emerging up T I to a foot above the water. Key I C What we can do about it: Pull or rake, being very C identification features: no other plant careful to remove all fragments from the water. N has whorls of feathery leaves emerging from the N O Manual control requires persistence over many years. O X water in this manner. Looks like miniature pine trees Herbicide can only be applied by a licensed aquatic X I growing on the water’s surface. I O herbicide applicator. Apply systemic herbicide to O U actively growing plants. U S Why we care: Clogs waterways, wetlands, shallow S ponds, ditches, lake edges, and slow-flowing W What it’s confused with: Underwater stems W E streams and rivers, filling entire from resemble other milfoil species, but above water E E sediment to a foot above E D stems are very distinctive D S water. Eliminates recreation, and hard to confuse with S wildlife habitat, and native • anything else. • plants. Causes economic F damage in agricultural Legal Status: Class B, F L control required in L O areas. Spreads by O A fragmentation. Very difficult King County. A T T I to eradicate. I N N G When we find it: Emerges G

M in late May and persists into M A October. A T T 30 31 Floating What we can do about it: Pull plants A Leaf or use bottom barriers to maintain A Q small areas of open water. Use hand or Q U 12. Fragrant U A mechanical weed cutters or harvesters A T Waterlily to clear larger areas for open water, T I I C making sure to remove cut plants from C What it is: Floating perennial from long, stout water. Persistent pulling of each leaf N as it emerges over several years can N O rhizomes. Round floating leaves (the ubiquitous O X “lily pads”) with the stem attached at a slit in one result in eradication. Herbicide can be X I applied by a licensed aquatic herbicide I O side. Showy flowers are usually white to pink. Key O U identification features: leaves are round and stay applicator. U S floating even as the water level drops (the stems are S W not stiff like our native pondlily). What it’s confused with: The native W E yellow pondlily ( lutea) has E E E ball-shaped yellow flowers and large, D Why we care: Forms dense mats on the water D S surface that impede recreation, creates ideal heart-shaped leaves that are held out S of the water as the water recedes. • mosquito breeding areas, and can alter water quality • by increasing water temperature and decreasing The native watershield (Brasenia F dissolved . Plant die-back in the fall can schreberi) has oval leaves with no slit F L L O contribute to blooms. and the stem attached in the center O A of the leaf, and the lower leaf surface A T T I When we find it: Leaves emerge in spring and and stem are covered in a slippery I N persist until fall. Flowers continuously bloom from gelatinous substance. N G G June through October. L Legal Status: Non-regulated noxious L E Where we find it: Lakes, ponds, slow-moving water weed, control not required in E A A F up to eight feet deep. Widespread and common in King County. F 32 King County. 33 13. Yellow Floating What we can do about it: There is little A Heart information available on the best control methods in A Q Nymphoides Washington, but it can probably be controlled with Q U U A peltata methods used to control fragrant waterlily. Hand A T pulling may work with small infestations, but plant T I What it is: floating, bottom- I fragments will form new plants. Herbicide can only C rooted perennial with several C be applied by a licensed aquatic herbicide applicator. N leaves per stem. The small (3-10 cm) N O floating leaves are nearly round to heart-shaped O X What it’s confused with: The native yellow pondlily X with wavy leaf margins and purplish undersides. I () has ball-shaped yellow flowers and I O One to five flowers per stalk are held above the O U large, heart-shaped leaves that are held out of the U water surface, and they are bright yellow with five S water as the water recedes. The native watershield S distinctly fringed petals. Key identification features: W (Brasenia schreberi) has oval leaves with no slit and W Small floating leaves, showy, yellow, E the stem attached in E E five-petalled flowers. E D the center of the leaf, D S and the lower leaf S Why we care: Forms dense mats on the water surface and stem are • surface that impede recreation, create ideal • covered in a slippery F mosquito breeding areas, and can alter water quality F gelatinous substance. L by increasing water temperature and decreasing L O O dissolved oxygen. Plant die-back in the fall can A Legal Status: Class B, A T contribute to algae blooms. T I control required in I N King County. N G When we find it: Has habits similar to fragrant G

L waterlily. Flowers from June through August. L E E A A F Where we find it: Wetlands, lakes, ponds, slow-moving F water up to 12-feet deep, also can grow in wet mud. 34 35 Submerged What we can do about it: Clean fragments from boats, motors and trailers after boating in 14. Brazilian Elodea infested waters to prevent spread. Hand pull small Egeria densa infestations, taking great care to remove all plant A What it is: Long-stemmed fragments from the water. Dense, whole-lake A Q Q U perennial with visibly smooth infestations can be mowed with a mechanical U A leaves in whorls of four (up to six) harvester to maintain open water (not recommended A T and small white, three-petalled floating for partially infested water bodies). Herbicide can T I I C flowers. Can top out and form mats on the surface. only be applied by a licensed aquatic herbicide C Key identification features: Most leaves in whorls of four. applicator. Contact the King County Noxious Weed N N O Control Program for assistance. O X Why we care: Spreads rapidly by fragmentation, X I I O clogs waterways, impedes recreation, outcompetes What it’s confused with: Hydrilla (Hydrilla O U native species, reduces fish habitat, can alter verticillata) has visibly toothed leaves in whorls of U S water quality. five and grows from tubers. The native American S W waterweed () has smaller leaves in W E When we find it: Summer. whorls of three. E E E D D S Where we find it: Lakes, ponds, slow-moving Legal Status: Class B, control required in selected S water up to 30 feet deep. Known infestations Lakes • areas of King County. • Union, Washington, Sammamish, Fenwick and Dolloff. S S U U B B M M E E R R G G E E D D 36 37 15. Eurasian Water infested waters to prevent spread. Hand pull small milfoil infestations, taking great care to remove all plant Myriophyllum fragments from the water. Dense, whole-lake spicatum infestations can be mowed with a mechanical A harvester to maintain open water (not recommended A Q What it is: Perennial with Q for partially infested water bodies). Herbicide can be U feathery underwater leaves, U A applied by a licensed aquatic herbicide applicator. A T long reddish or green stems and T I small emergent spikes of tiny flowers. Can top out I C What it’s confused with: Native milfoil species, C and form mats on the surface. Key identification which generally have fewer than 14 leaflet pairs N features: leaf “feathers” have more than 14 leaflet N O and hold their shape out of water, and variable- O X pairs, leaves collapse against stem when plant is leaf milfoil, a Class A noxious weed not known in X I removed from water. I O King County. All milfoils O U can be difficult to tell apart. U Why we care: Spreads rapidly by fragmentation, S If you think you have an S clogs waterways, impedes recreation, outcompetes W invasive milfoil, contact W native species, reduces fish habitat, can alter water E the King County Noxious E E quality. E D Weed Control Program for D S verification. S When we find it: Summer. • • Legal Status: Non-regulated Where we find it: Lakes, ponds, slow-moving rivers S noxious weed, control not S U up to 20-feet deep. Fairly common in King County. U B required in B M King County. M E What we can do about it: Clean fragments E R R G from boats, motors and trailers after boating in G E E D D 38 39 16. Fanwort infested waters to prevent spread. Hand pull small Cabomba infestations, taking great care to remove all plant caroliniana fragments from the water. Dense, whole-lake infestations can be mowed with a mechanical What it is: Submerged A harvester to maintain open water (not recommended A Q aquatic weed with opposite, Q for partially infested water bodies). Herbicide can U finely divided fan-shaped U A only be applied by a licensed aquatic herbicide A leaves and showy pink or white T applicator. Contact the King T I flowers held above the surface of the water. Key I C County Noxious Weed Control C identification features: Fan-shaped, branched leaves Program if you find this plant. N on relatively long stalks, arranged opposite one N O O X another on the stem. What it’s confused with: Several X I native aquatic plants. Coontail I O Why we care: Spreads rapidly by fragmentation, O U () has U clogs waterways, impedes recreation, outcompetes S divided leaves that are whorled S native species, reduces fish habitat, can alter W around the stem. marigold W water quality. E (Megalodonta beckii) and water E E E buttercup (Ranunculus aquatilis) D When we find it: Summer. D S both have similar looking S

• Where we find it: Lakes, ponds, ditches, slow- submerged leaves, but they are • moving water up to 30 feet deep. Not currently smaller and alternate on the stem. S S U known from King County. Only known infestation Common bladderwort (Utricularia U B in Washington is in channels off the Columbia River vulgaris) has conspicuous round B M M E around Longview and Kelso. bladders attached to the leaves. E R R G What we can do about it: Clean fragments Legal Status: Class B, control G E E D from boats, motors and trailers after boating in required in King County. D 40 41 17. Hydrilla Washington State is in Pipe and Lucerne lakes in Hydrilla verticillata Maple Valley/Covington.

What it is: Long-stemmed What we can do about it: If you find this plant, perennial with visibly toothed A call the King County Noxious Weed Control Program A Q leaves in whorls of five. Flowers immediately. Q U inconspicuous. Grows from small U A A T tubers. Key identification features: What it’s confused with: Brazilian elodea (Egeria T I toothed leaves in whorls of five, the only aquatic I C densa) has smooth-edged leaves in whorls of four. C plant in Washington growing from tubers. American waterweed (Elodea canadensis) has N smooth-edged leaves in whorls of three. N O Why we care: One of the top 10 federally listed O X X I noxious weeds. Spreads rapidly by fragmentation, Legal Status: Class A, control required in I O clogs waterways, impedes recreation, outcompetes O U King County. U S native species, reduces fish habitat, alters water S quality. Extremely aggressive. W W E E E When we find it: Summer. E D D S S Where we find it: Lakes, ponds, ditches, slow- • moving water up to •

S 30 feet deep. The only S U known infestation in U B B M M E E R R G G E Hydrilla photos by Vic Ramey, E D University of Florida/Center for D Aquatic and Invasive Plants, 42 used with permission. 43 W W A A T T E E R What Services What Can Property R

W Does The Owners Do? W E County Weed Prevent weed infestations: E E Program E D c Follow noxious weed laws and quarantines D S Provide S To County c Never put non-native plants or contents into a • Residents? natural water body • A c Choose non-invasive species for gardens A Q p Early detection and eradication of pioneering infestations Q c Clean boats, trailers, boots, and other equipment before U of high-priority noxious weeds U A entering water or wetlands A T p Weed surveys and consultations T I c Become a Weed Watcher and help find new invaders I C p Best Management Practices and fact sheets for noxious C weeds in the county W Control weed infestations: W E p Cooperative Weed Management Area coordination E E c Obtain necessary permits before working in water E p Advice on the appropriate use of weed control methods D c Use integrated pest management and control weeds D S and tools S safely and appropriately p Training and coordination of Weed Watcher volunteers I c Follow Best Management Practices for aquatic weeds I N to monitor lakes for noxious weeds N p c Properly dispose of noxious weeds and weed seeds K Presentations and K I slide shows on weed c Contact the noxious weed program if you are unsure I N identification and control about what to do N G G c Monitor the area and follow up as needed to keep the C weeds out after the first year of control C O O U U N Contact us with questions and concerns: N T www.kingcounty.gov/weeds or 206-296-0290. T Y Y 44 45 W W A A T T E Wetland and Aquatic Plants E R Resources for R Additional Whose Sales are Prohibited in W Washington State W E Information E “The Quarantine List” E King County Noxious Weed Control Program, E D COMMON NAME SCIENTIFIC NAME D S www.kingcounty.gov/weeds or 206-296-0290 S African elodea Lagarosiphon major • Washington State Department of Ecology, Aquatic Plants, Australian stonecrop • Algae and Lakes, http://www.ecy.wa.gov/programs/wq/ Brazilian elodea Egeria densa A links/plants.html cordgrass, common Spartina anglic A Q cordgrass, dense-flowering Spartina densiflora Q U U A Washington State Department of Fish and Wildlife: Aquatic cordgrass, salt meadow Spartina patens A T Plants and Fish, http://wdfw.wa.gov/hab/aquaplnt/ cordgrass, smooth Spartina alterniflora T I aquaplnt.htm or 360-902-2534 delta arrowhead I C Eurasian watermilfoil Myriophyllum spicatum C W Center for Aquatic and Invasive Plants, University of Florida European frog-bit Hydrocharis morsus-rana W E http://plants.ifas.ufl.edu/ fanwort Cabomba caroliniana E E flowering rush Butomus umbellatus E D An Identification Manual for garden loosestrife Lysimachia vulgaris D S S Washington’s Freshwater Plants, Washington State grass-leaved arrowhead Sagittaria graminea Department of Ecology, June 2001, Publication I hairy willow herb Epilobium hirsutum I N 01-10-032. hydrilla Hydrilla verticillata N marsh dew flower, Murdannia keisak K A Field Guide to the Common Wetland Plants of Asian spiderwort K I Western Washington and Northwestern Oregon, Sarah mud mat Glossostigma diandrum I N N Spear Cooke, Editor, Seattle Audubon Society, 1997. parrotfeather Myriophyllum aquaticum G G reed sweetgrass, tall manna grass Glyceria maxima C Aquatic and Riparian Weeds of the West, slender-leaved naiad, brittle naiad minor C O Joseph M. DiTomaso and Evelyn A. Healy, University of swollen bladderwort O U California Agriculture and Natural Resources, 2003, water caltrap, devil's pod, bat nut Trapa bicornus U N Publication 3421. N T water chestnut, bull nut Trapa natans T Y water primrose Ludwigia hexapetala Y yellow floating heart Nymphoides peltata 46 47 W A T E R IndexCommon & Scientific Names W Brazilian Elodea, 36, 37 Lythrum salicaria, 22, 23 E E Butomus umbellatus, 14, 15 Myriophyllum aquaticum, 30, 31 D S Cabomba caroliniana, 40, 41 Myriophyllum spicatum, 38, 39

• Common Reed, 10,11 Nymphaea odorata, 32, 33 A A Cordgrasses, 12,13 Nymphoides peltata, 34, 35 q Q u U Egeria densa, 36, 37 Parrotfeather, 30, 31 a A t T Epilobium hirsutum, 20, 21 Phalaris arundinacea, 24, 25 i I Eurasian Watermilfoil, 38, 39 , 10, 11 c C Fanwort, 40, 41 Purple Loosestrife, 22, 23 N W o E Floating Primrose-willow, 28, 29 Reed Canarygrass, 24, 25 x E i D Flowering Rush, 14, 15 Sagittaria graminea, 18, 19 o S u Fragrant Water Lily, 32, 33 Spartina alterniflora, 12, 13 s I N Garden Loosestrife, 16, 17 Spartina anglica, 12, 13 W e K Grass-leaved Arrowhead, 18, 19 Spartina densiflora, 12, 13 e I d N Hairy Willowherb, 20, 21 Spartina patens, 12, 13 s G Hydrilla, 42, 43 Water Primrose, 28, 29 • C Hydrilla verticillata, 42, 43 Yellow Flag Iris, 26, 27 O I U Iris pseudacorus, 26, 27 Yellow Floating Heart, 34, 35 n N d T Ludwigia hexapetala, 28, 29 e Y x 48 49 W A T E Production credits R

Content: Sasha Shaw and Katie Messick, W King County Noxious Weed Control Program E E D Design: Megann Devine, King County WLRD S Visual Communications & Web Unit • A Q A U Photographs: most provided by King County staff Q A and the Washington State Noxious Weed Board, U T except where indicated. A I T C I This information is available in alternate formats. C N O Call 206-296-0290 or TTY 711 W X E I E O Printed using soy-based ink on 50% recycled paper, D U 30% post-consumer waste. Please recycle. S S File name: 0904WaterWeedGuide.indd mdev I W N E E K D I S N G • C I O N U D N E T X Y 50 51 Water

in King County

Department of Natural Resources and Parks Water and Land Resources Division Noxious Weed Control Program

201 South Jackson, Suite 600 Seattle, WA 98104-3855 www.kingcounty.gov/weeds 206-296-0290

Top View