Scientific Name

Common Name

Notes

Reference

Acer platanoides

Norway maple

Invasive tree spreading into forested natural areas around town including Skinner's Butte.

1

Ailanthus altissima

tree-of-heaven

Invasive tree that is problematic in City parks, alleys, and undeveloped property. This species is capable of becoming established through cracks in concrete.

1,3

Alliaria petiolata

garlic mustard

One of the most invasive forest understory plants in the east and midwest, starting to establish in the Seattle area. Documented as present in Portland and Eugene

1, 4

Betula pendula/pubescens

European birch

This species is spreading rapidly along waterways and is now established along the entirety of Amazon Creek from near its headwaters to Fern Ridge Reservoir.

5

Brachypodium sylvaticum

false-brome

Highly invasive grass rapidly spreading through forests and along rivers in our area in numerous places including Alton Baker Park. It has the potential to permanently alter the forest understory, as it outcompetes most other species and no control is known.

1, 3, 4

Buddleia davidii

fountain butterfly bush

Both butterfly bushes displace native willows which are essential host plants for native butterflies.

1, 4

Clematis vitalba

traveler's-joy

Invasive climber comparable to English ivy as a problem in areas of Portland and Seattle. Currently appearing in several areas along the Willamette with large populations established on Skinner's Butte.

1, 3, 4

Crataegus monogyna

English hawthorn

This species is welestablished and spreading rapidly into woodlands and prairies throughout town. It interbreeds with the native hawthorn creating hybrids that are difficult to accurately identify.

1, 3, 4

Cynoglossum officinale

common houndstongue

This common garden species has escaped and appears regularly in several City parks, along waterways and in unimproved alleys.

2, 3

Cytisus monspessulana

French broom

This species is a serious problem in CA and OR south coast and is now appearing in Eugene

1, 2, 3, 4

Cytisus scoparius

Scot's broom

Dense populations established along the Willamette, in the south hills, throughout the West Eugene Wetlands, along roadways and railways and in several city parks. Avoid use of all brooms.

1, 2, 3, 4

Daphne laureola

spurge laurel

Spread by birds into forested areas throughout town.

1, 3

Digitalis purpurea

foxglove

This common and attractive garden wild flower escapes easily and forms dense populations. It is becoming well established in some areas along the Willamette River.

1, 3

Geranium lucidum

shining crane's-bill

Beginning to dominate forest understories in south Eugene.

1

Geranium robertianum

herb robert

Dominates forest understories in several areas in Eugene including Hendrick's park. This species is spreading rapidly throughout town.

1, 3, 4

Hedera helix

English ivy

Spreads vegetatively in forested and open areas. Seeds spread mostly by exotic birds including starlings. This species is an extensive and widespread problem throughout Eugene, especially in forested areas and along the Willamette River.

1, 2, 3, 4

Hypericum perforatum

St. John's wort

This species invades meadows, trailsides, roadsides, and other areas throughout town.

1, 2, 3, 4

Ilex aquifolium

English holly

Spread by birds and appears regularly in forest understories throughout town.

1, 3

Iris pseudoacorus

yellow flag iris

Forms monocultures in wetlands. This species has established in Bertelsen Slough, Amazon Creek, Flat Creek, Spring Creek and along the Willamette River.

1, 3

Lathyrus latifolius

sweet, perennial or everlasting pea

Well-established, primarily along roadsides and hedgerows, large population on Chamber’s connector. Listed in "Weeds of the West"

1

Leucanthemum vulgare

oxeye daisy

This species is common in commercial "wildflower mixes". It has become widely established in meadows in West Eugene, Amazon Park, and along roadsides and mowed waterways. Formerly Chrysanthemum leucanthemum.

1, 3, 4

Linaria vulgaris

yellow toadflax

Roadside weed expanding into prairies.

1, 2, 3, 4

Lotus corniculatus

birdsfoot trefoil

Sold in pasture mixes. This species has invaded wetland areas throughout town including most drainage channels.

1, 3

Lythrum salicaria

purple loosestrife

This species forms monocultures in wetlands and is a species of national concern. Although not yet widespread, populations have been found in Amazon Creek and Willamette River and appear to be expanding.

1, 2, 3, 4

Myriophyllum spicatum

Eurasian watermilfoil

Includes water-milfoils. Myriophyllum aquaticum (M. brasiliense; parrot's feather) and M. spicatum (Eurasian milfoil) are common aquatic species in waterways and ponds throughout Eugene .

1, 2, 3, 4

Phalaris aquatica

Harding grass

This wetland species is found in slightly drier conditions than P. arundinacea. While populations are not yet as widespread as P. arundinacea, populations are rapidly expanding.

1, 3, 4

Phalaris arundinacea

reed canarygrass

This species forms dense monocultures and is one of the most widespread species in all types of wetlands throughout Eugene. It permanently and dramatically effects ecosystems where it has become established. This species is still sold commercially.

1, 3, 4

Polygonum cuspidatum (and related species and hybrids)

Japanese knotweed

This species forms riparian monocultures. This species is not yet common in Eugene but populations are becoming more common and larger. It is already a significant problem in the Portland and Seattle areas. Avoid all the large knotweeds.

1, 2, 3

Populus alba

white poplar

This species spreads rapidly via suckers and is difficult to remove once established. It also quickly becomes a hazard tree as the brittle branches are prone to breakage. This species is found is several City parks including Alton Baker Park.

3

Prunus avium

sweet cherry

This species is spread by birds into forested areas and is a quite common understory invader in forested areas throughout Eugene.

1, 3, 4

Prunus cerasifera

thundercloud plum

Grafted species and rootstocks that sucker and flower, produce fruit which is spread easily by birds. This species is appearing in prairie areas in West Eugene and woodland edges throughout town.

1

Prunus laurocerasus

English laurel

This common hedge evergreen is spread by birds and appears regularly in forested understories, especially at Skinner's Butte, Morse Ranch, and Hendrick's Park.

1, 3

Prunus lusitanica

Portugal laurel

Similar to P. laurocrasus, this species appears regularly in forest understories.

1

Prunus mahaleb

mahaleb cherry

Birds spread seeds of this species, which is common in the understories of forested areas and woodland edges throughout town.

3

Pueraria montana var. lobata

kudzu

While populations have not been found in Eugene, two occurences have been noted in the Willamette Valley. This species has devastated plant communities in southern and eastern states.

1, 2, 4

Ranunculus ficaria

lesser celandine

Highly invasive in Hendricks Park and Mt. Pisgah Arboretum. Once established populations are extremely difficult to control.

1

Ranunculus repens

creeping buttercup

This species is allelopathic. It forms large monocultures, especially in moist areas. It is common in many of our parks including Tugman Park.

1

Robinia pseudoacacia

black locust

Widely escaped east of Cascades, beginning to naturalize on West Side (Portland area, Benton County, Lane County.) This species can form woodland monocultures.

1, 3

Rosa eglanteria

sweet-briar

This species easily invades prairie areas and is common throughout town especially in West Eugene.

1, 3

Rosa multiflora

multiflowered rose

This species, similar to R. eglantaria, is a common problem in west Eugene wetlands and Fern Ridge Wildlife Area.

1

Rubus armeniacus (discolor)

Himalaya or Armenian blackberry

One of the most widespread exotic species in the Pacific Northwest. Populations are well established in all plant communities throughout Eugene.

1, 3, 4