Download Seattle Invasive Weed Slide Show

Backyard Invasions: Noxious
Weeds in Seattle's Greenspaces
Sasha Shaw
King County Noxious Weed Program
206-296-0290
[email protected]
Agenda
 Definitions
 Impacts
of Invasives in Urban Areas
 Invasive Vines, Trees, Shrubs and Other
Plants
 What Can We Do?
 Resources
What is a Weed?
a
plant out of place
 takes
water, nutrients or
habitat from desired
plants (subjective)
 threatens
an area’s
values or benefits
Are All Weeds Bad All the Time?

Lots of weedy plants
are used by birds,
insects and people
 One person’s weed
can be another
person’s pride and joy
 Native plants used to
be called weeds

American goldfinch lunches on
bull thistle seeds
and still are for some!
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
What is an Invasive Weed?
 Non-native,
aggressively
spreading



Destructive
Competitive
Difficult to
control
Invasive knotweed spreading into an open
forest
Good Plant
Bleeding Heart (Dicentra formosa)


Bad Weed
Herb Robert (Geranium robertianum)
Some invasive weeds resemble native plants
Invasive weeds exploit conditions similar to their home
range and don’t have natural enemies keeping them in
check
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
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!
How do weeds get here?
Noxious Weeds
Run Amok:
Orange Hawkweed:
from garden store to
mountain meadow
Impacts of Invasive Weeds
Environmental
Impacts
Invasives like English Ivy transform forests and natural areas,
hurting trees, native plants and native wildlife species
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.
Impacts to Waterways
Restoration crew removes reed canary grass that had filled in a
stream channel, increasing flooding and reducing fish habitat
Impacts to Recreation
Fragrant water lily and Eurasian watermilfoil in Lake Sammamish
Impacts to Public Health
Giant Hogweed - Sap sensitizes skin to UV radiation, resulting in
severe burns, blisters, painful dermatitis and scarring.
Impacts of Invasives in Seattle
Dan DeLong/Seattle Post-Intelligencer
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
Invasive Plant Species Citywide
Percent cover of invasive species present in Seattle's
urban forests
Trace (0-10%)
Very High (>100%)
11%
20%
High (81-100%)
Low (11-30%)
9%
25%
18%
17%
Moderately High
(51-80%)
Medium (31-50%)
In 47% of Seattle’s forests, the majority of
the plant cover consists of invasive species
Most Prevalent Invasive Species
Five most invasive species in Seattle based on 1999-2000 survey
1200
1000
Acres
800
600
400
200
0
Himlalayan
blackberry
(Rubus
discolor)
English ivy
Scotch broom
(Hedera helix)
(Cytisus
scoparius)
Species
English holly
(Ilex
aquifolium)
Old man's
beard
(Clematis
vitalba)
Invasive Trees:
An Overlooked Threat
 Seattle has 2500 acres of forested parkland
 60-70% of tree regeneration in Seattle’s 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 Seattle’s forests
 If nothing is done, 30 to 40 years from now our
forests will look dramatically different than they
do today
Tree Regeneration
Native
Conifer
5%
Native
Deciduous
24%
Madrone
3%
Non-Native
Deciduous
40%
Non-Native
Evergreen
28%
Conifer/madrone Forests
Native
Conifer
12%
Native
Deciduous
25%
Non-Native
Deciduous
8%
Non-Native
Evergreen
55%
Conifer/deciduous Forests
Case Study:
Deadhorse
Canyon Inventory

Distribution of
English holly and
cherry laurel
 Red and orange
high density
 Yellow moderate
 Green low
Invasive Trees: Evergreen
English holly
Portugal laurel
Cherry laurel
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
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 nonchemical method
Holly Look Alike:
Tall Oregon Grape
www.PlantSystematics.org
http://bellquel.bo.cnr.it/scuole/serpieri/erbario
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
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
Invasive Trees: Deciduous
European
Mountain-ash
English
Hawthorne
Sweet Cherry
Norway Maple
English Hawthorne (Crataegus monogyna)
European Mountain-ash (Sorbus aucuparia)
European Sweet Cherry (Prunus avium)



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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
Norway Maple (Acer platanoides)



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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
www.hort.cornell.edu
Invasive vines
 Form
dense groundcovers excluding
all native plants
 Climb up and smother trees
 Add weight to tree canopies
English ivy
Old man’s beard
Class C Noxious Weed – Control Not Required
English or Atlantic Ivy
(Hedera hibernica, H. helix)
Ivy leaves are evergreen, lobed, dull green, with light veins
Class C
Noxious Weed
– Control Not
Required
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
Class C Noxious Weed – Control Not Required
English Ivy
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
Class C Noxious Weed – Control Not Required
Old Man’s Beard
(Clematis vitalba)
Class C Noxious Weed – Control Not Required
Old Man’s Beard or Wild Clematis
Old Man’s Beard on trees in Ravenna Park
Old Man’s Beard covering trees at
Magnuson Park
Invasive Shrubs
Scotch broom
 Form
Himalayan blackberry
dense thickets excluding all
native plants
 Establish in disturbed sites
 Spread by birds, wind and people
Himalayan Blackberry
(Rubus armeniacus or Rubus discolor)
Evergreen Blackberry
(Rubus laciniatus)
http://www.nic.funet.fi
http://www.biopix.dk
Himalayan Blackberry
(Rubus discolor)
Good Guy Look Alike:
Native Trailing Blackberry
(Rubus ursinus)
Class C Noxious Weed – Control Not Required
Scotch Broom (Cytisus scoparius)
Class C Noxious Weed – Control
Scotch
broom
removal
Not Required
with weed wrenches
Controlling Scotch broom with weed wrenches at Marymoor Park
Cotoneaster Shrubs




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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
Seattle’s forests
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
Class A
Noxious Weed
Giant Hogweed
(Heracleum mantegazzianum)
Class A
Noxious Weed
Giant Hogweed
(Heracleum mantegazzianum)
Hogweed burns are often
painful and slow to recover
Cutting the large,
fleshy stems may
spray sap on
exposed skin
Hogweed scars remain
sensitive to sunlight for
several years
Class A Noxious Weed
Giant Hogweed
(Heracleum
mantegazzianum)
Hogweed leaves are large and
deeply dissected, stems are
hairy with purple blotches
Class A Noxious Weed
Garlic Mustard (Alliaria petiolata)
Class A Noxious Weed
Garlic Mustard (Alliaria petiolata)
Dense infestation along
Longfellow Creek
Growing on a stump in the
forests of Golden Gardens Park
Class A Noxious Weed
Garlic Mustard (Alliaria petiolata)
Class B Noxious Weed
Policeman’s Helmet (Impatiens glandulifera)
Annual with fleshy, reddish stems, 3-10 ft tall, flowers resemble English
policeman’s helmet, vary in color from white to dark pink-purple
Class B Noxious Weed
Policeman’s Helmet (Impatiens glandulifera)
Policeman’s helmet spreads along creeks
and out-competes and crowds out other
plants
Can grow to 10 feet tall in one season
Policeman’s Helmet (Impatiens glandulifera)
Class B
Noxious
Weed
Policeman’s Helmet (Impatiens glandulifera)
Class B
Noxious
Weed
Class B Noxious Weed – Control Not Required
Knotweeds (Polygonum spp.)
Class B Noxious Weed – Control Not Required
Typical stand of Bohemian knotweed with stiffly upright male flower clusters
Class B Noxious Weed – Control Not Required
Knotweed Invasion on Rivers
Knotweed rapidly spreads along rivers as
fragments get moved by floods and grow into new
clones downriver
Despite knotweed’s large rhizome mass, it provides poor erosion control
Class C Noxious Weed – Control Not Required
Herb Robert (a.k.a. Stinky Bob)
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.
Proposed Class C Noxious Weed – Control Not Required
Yellow Archangel
Lamiastrum galeobdolon (a.k.a. Lamium)
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
Proposed Class C Noxious Weed – Control Not Required
Yellow Archangel (Lamiastrum galeobdolon)
Yellow archangel spread aggressively into this Kirkland-area forest
Class C Noxious Weed – Control Not Required
Poison Hemlock (Conium maculatum)
Class C Noxious Weed – Control Not Required
Poison Hemlock (Conium maculatum)
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
Eurasian Watermilfoil
(Myriophyllum spicatum)
Class C
Noxious
Weed –
Control Not
Required
Eurasian Watermilfoil
(Myriophyllum spicatum)
Class C
Noxious
Weed –
Control Not
Required
Class C Noxious Weed – Control Not Required
Fragrant Waterlily (Nymphaea odorata)
Showy flower and notched leaves
Infestation on Cottage Lake
Class B Noxious Weed
Purple Loosestrife (Lythrum salicaria)
Class B Noxious Weed
Purple Loosestrife (Lythrum salicaria)
Garden Loosestrife
(Lysimachia vulgaris)
Class B
Noxious Weed
Sepals have distinct
orange margins
Yellow, primrose-like flowers
clustered near top of the plant
Class B Noxious Weed
Garden Loosestrife
(Lysimachia vulgaris)
Class C Noxious Weed – County-select
Common Reed (Phragmites australis)
•Large perennial grass
•Freshwater or brackish water
•Can grow to 12 feet tall
•Leaf sheath loose
•Reproduction mostly by rhizomes
Tall feathery flower
head
Class C Noxious Weed – County-select
Common Reed (Phragmites australis)
Creeping rhizomes and stolons help
this plant spread along waterways and
form large clones
Eek! What Can We Do?
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
Control Methods for Noxious
Weeds Management
Manual
Mechanical
Chemical
Biological
Control Chart by Minnesota Sea-Grant
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
Pulling and bagging tansy ragwort
Manual control of Scotch broom
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
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
Sheet Mulching
Mulching

Suppresses weeds & improves soil
Techniques
Bark, compost, newspaper, cardboard
Geotextile fabric
Plastic

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
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!
Local Contacts for Volunteering

King County Parks and Open Space



Watershed Stewardship Directory



Contact: Peter Noonan, (206)233-5019
Seattle Parks


groups and agencies helping to preserve and restore
King County's watersheds
http://dnr.metrokc.gov/wlr/wsdir/index.cfm
Seattle Urban Forests


Volunteer Coordinator: Tina Miller, 206-296-2990
Calendar: http://dnr.metrokc.gov/wlr/pi/calendar.htm
http://www.seattle.gov/parks/volunteers/index.htm
Seattle Creeks

Contact: Bob Spencer, (206) 684-4163
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
Seattle’s forests and our current
community projects.
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
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
[email protected]
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
Sasha Shaw
King County Noxious Weed Program
201 South Jackson St, Suite 600
Seattle, WA 98104
206-263-6468
[email protected]
www.dnr.metrokc.gov/weeds