Rank
|
Latin name
|
Common name
|
Notes
|
HIGH AND MEDIUM
IMPACT SPECIES
|
MH
|
Acer platanoides
|
Norway
Maple
|
Escaping
in the Portland area. Documented in Eugene at Skinner Butte Park (in large
populations), Alton Baker Park and Hendricks Park.
|
M
|
Aesculus hippocastanum
|
Horsechestnut
|
Present
in several places in south portion of Hendricks Park, known to be a problem
in other cities.
|
M
|
Ailanthus altissima
|
Tree-Of-Heaven
|
Very
invasive, especially in more disturbed sites. Coming into prairie on west
side of Skinner Butte, spreading rapidly around Beltline/I-5 area.
|
SH
|
Alliaria petiolata
|
Garlic
Mustard
|
One
of the most invasive forest understory plants in the East and Midwest; now
established in the Portland area and up the Columbia Gorge. A Working Group
has formed to address this species in the Willamette Valley.
|
H
|
Brachypodium sylvaticum
|
False
Brome
|
Highly
invasive grass expanding very rapidly in forests and along rivers in our area
in numerous places. It may drastically change forest understories. In the
northwest Corvallis area it also invades upland and wetland prairies (threatening
rare, native species). A Working Group has formed to address this species in
western Oregon.
|
H
|
Buddleja davidii
|
Butterfly
Bush
|
Invading
riparian zones and other areas in western Oregon and Washington. Can
outcompete native willows which are essential host plants for native butterflies.
Called B. variabilis in some sources. Deadheading is infeasible
because of the long flowering and fruiting time.
|
H
|
Clematis vitalba
|
Traveler’s-Joy
|
Vigorous
climber in Portland and Seattle, also in our area. Somewhat difficult to
distinguish between this and the native clematis (C. ligusticifolia).
|
M
|
Cotoneaster spp.
|
Cotoneasters
|
Escaping
in native prairies, savannas and woodland edges. (Cotoneaster lacteus,
C. franchetti, C. horizontalis, C. parneyi, etc. Best to be very cautious
with any red-fruited ornamentals that appeal to birds.)
|
H
|
Crataegus monogyna
|
English
Hawthorn
|
Dominates
wetland and upland prairies, savannas, and understories in woodland and
forest areas. A very serious problem in the Portland area, Corvallis, Umpqua
Valley, and on the increase here.
|
H
|
Cytisus scoparius
|
Scot’s
Broom
|
Serious
problem in prairies and savannas, along the Willamette, at the coast, etc.
Watch also for a closely-related invasive species, Cytisus striatus
(Portuguese Broom).
|
H
|
Daphne laureola
|
Spurge
Laurel
|
An
increasing problem in woodlands around Eugene, Corvallis, McMinnville
(dominating a 52 ac. hillside there, according to CWMA coordinator), Portland,
Seattle, Vancouver B.C.
|
M
|
Digitalis purpurea
|
Foxglove
|
Widely
escaped, especially in foothills of Cascades and Coast Range. Forms large
stands, particularly in clearcuts and along roadsides. Also in mesic meadows.
Likely introduced originally for medicinal purposes, but now also planted for
aesthetic reasons.
|
H
|
Egeria densa
|
Brazilian
Waterweed
|
Established
and dominant in Coyote Creek north of Fern Ridge Reservoir, Lake Creek below
Triangle Lake, and several other Willamette Valley and nearby coastal sites.
A very aggressive aquatic invader.
|
H
|
Fallopia ×bohemica
F. japonica
F. sachalinensis
|
Bohemian
Knotweed
Japanese
Knotweed
Giant
Knotweed
|
All
formerly classified in the genus Polygonum. Form monocultures in
riparian or other moist habitats. Bohemian most frequent in Lane County.
Occurs along McKenzie, Willamette, and Tenmile Creek, and at Sweet Creek
Falls trailhead. See the related Persicaria wallachii (Himalayan
knotweed), also. A Working Group has formed to address these species in the
Willamette Valley.
|
MH
|
Foeniculum vulgare
|
Fennel
|
S.
side Skinner Butte and north side Willamette just upstream from Valley River
Center shopping center (both Eugene), Hwy. 58 roadside at Lookout Point
Reservoir, I-5 shoulders (Eugene), etc. Occasional in other places locally,
but expanding rapidly. Extensive in coastal southern Oregon and northern
California.
|
M
|
Genista monspessulana
|
French
Broom
|
Spreading
rapidly by seed in Coburg Hills, invading meadows with rare species. Serious
problem in CA and OR south coast; now appearing in Eugene.
|
H
|
Geranium lucidum
|
Shining
Crane’s-Bill
|
In
the last 10 years has become a dominant in forest and oak woodland understories
in the central and southern Willamette Valley. Especially thrives in
riparian areas, and other shady sites.
|
H
|
Geranium robertianum
|
Herb
Robert (Stinky Bob)
|
Dominates
forest understories all over the greater Portland area and Columbia Gorge, and
is now becoming regular at the Coast, in Eugene and Corvallis. Up the
McKenzie River at least as far as lower delta of Horse Creek.
|
H
|
Hedera helix
H. hibernica
|
English
Ivy
Irish
Ivy
|
Completely
overruns forest understories and riparian areas. An immense and expensive
problem. H. hibernica may be more common as an escapee in the Eugene
area than H. helix. Additional species may be present in limited
areas.
|
H
|
Heracleum mantegazzianum
|
Giant
Hogweed
|
ODA
has worked hard to control two populations of this in Lane County. It likely
will show up again.
|
M
|
Hypericum perforatum
|
St.
John’s Wort
|
Planted
for medicinal use, but has spread widely into meadows and roadsides in the
Valley and Cascades.
|
MH
|
Ilex aquifolium
|
English
Holly
|
Appears
regularly in forest understories. Spread by birds.
|
M
|
Impatiens glandulifera
|
Policeman’s
Helmet
|
Four
locations in Wolf Creek Drainage. Also in Alsea drainage, and near Portland.
|
H
|
Iris pseudacorus
|
Yellow
Flag Iris
|
Forms
monocultures in wetlands. Has established itself in Bertelsen Slough, Amazon
Creek, other west Eugene wetland areas, and now is regular along the
Willamette River. Also, Kelly Creek in upper Siuslaw watershed, Leaburg Lake
(reservoir) on the McKenzie River, Portland and Columbia River habitats
|
M
|
Juniperus virginiana
|
Eastern
Redcedar
|
Birds
eat berries and spread seeds. Occurs in Willow Creek Preserve (TNC) and
other wetlands in west Eugene.
|
H
|
Leucanthemum vulgare
|
Oxeye
Daisy
|
Widely
escaped in upland prairies, along roadsides. Formerly Chrysanthemum
leucanthemum. Watch also for Chrysanthemum maximum (Shasta daisy)
which occasionally appears as an escapee.
|
M
|
Lamiastrum galeobdolon
|
Yellow
Archangel
|
Primarily
moved by humans. Very aggressive, primarily moving out from landscaped
areas. Escaped in Eugene, Springfield, Corvallis, and Seattle (where it
“covers hillsides,” according to a botanist there).
|
M
|
Lathyrus latifolius
|
Sweet,
Perennial Or Everlasting Pea
|
Well
established, primarily along roadsides and hedgerows. Now moving higher into
the Cascades.
|
M
|
Ligustrum vulgare
|
Common
Privet
|
Naturalizing
on slopes of Skinner Butte in partial shade to shade. Occasional elsewhere
in the greater Eugene area.
|
M
|
Linaria genistifolia ssp. dalmatica
L. vulgaris
|
Dalmatian
Toadflax
Butter
And Eggs
|
Both
move in along roadsides, then invade native meadows in the Cascades. A few
clumps are present along BPA corridor in S. Eugene, and in Kirk Park at Fern
Ridge.
|
H
|
Lotus corniculatus
L. uliginosus
|
Birdsfoot
Trefoil
Greater
Birdsfoot Trefoil
|
L.
corniculatus (and
possibly L. uliginosus) sold in pasture and rough lawn mixes. Invade
and dominate wet and moist prairies.
|
M-H
|
Ludwigia hexapetala
L. peploides
|
Water
Primrose; Floating Primrose Willow; others
|
Pests
in both flowing and ponded water. One or both are known from Smith and Bybee
Lakes and along the lower Columbia Slough, the Corvallis area, and in the
Eugene area in Delta Ponds, Spring Creek, Golden Gardens Ponds and along the
lower Amazon.
|
M
|
Lunaria annua
|
Honesty;
Money Plant
|
Somewhat
invasive in forest understories; widespread.
|
M
|
Lychnis coronaria
|
Rose
Campion
|
Becoming
established in lower Horse Creek watershed of upper McKenzie River (east Lane
County) and along Middle Fork Willamette, where it can dominate open areas
and stream banks
|
H
|
Lythrum salicaria
|
Purple
Loosestrife
|
Forms
near-monocultures in wetlands. Has been found in along Amazon Creek and the
Willamette River. Immense problem across the continent.
|
M
|
Lysimachia nummularia
|
Moneywort
|
Regular
dominant of riparian wetlands in our area, both in sun and shade.
|
H
|
Mentha pulegium
|
Pennyroyal
|
Widespread
in emergent wetlands in west Eugene Wetlands and elsewhere. Difficult to
control.
|
M
|
Melissa officinalis
|
Lemon
Balm
|
Widespread
weed in native prairies and openings in woods.
|
H
|
Myriophyllum spp.
|
Parrot’s
Feather, etc.
|
Includes
water-milfoils. Myriophyllum aquaticum (M. brasiliense;
parrot’s feather) is the most common, and M. spicatum (Eurasian
milfoil) also is impacting aquatic habitat.
|
M
|
Nasturtium officinale
|
Watercress
|
Chokes
out small waterways on the valley floor. Up the McKenzie as far as lower
Horse Creek. ( = N. aquaticum; Rorippa nasturtium-aquaticum)
|
H
|
Nymphoides peltata
|
Yellow
Floating Heart
|
Known
from two private ponds: one in SE Springfield, one in Marcola. Recent
addition to ODA list.
|
H
|
Pentaglottis sempervirens
|
Evergreen
Bugloss
|
Large
escaped population on Lorane Highway along Spencer Creek; small populations
in NW Lane County, Cottage Grove, Masonic Cemetery (Eugene); likely it is
frequently misidentified as Anchusa. Widespread escapee in NW Oregon
counties.
|
H
|
Persicaria wallachii
|
Himalayan
Knotweed
|
Documented
as an escapee below Blue River Dam, and more common on the N. Coast. One of
the “giant” knotweeds (see Fallopia also; was Polygonum polystachum).
|
H
|
Phalaris aquatica
|
Harding
Grass
|
P.
aquatica
infests drier areas than reed canarygrass, and is newer to the area. It is expanding
very rapidly in west Eugene near and other areas in the Willamette Valley.
Seed for sale on the internet 1/2008.
|
H
|
Phalaris arundinacea
|
Reed
Canarygrass
|
Phalaris
arundinacea
is a widespread problem in wetlands and riparian areas, forming huge
monocultures. Control is very difficult, primarily because of water-side
locations. A variegated form of this grass is forming large monocultures
along the Metolius River (Jefferson Co.) and along Tenmile Creek estuary
(Lane Co.) at the Coast. That form also has been seen in the Bull Run
Watershed east of Portland, but it is not yet documented in our area. Seed
for sale on the internet, 1/2008.
|
---
|
Polygonum spp.
|
Giant
Knotweeds
|
See
Fallopia.
|
SH
|
Potentilla recta
|
Sulphur
Cinquefoil
|
Extremely
invasive in far eastern OR and eastward. Just beginning to show up here; was
being sold accidentally in a native plant outlet in our area, so likely is
established here. Not easy to separate from the native Potentilla
gracilis.
|
H
|
Prunus avium
|
Sweet
Cherry
|
Shades
out forest understories. A widespread problem.
|
MH
|
Prunus laurocerasus
P. lusitanica
|
English
Laurel
Portugal
Laurel
|
Appear
regularly in forest understories, sometimes common.
|
M
|
Prunus cerasifera
P. domestica
P. spinosa
|
Thundercloud
Plum
Domestic
Cherry
Sloe
|
Grafted
species and rootstocks that sucker and flower, produce fruit spread easily by
birds & raccoons. Not as invasive as P. avium.
|
SH
|
Pueraria montana var. lobata
|
Kudzu
|
This
vine has a reputation in the South of being the worst (or nearly so) invasive
plant to ever escape there. It is valued for medicinal properties. It
recently has shown up twice in the Willamette Valley. Formerly known as P.
lobata.
|
M
|
Pyracantha spp.
|
Firethorn
|
Birds
eat fruits and spread plants into prairies. P. angustifolia, P. coccinea,
et al.
|
MH
|
Pyrus communis
P. calleryana
|
Domestic
Pear
Callery
Pear
|
Both
become thorny as they revert to non-horticultural forms. Callery includes
the widely used “Bradford” and “Autumn Blaze” cultivars, as well as others.
Sterile when alone, but fertile when different introductions cross-pollinate.
|
H
|
Ranunculus ficaria
|
Lesser
Celandine
|
Highly
invasive in Hendricks Park, Mt. Pisgah Arboretum, and more recently, upper
Amazon Creek and Tugman Creek (and many other areas in the Willamette Valley).
Very difficult to control. A look-alike, Caltha palustris (yellow
marshmarigold), does not seem to be invasive in the southern Willamette
Valley area.
|
H
|
Ranunculus repens
|
Creeping
Buttercup
|
Highly
invasive and widespread, especially on moist riparian terraces. It forms
large monocultures, especially in moist areas.
|
MH
|
Robinia pseudoacacia
|
Black
Locust
|
Widely
escaped east of the Cascades, beginning to naturalize on West Side: Portland
area; Benton County; Lane County, Highway 126 east and west of Eugene, lower
Horse Creek Delta (McKenzie Bridge). Has been seen in significant numbers in
west Cascades timber sale areas. Can form woodland monocultures.
|
M
|
Rosa eglanteria
|
Sweetbriar
Rose
|
Invades
native prairies: mostly upland, occasionally wetland.
|
MH
|
Rosa multiflora
|
Multiflowered
Rose
|
Nationwide
problem escapee. Oregon Department of Transportation has planted it widely.
A major problem in West Eugene Wetlands, Fern Ridge Wildlife Area and E.E.
Wilson Wildlife Area in Benton County.
|
H
|
Rubus armeniacus
R. vestitus
|
Armenian
Blackberry
European
Blackberry
|
Very
invasive and widespread. Expensive control measures are being widely
implemented. Identification of R. vestitus likely is lumped under R.
armeniacus. (Note: Himalaya Blackberry, R. discolor, has not been
documented here.)
|
M
|
Rubus laciniatus
|
Evergreen
Blackberry
|
Not
as invasive as R. armeniacus, but forms dense clumps.
|
M
|
Saponaria officinalis
|
Bouncing
Bet
|
Forming
dense patches along Willamette River at Elijah Bristow State Park.
|
M
|
Securigera varia
|
Crown
Vetch
|
Known
at sites near Hills Cr. Reservoir and Blue River Reservoir; also escaped
around Corvallis. Formerly known as Coronilla varia.
|
M
|
Solanum dulcamara
|
Bittersweet
Nightshade
|
Widespread
in many wetlands and riparian area.
|
H
|
Ulex europaeus
|
Gorse
|
Still
occasionally planted. Very serious infestations on central and south coast,
now appearing in numerous sites in Willamette and Umpqua valleys.
|
M
|
Verbascum blattaria
|
Mullein
|
Colonized
sandy/gravelly river bars and banks. Especially problematic east of the
Cascades, but increasing in our area.
|
MH
|
Viburnum opulus var. opulus
|
European
Cranberry Bush; Snowball Bush
|
Extensive
population around Patterson Slough. Rare/occasional elsewhere along the
Willamette River in Eugene.
|
M
|
Vinca major
V. minor
|
Greater
Periwinkle
Lesser
Periwinkle
|
Mostly
near old home sites—they appear to primarily spread vegetatively. Capable of
completely dominating understories.
|
SUSPECTED / WATCH
LIST
|
S
|
Acer pseudoplatanus
|
Sycamore
Maple
|
Aggressively
invading shady areas and wetlands in Portland area.
|
S
|
Acanthus mollis
|
Bear
Breeches
|
Spread
by dumped yard debris, very difficult to get rid of, long-lived. Seen outside
of Brownsville on Timber Road, on Wallace Creek road outside of Springfield,
and other areas.
|
S
|
Aegopodium podagraria
|
Goutweed
|
Escaping
from landscaped areas into wild areas: Eugene, Oakridge, Fall Creek.
|
S
|
Aesculus glabra
|
Ohio
Buckeye
|
Naturalizing
and thriving in one area along Oak Creek, just NW of Corvallis.
|
S
|
Ajuga reptans
|
Ajuga;
Common Bugle
|
Reported
as escaping, but data are needed.
|
S
|
Alchemilla mollis
|
Lady’s
Mantle
|
Scattered
reports; may be associated with garden waste dumping.
|
S
|
Amorpha fruiticosa
|
False
Indigo
|
“Locally
abundant on upper beaches and cut banks along the Columbia River. Becoming
common along the entire length of river in Oregon and Washington” (Glad and
Halse 1993).
|
S
|
Anchusa azurea
|
Anchusa;
Common Bugloss
|
Only
one W. OR site on OFP (1/08): Polk County.
|
S
|
Artemisia absinthium
|
Absinthe
Wormwood
|
Escaping
to the north of us: common along the Columbia and Willamette rivers on dry,
sandy soils. Also at the north end of Sauvies Island.
|
S
|
Arum italicum
|
Arum
|
While
it appears to primarily be moved by humans, it occasionally is documented
away from human activity areas. Very difficult to eliminate once
established.
|
S
|
Betula pendula
|
European
White Birch
|
Widely
scattered in Fern Ridge area, West Eugene Wetlands, elsewhere. To the north
of us: Invasive and well distributed throughout the region (Multnomah &
Benton counties) on dry road cuts, disturbed soils, and in wetlands. Peach
Cove Fen, Columbia Slough, Newell Canyon, Clackamas River floodplain (all in
greater Portland area). Frequently sold commercially as an ornamental.
|
S
|
Callitriche stagnalis
|
Pond
Water-Starwort
|
Extensive
on surfaces of slow-moving water.
|
S
|
Cabomba caroliniana
|
Fanwort
|
Documented
population in Sutton Lake at Coast. From north, moving south. No inland
records yet known here.
|
S
|
Carex pendula
|
Hanging
Sedge
|
Documented
escapee in Multnomah and Clackamas counties, as well as in the Seattle area.
|
S
|
Centranthus ruber
|
Jupiter’s
Beard; Red Valerian
|
Self-seeds
readily. Self-seeding along I-5 in Douglas County.
|
S
|
Convolvulus arvensis
|
Field
Bindweed
|
Noted
away from trails in Willow Creek Natural Area. To be watched for elsewhere.
|
S
|
Cortaderia jubata
C. selloana
|
Jubata
Grass
Pampas
Grass
|
These
giant grasses (especially jubata grass) are highly invasive on the southern
coast, and are moving northward. There are a couple of inland records of
escapees, also.
|
S
|
Corylus avellana
|
European
Hazel; Filbert
|
Spread
by jays and squirrels. Occasional and most common near large orchards.
Beginning to naturalize in South Hills of Eugene
as a volunteer in yards.
|
S
|
Crataegus phaenopyrum
|
Washington
Hawthorn
|
Recently
documented as a thriving escapee in our area (Dillard Road at Hwy. 99), and
smaller populations known from Willow Creek Natural Area and EE Wilson
Wildlife Area (north of Corvallis).
|
S
|
Cymbalaria muralis
|
Kenilworth
Ivy
|
A
common escapee on shaded, moist or seepy rock faces and garden rockwork in
the Portland area. East Bank Esplanade near SE Alder and Washington, Elk
Rock, etc. Documented in Salem area, also.
|
S
|
Datura stramonium
|
Datura
|
Forming
dense patches along Willamette River at Elijah Bristow State Park.
|
S
|
Eichhornia crassipes
|
Water
Hyacinth
|
Our
warmer waters may be susceptible. Areas to the south have huge infestations.
|
S
|
Elaeagnus umbellata
|
Autumn
Olive
|
Occasional
in West Eugene hedgerows, and one site recorded in north Eugene. Other Elaeagnus
species are naturalizing in other areas.
|
S
|
Euonymus europaeus
|
European
Euonymus
|
Naturalizing
in small numbers at Patterson Slough, Eugene.
|
S
|
Galium odoratum
|
Sweet
Woodruff
|
Escapes
in and near gardens. Watch for it in natural areas.
|
S
|
Geum urbanum
|
European
Avens
|
Locally
abundant and spreading in yards, moist draws, and disturbed forests in the
West Hills of Portland (Zika and Alverson 1993; Jacobson et al. 2001).
Stephens Creek, Ash Creek, Fanno Creek, West Slope. Its occurrence seems to
be correlated with urbanization, as it is not known from open spaces outside
of the urban core. It is often mistaken for the very similar G. macrophyllum.
Also collected in Corvallis in 1995.
|
S
|
Glecoma hederacea
|
Ground
Ivy; Creeping Charlie
|
Can
become a dominant in moist, shady riparian areas. May not persist if there
is competition.
|
S
|
Hydrilla verticillata
|
Hydrilla
|
California
and Washington have costly control programs underway. A likely source is
emptying aquarium plants into waterways.
|
S
|
Hypericum calycinum
|
Ornamental
St. John’s Wort
|
Rare
escapee in Willamette Valley.
|
S
|
Inula helenium
|
Alant;
Elecampane
|
Lorane
Hwy. at Hamm Rd. (Lane Co.) and Ft. Hoskins (Benton Co.).
|
S
|
Kerria japonica
|
Kerria;
Japanese Tea Rose
|
Invasive
mostly (or entirely?) from vegetative material. Noted escaped in McKenzie
Bridge area by former USFS botanist.
|
S
|
Kniphofia uvaria
|
Poker
Flower; Red Hot Poker
|
From
dumped yard debris, long lived, makes huge dense patches, hard to eradicate.
|
S
|
Lathyrus sylvestris
|
Narrowleaf
Everlasting Pea
|
Becoming
common in S. Eugene in prairie areas (Amazon Park, Frank Kinney Park).
|
S
|
Lonicera japonica
|
Japanese
Honeysuckle
|
Just
outside residential area in two areas near Leaburg. Top of Skinner Butte:
have photo, but needs collection and keying.
|
S
|
Malus floribunda
|
Japanese
Crabapple
|
Rare
in wetlands in west Eugene.
|
S
|
Mentha ×piperita ssp. piperita
|
Peppermint
|
Large
patches in upper McKenzie and Horse Creek riparian areas.
|
S
|
Myosotis scorpioides
|
Common
Forget-Me-Not
|
Can
dominate forest understories, especially openings and on edges.
|
S
|
Nymphoides peltata
|
Yellow
Floatingheart
|
Now
established in two aquatic habitats, north and south of Springfield.
|
S
|
Paulownia tomentosa
|
Empress
Tree
|
Large
problem in the Appalachians. Occasionally seen escaping in our area:
recently, on banks of the Willamette River in Portland.
|
S
|
Pennisetum spp.
|
Fountain
Grass
|
Not
yet a problem here, but they are elsewhere.
|
S
|
Populus alba
|
White
Poplar
|
Definitely
root sprouts; suspected as spreading remotely by other means.
|
S
|
Rumex obtusifolius
|
Broad-Leaved
Dock
|
Widespread.
Invades rapidly in flooded areas on Horse Creek delta up the McKenzie River.
|
S
|
Satureja vulgaris
|
Wild
Basil
|
Spotty
distribution at present along roadsides. Large patch just N of Highway 126
on W side of Poodle Cr. Road. Seen in several other areas.
|
S
|
Sorbus aucuparia
|
European
Mountain-Ash
|
Occasional
in west Eugene wetlands and uplands. Birds spread seed.
|
S
|
Spartium junceum
|
Spanish
Broom
|
More
a problem to the south of us, but is established near top of Skinner’s Butte
on City park land.
|
S
|
Symphytum officinale
|
Comfrey
|
Scattered
reports in our area and throughout the Willamette Valley.
|
S
|
Verbena bonariensis
|
Brazilian
Verbena
|
Escaping
in Corvallis (traces), Portland, and Northern California hills. Very few
escapees documented in Eugene area to date.
|
S
|
Viburnum tinus
|
Laurustinus
|
One
vigorous Hendricks Park (Eugene) population documented. City of Eugene staff
note that it produces seedlings vigorously in landscaping bed at Skinner
Butte Park.
|
S
|
Viola odorata
|
Common
Garden Violet
|
Common
escapee from homesites into nearby forest understories.
|