Backyard Invasions: Noxious Weeds in Seattle's Greenspaces

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Backyard Invasions Noxious Weeds in Seattle's
Greenspaces

• Sasha Shaw
• King County Noxious Weed Program
• 206-296-0290
• sasha.shaw_at_metrokc.gov

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Agenda

• Definitions
• Impacts of Invasives in Urban Areas
• Invasive Vines, Trees, Shrubs and Other Plants
• What Can We Do?
• Resources

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What is a Weed?

• a plant out of place
• takes water, nutrients or habitat from desired
  plants (subjective)
• threatens an areas values or benefits

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Are All Weeds Bad All the Time?

• Lots of weedy plants are used by birds, insects
  and people
• One persons weed can be another persons pride
  and joy
• Native plants used to be called weeds
• and still are for some!

American goldfinch lunches on bull thistle seeds
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What are Native Plants?

• Adapted to local climate and soils foundation
  for local ecosystem
• Co-evolved with native animals
• Provide food, shelter, nesting materials for
  wildlife

Gumweed (Grindelia integrifolia) on Puget Sound
beach, native to Pacific coast from BC to
California
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What is an Invasive Weed?

• Non-native, aggressively spreading
• Destructive
• Competitive
• Difficult to control

Invasive knotweed spreading into an open forest
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Good Plant
Bad Weed
Bleeding Heart (Dicentra formosa)
Herb Robert (Geranium robertianum)

• Some invasive weeds resemble native plants
• Invasive weeds exploit conditions similar to
  their home range and dont have natural enemies
  keeping them in check

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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)
• control required only where weed is not
  widespread
• goal of law is to prevent spread of new invaders
  to un-infested areas

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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!

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How do weeds get here?
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Noxious Weeds Run Amok
Orange Hawkweed from garden store to mountain
meadow
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Impacts of Invasive Weeds
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Environmental Impacts
Invasives like English Ivy transform forests and
natural areas, hurting trees, native plants and
native wildlife species
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Diverse wetland habitat in the Nisqually delta
provides food and shelter for many different
kinds of birds and animals.
Purple and garden loosestrife in Portage Bay
choke out native plants and destroy wildlife
habitat.
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Impacts to Waterways
Restoration crew removes reed canary grass that
had filled in a stream channel, increasing
flooding and reducing fish habitat
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Impacts to Recreation
Fragrant water lily and Eurasian watermilfoil in
Lake Sammamish
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Impacts to Public Health
Giant Hogweed - Sap sensitizes skin to UV
radiation, resulting in severe burns, blisters,
painful dermatitis and scarring.
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Impacts of Invasives in Seattle
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Seattle Urban Nature Project

• City-wide Surveys 1999-2000 and 2005
• 8,000 acres of public lands in Seattle
• Classified habitat types throughout the city
• Recorded species names and percent cover
• Study of all forest types in Seattle
• Mapped density of invasives

Ella Elman Nelson Salisbury, Ecologists (206)
522-0334 www.seattleurbannature.org
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Invasive Plant Species Citywide
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Most Prevalent Invasive Species
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Invasive TreesAn Overlooked Threat

• Seattle has 2500 acres of forested parkland
• 60-70 of tree regeneration in Seattles forests
  is non-native
• Shade tolerant species are the biggest threat
  English holly and cherry laurel are the worst
• European species of mountain-ash, hawthorne, and
  cherry are found throughout Seattles forests
• If nothing is done, 30 to 40 years from now our
  forests will look dramatically different than
  they do today

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Tree Regeneration
Conifer/deciduous Forests
Conifer/madrone Forests
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Case Study Deadhorse Canyon Inventory

• Distribution of English holly and cherry laurel
• Red and orange high density
• Yellow moderate
• Green low

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Invasive Trees Evergreen
English holly
Portugal laurel
Cherry laurel
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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

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English Holly(Ilex aquifolium)

• can form thickets of large, densely packed trees
  in shady forests or open areas
• spreads by seeds eaten by birds can establish in
  remote areas
• re-sprouts indefinitely from cut stumps so
  digging is best non-chemical method

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Holly Look AlikeTall Oregon Grape
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English Laurel or Cherry Laurel (Prunus
laurocerasus)

• Evergreen tree or shrub to 20 feet high
• Leaves leathery, glossy, 3 to 7 inches, slightly
  toothed
• Flowers white, fragrant, in elongated clusters
• Native to Eastern Europe, Asia Minor
• Common landscaping hedge

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English Laurel (Prunus laurocerasus)

• Fast-growing
• 25 inches or more per year
• Fruit fleshy, black with a large pit (stone)
• Widely escaped in local natural areas and
  woodlands
• Highly toxic if ingested
• poisonous parts wilted leaves, twigs (stems),
  seeds

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Invasive Trees Deciduous
European Mountain-ash
English Hawthorne
Sweet Cherry
Norway Maple
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English Hawthorne (Crataegus monogyna)
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European Mountain-ash (Sorbus aucuparia)
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European Sweet Cherry (Prunus avium)

• A small to medium sized tree, generally to 50
  feet, with a broadly rounded crown
• Leaf 2 to 5 inches long with serrated margin
• Flowers showy, white, one inch across
• Cherries sweet, dark red to nearly black, 1/2 to
  1 inch across

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Norway Maple (Acer platanoides)

• Common shade tree
• Escaping into Seattle forests
• Similar to native bigleaf maple, but the leaf is
  not as large or deeply cut
• Seeds spread their wings wider and have no
  bristly hairs

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Invasive vines

• Form dense groundcovers excluding all native
  plants
• Climb up and smother trees
• Add weight to tree canopies

English ivy
Old mans beard
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English or Atlantic Ivy(Hedera hibernica, H.
helix)
Class C Noxious Weed Control Not Required
Ivy leaves are evergreen, lobed, dull green,
with light veins
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English or Atlantic Ivy(Hedera hibernica, H.
helix)
Class C Noxious Weed Control Not Required

• 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

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English Ivy
Class C Noxious Weed Control Not Required
Ivy mats smother understory plants and tree
seedlings - changing the natural succession
patterns of forests.
Ivy climbs trees, weighs down branches, shades
leaves, damages bark
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Old Mans Beard(Clematis vitalba)
Class C Noxious Weed Control Not Required
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Old Mans Beard or Wild Clematis
Class C Noxious Weed Control Not Required
Old Mans Beard on trees in Ravenna Park
Old Mans Beard covering trees at Magnuson Park
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Invasive Shrubs
Scotch broom
Himalayan blackberry

• Form dense thickets excluding all native plants
• Establish in disturbed sites
• Spread by birds, wind and people

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Himalayan Blackberry(Rubus armeniacus or Rubus
discolor)
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Evergreen Blackberry(Rubus laciniatus)
http//www.biopix.dk
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Himalayan Blackberry(Rubus discolor)
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Good Guy Look AlikeNative Trailing
Blackberry(Rubus ursinus)
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Scotch Broom (Cytisus scoparius)
Class C Noxious Weed Control Not Required
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Scotch broom removal with weed wrenches
Class C Noxious Weed Control Not Required
Controlling Scotch broom with weed wrenches at
Marymoor Park
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Cotoneaster Shrubs

• Thornless shrub up to 15" tall with arching
  branches
• Small leaves white-hairy underneath
• Little white flowers and dull red fruits
• Colorful fruits attractive to birds leading to
  easy spread and invasiveness
• Increasingly common in Seattles forests

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Invasive Perennials and Groundcovers

• Fast-growing invasives push out native
  wildflowers and groundcover species
• Tall perennials out-compete even shrubs and small
  trees especially on streams
• Often escapees from gardens or spreading from
  yard waste dumps

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Giant Hogweed (Heracleum mantegazzianum)
Class A Noxious Weed
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Giant Hogweed (Heracleum mantegazzianum)
Class A Noxious Weed
Cutting the large, fleshy stems may spray sap on
exposed skin
Hogweed scars remain sensitive to sunlight for
several years
Hogweed burns are often painful and slow to
recover
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Giant Hogweed (Heracleum mantegazzianum)
Class A Noxious Weed
Hogweed leaves are large and deeply dissected,
stems are hairy with purple blotches
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Garlic Mustard (Alliaria petiolata)
Class A Noxious Weed
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Garlic Mustard (Alliaria petiolata)
Class A Noxious Weed
Dense infestation along Longfellow Creek
Growing on a stump in the forests of Golden
Gardens Park
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Class A Noxious Weed
Garlic Mustard (Alliaria petiolata)
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Policemans Helmet (Impatiens glandulifera)
Class B Noxious Weed
Annual with fleshy, reddish stems, 3-10 ft tall,
flowers resemble English policemans helmet, vary
in color from white to dark pink-purple
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Policemans Helmet (Impatiens glandulifera)
Class B Noxious Weed
Policemans helmet spreads along creeks and
out-competes and crowds out other plants
Can grow to 10 feet tall in one season
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Policemans Helmet (Impatiens glandulifera)
Class B Noxious Weed
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Class B Noxious Weed
Policemans Helmet (Impatiens glandulifera)
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Knotweeds (Polygonum spp.)
Class B Noxious Weed Control Not Required
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Class B Noxious Weed Control Not Required
Typical stand of Bohemian knotweed with stiffly
upright male flower clusters
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Knotweed Invasion on Rivers
Class B Noxious Weed Control Not Required
Knotweed rapidly spreads along rivers as
fragments get moved by floods and grow into new
clones downriver
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Despite knotweeds large rhizome mass, it
provides poor erosion control
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Herb Robert (a.k.a. Stinky Bob)
Class C Noxious Weed Control Not Required
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Herb Robert (a.k.a. Stinky Bob)(Geranium
robertianum)
Class C Noxious Weed Control Not Required
Shallow roots make this plant easy to pull but
seeds germinate all season so repeat visits to
the same location are needed.
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Yellow ArchangelLamiastrum galeobdolon (a.k.a.
Lamium)
Proposed Class C Noxious Weed Control Not
Required
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
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Yellow Archangel (Lamiastrum galeobdolon)
Proposed Class C Noxious Weed Control Not
Required
Yellow archangel spread aggressively into this
Kirkland-area forest
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Poison Hemlock (Conium maculatum)
Class C Noxious Weed Control Not Required
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Poison Hemlock (Conium maculatum)
Class C Noxious Weed Control Not Required
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Aquatic Weeds

• Choke out native water plants
• Reduce fish and wildlife habitat value of streams
  and lakes
• Endanger swimmers and boaters
• Highly costly to manage once established and
  almost impossible to eradicate

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Eurasian Watermilfoil (Myriophyllum spicatum)
Class C Noxious Weed Control Not Required
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Eurasian Watermilfoil (Myriophyllum spicatum)
Class C Noxious Weed Control Not Required
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Fragrant Waterlily (Nymphaea odorata)
Class C Noxious Weed Control Not Required
Infestation on Cottage Lake
Showy flower and notched leaves
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Purple Loosestrife (Lythrum salicaria)
Class B Noxious Weed
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Purple Loosestrife (Lythrum salicaria)
Class B Noxious Weed
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Garden Loosestrife(Lysimachia vulgaris)
Class B Noxious Weed
Sepals have distinct orange margins
Yellow, primrose-like flowers clustered near top
of the plant
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Garden Loosestrife(Lysimachia vulgaris)
Class B Noxious Weed
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Common Reed (Phragmites australis)
Class C Noxious Weed County-select

• Large perennial grass
• Freshwater or brackish water
• Can grow to 12 feet tall
• Leaf sheath loose
• Reproduction mostly by rhizomes

Tall feathery flower head
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Common Reed (Phragmites australis)
Class C Noxious Weed County-select
Creeping rhizomes and stolons help this plant
spread along waterways and form large clones
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Eek! What Can We Do?
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First, Start at Home

• Learn to recognize eliminate noxious weeds
  before they establish
• Choose non-invasive species for landscapes
  gardens
• Control seed production at a minimum
• Replant with appropriate species
• Dispose of noxious weeds properly
• Check vehicles, clothing and equipment

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Control Methods for Noxious Weeds Management
Manual
Mechanical
Chemical
Biological
Control Chart by Minnesota Sea-Grant
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Manual Control

• Pull seedlings and young plants when small,
  before root systems fully develop
• Remove as much of the root as possible
• Limit disturbance and be sure to follow-up

Digging purple loosestrife
Manual control of Scotch broom
Pulling and bagging tansy ragwort
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Mechanical Control

• Useful to reduce size, seed production and to
  starve roots, especially when plants cover large
  areas
• Weeds will resprout after mowing and can be
  spread on equipment if not careful
• Best results when combined with manual control

Himalayan Blackberry can be mowed to remove
brambles
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Chemical Control

• Safety
• Use with caution, protect skin and eyes
• Always follow the directions on the label
• Prevent drift into water, other plants, etc
• Applications
• Spot treatments, target the weed and avoid injury
  to desirable plants
• Incorporate other treatment methods
• Choose the least harmful herbicide that is
  appropriate for the weed and the site

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Sheet Mulching

• Mulching
• Suppresses weeds improves soil
• Techniques
• Bark, compost, newspaper, cardboard
• Geotextile fabric
• Plastic

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Finally, Disposal and Follow up

• Disposal
• Remove flowers seeds bag and send to landfill
  or burn
• Composting use for common invasives, not for
  noxious weeds
• On-site composting vs. clean green yard waste
• Monitor
• The second and third year are crucial for
  effective weed control

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Next Step,Become a Weed Warrior

• Watch for new plant invaders
• Volunteer at invasive removal work parties and
  stewardship events
• Organize your friends, co-workers, and neighbors
  to adopt a park or natural area
• Spread the word on neighborhood bullies!

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Local Contacts for Volunteering

• King County Parks and Open Space
• Volunteer Coordinator Tina Miller, 206-296-2990
• Calendar http//dnr.metrokc.gov/wlr/pi/calendar.h
  tm
• Watershed Stewardship Directory
• groups and agencies helping to preserve and
  restore King County's watersheds
• http//dnr.metrokc.gov/wlr/wsdir/index.cfm
• Seattle Urban Forests
• Contact Peter Noonan, [phone]
• Seattle Parks
• http//www.seattle.gov/parks/volunteers/index.htm
  
• Seattle Creeks
• Contact Bob Spencer, [phone]

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Seattle Urban Nature Newsletter

• Sign up for newsletter at
• www.seattleurbannature.org
• It is a free, quarterly publication sent out by
  e-mail only. Each issue features information
  about SUN research in Seattles forests and our
  current community projects.

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King County Noxious Weed Program

• 6 year-round staff and 8 seasonal weed
  specialists
• Goal is to prevent and reduce the economic,
  environmental and social impacts of noxious weeds
  
• Weed surveys, education and outreach, landowner
  contact, site specific control options

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King County Noxious Weed Program Staff

• Program Manager Steve Burke
• Education Coordinator Sasha Shaw
• Admin Specialist Suzanne Rowe
• State Lands Coordinator Sean MacDougall
• County Lands Coordinator Roy Brunskill
• Aquatic Weed Specialist Katie Messick
• Seasonal Weed Specialists
• Amy Yahnke, Dennis Chambreau, Trish MacLaren,
  Sarah Baker, Monica Walker, Karen Peterson, Maria
  Winkler, Frances Lucero
• Contact us at 206-296-0290 or noxious.weeds_at_metrok
  c.gov

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King County Noxious Weed Control Program Website
http//dnr.metrokc.gov/weeds
Weed Photo Page Search by Common Name or Latin
Name
Click thumbnail picture of plant
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Sasha Shaw King County Noxious Weed Program201
South Jackson St, Suite 600Seattle, WA
98104206-263-6468sasha.shaw_at_metrokc.govwww.dnr.
metrokc.gov/weeds