A weed is a plant out of place.
Noxious weeds are plants out
of place on a global scale
WSU Forestry and Noxious Weeds
April 28, 2015
Presented by: Sonny Gohrman
Snohomish Count Noxious Weed Coordinator
Weeds …..
Do you wonder where they come from?
What are noxious weeds?
 included on the State Noxious Weed List prepared by
the Washington State Noxious Weed Control Board
 non-native, no native plants are included on the list
 invasive, competitive, highly destructive, and
difficult to control or eliminate
 reduce crop yields and destroy native plant and
animal habitat
 they can damage recreational opportunities, clog
waterways, lower land values, and poison or harm
people and livestock
Who is the Snohomish County
Noxious Weed Control Board?
 Five volunteer voting members appointed by the county
legislative authority.
 Members are appointed from five geographical areas.
One voting member from each geographical area.
 At least four of the voting members shall be engaged in
the primary production of agricultural products.
 There is one nonvoting member on the board who is the
chair of the county extension office or an extension agent
appointed by the chair of the county extension office.
 Each voting board member serves a four year term with a
three term limit.
 The board members do not receive a salary but are
compensated for actual and necessary expenses incurred
in the performance of their official duties.
Who is responsible for noxious weed control?
WE ALL ARE!
 Property owners and managers are responsible for
controlling noxious weeds on their properties
 All property except for Tribal and Federal Government
land are covered under the Washington State weed laws
 When property owners fail to comply with RCW 17.10
the Snohomish County Noxious Weed Control Board
may control noxious weeds or contract for their control
at the expense of the property owner
Owner Responsibility
RCW 17.10.140 Owner's duty to control
spread of noxious weeds.
(1) Except as is provided under subsection (2) of this
section, every owner shall perform or cause to be
performed those acts as may be necessary to:
(a) Eradicate all class A noxious weeds;
(b) Control and prevent the spread of all class
B noxious weeds designated for control in that
region within and from the owner's property; and
(c) Control and prevent the spread of all class B
and class C noxious weeds listed on the county
weed list as locally mandated control priorities
within and from the owner's property.
Forestry
(2) Forest lands classified under RCW 17.10.240(2),
or meeting the definition of forest lands contained
in RCW 17.10.240, are subject to the requirements
of subsection (1) (a) and (b) of this section at all
times. Forest lands are subject to the requirements
of subsection (1) (c) of this section only within a
one thousand foot buffer strip of adjacent land
uses. In addition, forest lands are subject to
subsection (1) (c) of this section for a single fiveyear period following the harvesting of trees for
lumber. [1997 c 353 § 17; 1969 ex.s. c 113 § 14.]
What are the different Classes of
Weeds on the Weed List?
Class A noxious weeds are non-native species
whose distribution in Washington State is still
limited. Eradication is required.
Class B noxious weeds are non-native species
whose distribution is limited to portions of
Washington State. Some are selected by the
County for control.
Class C noxious weeds are already widespread
in Washington. Selected by County Weed Board
for Control
Integrated Vegetation Management
KNOW YOUR ENEMY
Integrated Vegetation Management
approach used as a decision making tool
Step 1 Understand your
ecosystem and the plant that
is your target.
Step 6 Monitor and evaluate
Step 2 Survey and map
infestations
Do the
control work
Basic Components of an
IVM Approach
Step 5 Design a
management strategy
Step 3 Develop threshholds
(economic, aesthetic, legal)
Step 4 Explore control options
(prevention, regulatory, cultural,
mechanical, chemical, biological, no
action)
How do you Control Noxious Weeds?
Control methods incorporated in an IVM approach
 Cultural - management activities that prevent noxious weeds from developing
due to enhancement of desirable vegetation which out-competes or otherwise
resists the weeds, including but not limited to irrigation, seeding, fertilizing,
mulching, pruning and thinning.
 Physical or Mechanical - management activities performed using physical
methods and/or mechanical equipment such as hand removal, barriers,
mowers, brushcutters, flame or hot water weeders, blades, hoes, string
trimmers, or other physical means to control noxious weeds and undesirable
vegetation.
 Biological - management activities performed using insects, animals, birds,
diseases or competing vegetation to control undesirable vegetation.
Appropriate permits should be obtained from WSDA, USDA, EPA or
applicable agency before release of any predator.
 Chemical - management activities performed using herbicides registered by
the EPA and the Washington State Department of Agriculture.
 Regulations – laws aimed at preventing or controlling noxious weeds. Both
the quarantine law and the weed law are examples of weed control by
regulation.
Pacific Northwest Weed
Management Handbook
This section of the Handbook contains chemical and nonchemical methods for weed and brush control in forestry.
Herbicide rates, timing, application methods, and cautions are
all found here. This is a WSU publication and all sections of
the Handbook can be downloaded or purchased in hard copy.
Forestry Section
http://pnwhandbooks.org/weed/otherareas/forestry-and-hybrid-poplars/forestry
Resources
Websites:
Bing and Google (ask them anything)
• Washington State Noxious Weed Control Board
http:/www.nwcb.wa.gov/
• Snohomish County Noxious Weed Control Board
http://snohomishcountywa.gov/722/Noxious-Weeds
More Resources
Websites:
• Washington State Noxious Weed Control Board
http:/www.nwcb.wa.gov/
• Snohomish County Noxious Weed Control Board
http://snohomishcountywa.gov/722/Noxious-Weeds
Books:
• Weeds of the West (WEEDS)
• Plants of the Pacific Northwest Coast (NATIVES)
• Weed Control in Natural Areas of the Western
United States (CONTROL OPTIONS)
What Weeds Should
You Look For?
Any
noxious weeds
on the list!!
tansy ragwort
(Senecio jacobaea)
tansy ragwort
(Senecio jacobaea)
The Plant
• Tansy ragwort came to Washington in
contaminated hay and straw in the 1940's.
• Seeds may remain viable for up to 15 years
with up to 150,000 seeds per plant.
• As a biennial, tansy ragwort spends the first
year in the rosette stage. During the second
year, one or several flowering stems bolt, with
the overall plant being one to four feet high.
• Flower heads are in flat-topped clusters. Each
flower head is composed of yellow, daisy-like
flowers. Each flower head is a composite of
many disc flowers surrounded by (usually) 13
ray flowers or “petals”.
common tansy
(Tanacetum vulgare)
This is
NOT
tansy
ragwort
tansy ragwort
Toxicity
(Senecio jacobaea)
Horses and cattle may die from consuming 3 to 7 percent of their body
weight. Young animals are 2 to 3 times more susceptible to poisoning than
mature animals.
Chronic, cumulative poisoning, and irreversible liver damage,
including cirrhosis of the liver are the results of ragwort poisoning.
These toxic properties remain in cut plants found in hay. The alkaloids
also leach into the hay and toxicity is not affected by drying.
Plants wilting after herbicide application or left in the field after
pulling will become more palatable to the animals. Because a sugar
conversion takes place, the tansy becomes less bitter and animals will eat
full size plants. The plants are no less toxic.
All plant parts are toxic, with the highest amount of alkaloids in the
flowers, followed by the leaves, roots, and stems.
Control of Tansy Ragwort
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Several selective broad leaf herbicides that will not harm surrounding
grasses are available. Roundup is also effective, but is not selective and will
kill any vegetation that it contacts. Always use a surfactant to increase
herbicide uptake and reduce herbicide use.
The following insects are used to control tansy ragwort: Cinnabar moth,
Ragwort seed fly, Tansy ragwort flea beetle.
Mowing will extend the life of the plant and cause vegetative spread.
Clipping and pulling is effective.
Pulled plants need to be removed from fields with livestock, livestock needs
to be removed from fields that have been sprayed.
Unless plants can be burned immediately after pulling, burning is not
recommended
giant hogweed
(Heracleum mantegazzianum)
Plants reach a height of 10 to 15 feet.
Stems are stout, hollow, 2 to 4 inches
in diameter, and are covered with
coarse, white hairs and purple blotches.
The stems are covered with coarse,
white hairs and purple blotches.
Large, incised compound leaves can
expand to 5 feet across.
Numerous, small white flowers
cluster to make an umbrella-shaped
inflorescence which is 2 to 3 feet in
diameter.
In Snohomish County, giant hogweed
is often confused with the native cow
parsnip. Although quite similar, cow
parsnip is a significantly smaller plant,
blooming at a height of 4 to 6 feet.
Threat CLASS A
giant hogweed
 A native of the Caucasus Mountains of Asia, giant (Heracleum mantegazzianum)
hogweed has been introduced as an unusual garden
ornamental.
When skin contact occurs in the presence of sunexposure, a glucoside contained in the sap of the
plant can cause severe skin irritations, burns, and
large watery blisters. The scars left behind can be
permanent.
 Plants are now escaping home gardens and
becoming problematic in riparian areas, excluding
native vegetation and causing erosion problems. It is Stems
found along roadsides, gardens, vacant lots,
barnyards, orchards, streams, and rivers.
Control:
Repeated mowing during the season weakens plants,
but the tuberous roots can remain alive for many
years. Pulling is effective, but all roots must be
removed. Roundup herbicide is an effective
chemical control. Contact the Weed Control Board
for site-specific control recommendations.
Burns
Canada thistle
(Cirsium arvense)
Control
Mechanical Methods:
• Repeated tillage at 21-day intervals for
about four months can be effective on
minor infestations of Canada thistle.
• Repeated mowing to weaken stems and
prevent seeding is also effective. Mowing
needs to be repeated three or more times
during the growing season.
• The best long-term approach to
controlling thistle is increasing
competition. Shallow plowing increases
the likelihood that seeds will be eaten by
birds or other animals, or will be broken
down by soil microbes.
Biocontrol Potentials:
• Ceutorhynchus litura, eat young thistle
shoots, but do little damage.
• Urophora cardui, a seedhead gall fly is
the most promising biological control
agent..
• Rhinocylluss conicus and Larinus planus
are both seedhead weevils.
Canada thistle
(Cirsium arvense)
• Herbicides:
• Effective control can be
achieved by using several
broad-leaf herbicides that do
not harm grasses.
• Control is most effective
when herbicides are applied
in the early bud stage and
when the plant is actively
growing.
• For more site specific control
recommendations, please
refer to the latest edition of
the Pacific Northwest Weed
Control Handbook or call
your local Noxious Weed
Control Board.
• Always Read and
Understand the Label
bull thistle
(Cirsium vulgare)
bull thistle
(Cirsium vulgare)
The Plant
• The plant comes from Europe and is
present throughout the United States
and Canada.
• Biennial, 1.5 to 5 feet tall, branched
from base with prickly stems.
• Purple flower heads are 1.5 to 2.5
inches in diameter.
Control
• Control by cultivation is very effective.
Cut the taproot 2 – 3 inches below the
crown and pull the plant>
• Many broadleaf selective herbicides are
effective. Roundup can be used for nonpasture or spot treatments.
• Seed production can be effectively
controlled by mowing before buds are
fully formed.
poison hemlock
(Conium maculatum)
poison hemlock
(Conium maculatum)
•Biennial grows to 10 feet tall. Give away
identification separating it from other
members of the Parsley Family is the
purple mottling on the stem. Introduced
as a garden ornamental from Europe it
has escaped to roadsides, gravel pits,
waterways, croplands, pastures, etc. All
parts of the plant are poisonous. Used to
kill Socrates. In cattle, symptoms can
appear in as few as 12 minutes. Early
spring leaves are especially toxic.
Mowing controls seedset. 2, 4-D or
trichlopyr provides effective herbicide
control.
spotted knapweed
(Centaurea biebersteinii)
• Biennial or short lived perennial. Introduced from Europe. Pink or purple
flower. Long taproot prevents pulling as a viable control. Very aggressive
infesting large areas quickly invading range and open areas. Mowing may
arrest seed development if the plant is mowed early. Various herbicides are
the most effective control method for knapweed, 2,4-D, Transline .
diffuse knapweed
(Centaurea diffusa)
orange hawkweed
(Hieracium aurantiacum)
yellow hawkweed
(Hieracium caespistosum)
Threat/Impacts
Hawkweeds are highly invasive, with
the ability to produce by seed,
stolons, rhizomes and root buds.
Once established some species can
produce 3200 plants per square yard.
Unpalatable to grazing animals.
Hawkweed spreading from roadsides
replaces forage species in rangelands,
pastures and meadows
DESCRIPTION
 Policeman’s helmet is an annual.
Grows up to 10 feet tall.
 The stems are hollow and the
leaves are oblong to egg-shaped,
with serrated edges.
 The flowers range in color from
white to pink to purple and the
shape resembles an old-fashioned
English policeman’s helmet.
When touched, the mature
seedpod splits and ejects its seeds
up to 20 feet.
MANAGEMENT OPTIONS
Policeman’s Helmet can be
controlled with herbicides or by
mechanical means. Plants can be
easily pulled and this is quite
effective for all but very large
infestations. Contact the Weed
Control Board for site-specific
control recommendations.
policeman’s helmet
(Impatiens glandulifera)
THREAT
A native of Asia,
policeman’s helmet, also
called poor man’s orchid.
It was probably
introduced into the United
States as a garden
ornamental.
As this plant often grows
along streams and ditches,
seeds can be quickly spread
downstream by water. A
single plant can produce up
to 800 seeds, which are
viable for 18 months or
more. The seeds can even
germinate under water.
policeman’s helmet
(Impatiens glandulifera)
purple loosestrife
(Lythrum salicaria)
Plant
•A perennial plant.
•Purple-magenta colored flowers grow on
long spikes. Can grow up to 10 feet tall
and 5 feet wide.
•Thirty to fifty stems arise from a common
rootstock. One plant produces up to 2 1/2
million seeds, which spread easily by
wind, water or other means. Four to six
sided main stem.
•Easily confused with fireweed and spirea.
Threat
• Introduced from Eurasia as an
ornamental and in ship ballast
dumped on the East Coast.
• Has spread across the US. It was
first reported in Washington in
the 1920’s and is present in 25 of
the 39 Washington counties.
• The Winchester Wasteway near
Vantage, WA is a 50,000 acre
area, 23,000 acres affected, 5000
acres are solid coverage.
• Nothing lives in it or benefits
from it. No food value except to
bees and its too dense for cover.
purple loosestrife
(Lythrum salicaria)
Control
Bio Control options include a bio the
Galerucella pusilla and calmariensis beetles
which defoliate the plant. These were
introduced in Washington in 1992 and have
been used in Snohomish County since 1999.
Digging The intertwined woody root
system makes it difficult to pull established
plants. Plants under a year old are easier to
remove. Root sections will resprout if the
entire root is not removed.
Mowing Cut stem pieces from mowed
plants will also send out roots unless the
stems are allowed to dry out rapidly.
 Herbicide Some chemical controls are
effective.
garlic mustard
Alliaria petiolata
•During the rosette stage, garlic mustard
resembles several native plants found in
the shaded forest understory: Viola ssp.,
and several plants in the Saxifrage
family, including Tellima grandiflora
(fringecup) and Tolmiea menziesii
(piggy-back plant).
The white taproot
is slender, and forms an "s" shaped curve
just below the crown.
Scotch broom
Cytisus scoparius
• Woody perennial
• Produces up to
18,000 seeds per
year. Seed bank
is up to 60 years.
• Very adapted to
our climate.
• Prefers poor soil.
gorse
Ulex europaeus
Gorse is a perennial, evergreen
shrub ranging from 3 feet to
over 10 feet tall with stout and
erect spreading branches with
angular stems and a terminal
thorn.
Plants grow outward, leaving a
center of dry, dead vegetation.
Individual plants can be up to 30
feet in diameter forming dense,
impenetrable thickets. The
combination of dead plant matter
and a high oil content create a fire
hazard.
Spurge laurel
is a shrub that
typically
reaches a
maximum
height of six
feet.
Spurge laurel
Daphne laureola
It poses a threat to native ecosystems,
including Douglas fir forests and is
particularly problematic in San Juan County.
A close-up of spurge laurel's
glossy leaves and unripe,
green fruits. Once used as an
ornamental shrub, it is rarely
seen in nurseries today. This
shrub has toxic compounds in
the berries, bark, and sap, so
use extreme caution when
cutting this plant and keep
berries away from children
and pets.
Italian arum
Italian arum
Italian arum (Arum italicum)
A perennial, herbaceous plant that can grow
as a dense colony. Leaves and flowers grow
from tubers, with leaves emerging in the
autumn that are oval or arrowhead shaped.
Leaves will remain all winter and die back in
the summer or in colder climates they die
back in the winter, reemerge in the spring, and
then die back in the summer. Flowers bloom
in the spring and summer and form orange-red
berries.
Himalayan Blackberry
Evergreen Blackberry
•Rubus discolor
Rubus laciniatus
Other noxious
weeds we love to
hate, or at least
we should!!
Butterfly Bush
English Holly
English Ivy
Reed Canarygrass
KNOTWEED
The
Knotweeds
•Japanese knotweed
Polygonum cuspidatum
•giant knotweed
• Native to Japan & Asia.
Hybrid first identified in
Polygonum sachalinense
Czechoslovakia.
•Himalayan knotweed
• A Class B noxious weed.
Polygonum polystachyum • Hollow stems resemble
bamboo.
•Bohemian knotweed
• Dense stands up to 12
Polygonum Bohemicum
feet tall. 10,000-60,000
stems per acre.
• Thrives in any moist
soils.
• Spreads by roots & stem
fragments.
• The hybrid (Bohemian)
may spread by seeds.
Seeds are viable.
Effect of noxious weeds on
the riparian zone
• A fully functional riparian zone should
contain diverse native species of
various ages within multiple canopy
layers, and a well-developed shrub
layer. Invasive species out compete
native species for available resources,
and displace the native understory,
altering and simplifying the natural
ecosystem.
Knotweed Understory
Knotweed can form a
monoculture understory
in riparian hardwood
stands. The knotweed
seriously impacts the
recruitment of juvenile
trees and may alter
the successional
development of
riparian forests.
North bank of the Hazel Hole area, Stillaguamish River, 2005
Juvenile Tree Abundance
Hazel Hole Before and After
North Fork Stillaguamish River
•10/8/2007
•9/24/2002
Washington Wilderness
Hay And Mulch
Establishes Minimum Standards
•Field inspection
•Inspection
certificate
•Forage tag
•Twine
Washington Wilderness
Hay And Mulch
• Fields in this program are inspected for noxious
weeds and are certified by WSDA as noxious
weed free. The list of weeds that are inspected
for is broader than the State Weed List.
• Contact
http://agr.wa.gov/PlantsInsects/WWHAM/WWHAM.aspx
Tom Wessels
Plant Services Program Manager
360-902-1984
[email protected]
Open Board Positions
on the
Snohomish Count Noxious
Weed Control Board
A chance to go after the
County’s worst weeds…….
Weed Board Districts
•VACANT
•VACANT
Snohomish County Noxious Weed Control
Board Contact
Geraldine Saw
Snohomish County Noxious Weed Coordinator
8915 Cathcart Way
Snohomish, WA 98296
(425) 388-7548 office
(425) 238-0367 cell
[email protected]
http://snohomishcountywa.gov/722/Noxious-Weeds
QUESTIONS?