Invasive Species

Reporting Invaders:

Help us catch early invaders! Report possible invasive species to: Oregon Invasive Species Hotline, (best option) or 1-866-INVADER (second option).

Invasives Hotline Button

Resources on Invasive Species:


Print (including field & pocket guides)

Links to Resources on Individual Weed Species:

Help us keep a lookout for these pesky species, many of which are not yet in the Long Tom Watershed or are popping up in isolated areas–and we want to keep it that way! “Early Detection and Rapid Response” (EDRR) is one of the most effective ways of managing the impacts of non-native invaders. Once an invader becomes established, it becomes very difficult to remove them, so EDRR is key!

Click on the name to navigate to information about that species at eitherODAorWestern Invasives Network.


  • False Brome by Bruce Newhouse
    Bruce Newhouse

    False Brome
    Key Features: Flat, bright green leaves; fine hairs on lower stem; lower part of leaf (called the sheath) easily pulls away from grass stem; younger plants look somewhat like a spreading spider, while oder plants form thicker mats.

    Habitat: Forest understories, along forest roads, oak savanna, and prairie

  • Garlic Mustard thumbnail
    Glenn Miller, ODA

    Garlic Mustard
    kidney or heart-shaped leaves with toothed or wavy edges; clusters of white, 4-petaled flowers in spring; pungent, garlicky odor.

    Habitat: Partial shade of woodlands (such as oak savanna); forest edges, roads, trails, edges of agricultural land, stream sides.

  • Gorse Thumbnail
    Ken French, ODA

    Key Features:
    Evergreen, densely-branched shrub; spiny or scale like leaves; Shiny, yellow flowers (resemble pea flowers).

    Habitat: Disturbed areas, logged areas, pasture land, sand dunes.

  • Hydrilla Thumbnail
    Dave Spencer

    Key Features:
    Aquatic plant forms thick mats on surface; Stems have whorls of 3-8 leaves). Resemble bottle brushes near the surface.

    Habitat: Freshwater lakes, ponds, streams, and other waterways.

  • Knotweed Thumbnail
    Glenn Miller, ODA

    Key Features: Includes several closely-related species (Japanese, Giant, and Bohemian). Leaves are heart-shaped, broad ovals with pointed tips; grows in dense thickets; flowers are greenish-white or cream-colored plumes that bloom in fall.

    Habitat: Riparian areas, waterways, and areas around human activity.

  • Lesser Celandine Thumbnail
    Tom Forney, ODA

    Lesser Celandine
    Key Features: Dark green, shiny, heart-shaped leaves form spreading carpet; yellow flowers have 5-8 petals, rising from a single stalk.

    Habitat: Moist areas along streams, ditches, and lakes; also oak woodlands, deciduous forests, and orchards.

  • Meadow Hawkweed Thumbnail
    Tom Forney, ODA

    Meadow Hawkweed
    Key Features:Bristly stems – many of them leafless; secret milky juice when crushed or broken; Up to 30 flowers appear on the stems and bloom in late spring/early summer.

    Habitat: Prairies, meadows, pastures, and lawns.

  • Old Man's Beard Thumbnail
    Tom Forney, ODA

    Old Man’s Beard
    Key Features: Woody, deciduous vine; grows rapidly – up to 95 feet; opposite, compound leaves of five leaflets; Flowers lack petals and only contain greenish-white sepals and reproductive parts.

    Habitat: Coastal, lowland areas, forest openings, and disturbed areas west of the Cascades.

  • Orange Hawkweed Thumbnail
    Jim Schultz

    Orange Hawkweed
    Key Features: Perennial herb growing about 1-3 feet tall; branches at the top to produce orange-red radial flowers blooming in summer; Broken stems may emit milky juice; Few leaves – found along base of plant.

    Habitat: Urban areas, meadows, agricultural areas, roadsides, gravel pits, forested areas, tree plantations, and along stream sides.

  • Puncture Vine Thumbnail
    Science Society
    of America

    Puncture Vine
    Key Features: Spreading, low-growing annual herb; Stems are reddish-brown that grow up to 6 feet long and produce thick mat; short, opposite leaves; fruit is a woody burr with very sharp and stiff spines.

    Habitat: Pastures, roadsides, orchards, vineyards, parks, trails, agricultural areas.

  • Purple Loosetrife Thumbnail
    ODA Plant Division

    Purple Loosetrife
    Key Features: Tall, upright, magenta flower spikes; simple, smoothed-edged leaves grow either opposite or whorled.

    Habitat: Most common in marshes or wetland areas.

  • Spanish Heath Thumbnail
    Ken French, ODA

    Spanish Heath
    Key Features: Upright, woody, evergreen shrub; up to 10 feet tall; light green, needle like leaves only 3-7 millimeters long; leaves arranged in groups of 3 or 4 whorls around the stem; flowers area conspicuous cluster of small whitish or pinkish bell-shaped flowers; blooms from December – April.

    Habitat: Coastal, forest, and pasture lands.

  • Spurge Laurel Thumbnail
    Rick Johnson,
    Thurston County

    Spurge Laurel
    Key Features: Upright, evergreen shrub about 5 feet tall; Leaves are long, dark green, and shiny above; leaves are arranged in spiral cluster around shoot tip; bell-shaped, yellow-green flowers bloom in spring.

    Habitat: Well-drained soils, shady, low-light areas; found in forests, woody parts of urban areas, and roadsides.

  • Water Primrose Willow Thumbnail
    Glenn Miller, ODA

    Water Primrose
    Key Features: Floating aquatic plant; sometimes forms mats; long, spear-shaped leaves; small, five-petaled yellow flowers.

    Habitat: Ditches, stream banks, ponds, slow moving waterways, shallow areas of lakes and reservoirs.

  • Wooly Distaff Thistle Thumb
    Ken French, ODA

    Woolly Distaff Thistle
    Key Features: Annual plant flowering in summer; grows up to about 3-4 feet tall; leaves arranged alternately on stem, long and stiff spines form on the leaves; yellow flowers form on spiny heads.

    Habitat:ÂPasture and range lands.

  • Yellow FH Thumb
    Glenn Miller, ODA

    Yellow Floating Heart
    Key Features: Aquatic perennial; roots into bottom in shallow water; floating leaves are heart-shaped or circular; bright yellow, five-petaled flowers are about 1 inch in diameter.

    Habitat: Slow moving waterways, lakes, and reservoirs.


  • bullfrog ODFW
    Photo: ODFW

    American Bullfrog
    Key Features
    : Typically green with brown spots; larger than any native frog in the Northwest (can grow over 6 inches long); long, powerful hind legs; adults have golden eyes; males loud, distinct mating call.

    Habitat: Freshwater ponds, lakes, reservoirs, sloughs, streams, and irrigation canals.

  • Chinese Mystery Snail thumb
    Photo: ODFW

    Chinese Mystery Snail
    Key Features
    : Strong shells are single-colored without bands or stripes; shells are light or dark olive green; black rounded outer lip of shell.

    Habitat: Freshwater ponds, lakes, reservoirs, sloughs, slower waterways, and irrigation ditches; prefers muddy bottoms.

  • Snapping Turtle thumb
    Photo: ODFW

    Common Snapping Turtle
    Key Features
    : Huge freshwater turtle – larger than any native Oregon turtle; dark head has larage, powerful jaws; legs and tail are thick and yellowish; dark shell varies in color.

    Habitat: Freshwater ponds, lakes, reservoirs, sloughs, slower waterways, and irrigation ditches; prefers muddy bottoms.

  • Quagga Mussel thumb
    Photo: ODFW

    Quagga & Zebra Mussels
    Key Features
    : Small – usually no more than 1 inch long; both mussels have dark black and white banded pattern on shell.

    Habitat: Most commonly freshwater lakes, reservoirs, and rivers – spread via boat traffic.

  • Red-eared Slider thumb
    Photo: ODFW

    Red-eared Slider
    Key Features
    : Greenish-gray head with red patch behind eyes; yellow or whitish line across head; top of shell is smooth and greenish gray or brown.

    Habitat: Ponds, lakes, and slow moving waterways.