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Weeds in Gardens, Landscapes & Property

Alphabetical list of common Pacific Northwest weeds on in gardens, landscapes, and property. Doesn't include weeds in lawns.

Mature boom plants with yellow flowers

Weston Miller, Oregon State University

Mature broom shrubs are three to ten feet tall with dense, slender stems and yellow flowers. Many broom shrubs often grow together.

Yellow pea family flowers

The flowers are yellow and about 1 inch long, and typical of many plants in the pea family.

Broom growing on road cut

Eric Coombs, Oregon Department of Agriculture, Bugwood.org

Broom species are nitrogen-fixing plants. This trait helps broom grow in areas with poor quality and disturbed soils.

Broom seed pods

Seed pods (fruits) are hairy along the seam and turn from green to brown as they dry.

Broom seed illustration

A mature Scotch broom plant produces about fifteen thousand seeds per year. The seeds remain viable in the soil for ten or more years.

Map of Oregon showing Scotch distribution

Scotch Broom Distribution & Reporting in Oregon

Red shows counties in Oregon where Scotch broom is widespread. Yellow shows counties where it has limited distribution. Green shows an area where Scotch broom has been eliminated. Grey areas show counties where it is not known to occur.

Reporting Invasive Species

You can help Oregon agencies track the distribution of invasive species.

If you know about an infestation of Scotch broom, please report it to the Oregon Invasive Species Hotline. Call 1-866-INVADER (1-866-468-2337). Or use the online reporting form.

Broom

Cytisus scoparius + similar species

Scotch broom and related species are evergreen shrubs with bright yellow flowers. These pea-family shrubs fix nitrogen, which helps them to invade disturbed areas. Take action to control this invasive weed.

Action Recommended
Butterfly bush infestation in a neglected urban area

Butterfly bush establishes in areas with disturbed soil. It grows along roads and riverbanks and in pastures and recently burned areas.

Butterfly bush growing out of a chimney

Butterfly bush grows in harsh conditions such as cracks in pavement and gravel roads. The photo shows a butterfly bush growing out of a chimney.

Butterfly bush leaves and flower spike

Butterfly bush’s leaves grow alternately along the stems. Leaves are 4-10 inches long and 1-3 inches wide. They are dark green on top and white-pale green underneath.

Flower spikes form at the tip of the branches. Flowers vary in color from white to purple and and blue. The flowers attract butterflies.

Mature butterfly bush flower heads

Forest and Kim Starr, Starr Environmental, Bugwood.org

Butterfly bush spreads via seeds. Seeds can form during its first year. They are viable for 3 to 5 years.

Butterfly Bush

Buddleja davidii

Butterfly bush is a common landscape shrub with attractive flower spikes. It spreads aggressively to new areas by seeds and displaces native plants. Take action to control the invasive weed.

Action Recommended
Large patch of Canada thistle before flowering

"Cirsium arvense" by Matt Lavin is licensed under CC BY 2.0.

Canada thistle grows slender stems 3-5 feet tall. Many stems grow together to form dense patches.

Canada thistle leaves

Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

Mature leaves are 2-8 inches long. Leaves are alternately arranged on the stem. They are lobed with stiff spines.

Canada thistle seed structures

Theodore Webster, USDA Agricultural Research Service, Bugwood.org

Each seed has a white structure (pappus) that aids wind dispersal. Seeds sprout on or just below the soil surface. Seeds remain viable in the soil for many years.

Canada thistle growing in a box above ground in order to show its robust root system

Canada thistle grows a large root system. The photo shows a box about 4 feet above the ground surface. A side of the box has been removed to show the roots. Roots grow laterally for dozens of feet and about 10 feet deep. The root system stores energy and supports vigorous shoot growth.

Canada thistle shoots emerging from mature roots in spring

New shoots emerge from the root system during warm periods.

Canada Thistle

Cirsium arvense

Canada thistle grows stems of 3–5 feet with pink thistle flowers. Stems die back in the winter. It regrows from robust root systems underground. It has spiny stems and the leaves limit human activity where it grows. Take action to control it.

Action Recommended
Flowering cherry laurel shrub in landscape

"Prunus laurocerasus" by wallygrom is licensed under CC BY-SA 2.0.

The photo shows a large, flowering cherry laurel shrub in a landscape.

Cherry laurel leaves and flowers

Leaves grow alternately on stems. They are leathery. The leaves are oval-shaped and 2-8 inches long. The underside of the leaves is lighter colored than the top. Flower clusters grow upright 2-5 inches tall. The white flowers have five petals.

Cherry laurel leaves and berries

Dark colored berries are about ½ inch wide. Birds eat the berries and spread the seeds.

Cherry Laurel

Prunus laurocerasus and P. lusitanica

English laurel (Prunus laurocerasus) and Portuguese laurel (P. lusitanica) are referred to as cherry laurel. Birds eat cherry laurel berries and carry seeds to new locations. Escaped cherry laurel plants are spreading from landscapes into natural areas and neglected sites. Take action to control this invasive weed.

Action Recommended
Common hawthorn thicket

iStock

Common hawthorn grows 6-30 feet tall as a thorny, deciduous small tree or shrub. It often forms a thicket.

Common hawthorn leaf

Robert Vidéki, Doronicum Kft., Bugwood.org

Leathery leaves grow alternately on stems. They are 3-7 lobed, 1-2 inches long.
Flowers occur on short stems clustered in flat-topped groups of 10-20. Each flower has five sepals and five white petals that age to light pink.

Common hawthorn flowers and leaves

Common hawthorn flowers are white or pink with five petals. The flowers have a strong odor.

Common hawthorn thorns

The thorns of common hawthorn are large and dangerous. If you are injured by a thorn, clean the wound with soap and water.

Common hawthorn leaves and berries

Fruit is a ¼- to ½-inch round, and dark red to crimson that persists into late winter.
Birds eat the fruits and spread the seeds.

Common Hawthorn

Crataegus monogyna

Common Hawthorn was planted in landscapes and hedgerows. It is now spreading into natural areas and neglected sites. It has sharp thorns that cause injury. Take action to control this invasive plant.

Action Recommended
Creeping buttercup leaves

iStock

Creeping buttercup flower

Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

Creeping Buttercup

Ranunculus repens

Creeping buttercup is a perennial (lives many years), herbaceous plant (soft leaves and stems) with yellow flowers. It is a widespread weed in the Pacific Northwest, especially west of the Cascade Mountains.

Action Highly Recommended
Dandelion plant

Elekes Andor, CC BY-SA 4.0, via Wikimedia Commons

Leaves and flowers grow from a tap root. Yellow flowers grow 1-2 inches wide.

Closeup view of dandelion leaf

Lynn Sosnoskie, University of Georgia, Bugwood.org

Jagged leaves grow 2-10 inches long and look like lion teeth.

Dandelion puffball or seedhead composed of seeds

Joseph O'Brien, Joseph O'Brien, Bugwood.org

Flowers mature into a ball of seeds. The seeds detach and float away.

Dandelion

Taraxacum officinale

Plants are low-growing with yellow flowers that form balls of seeds. Dandelion is a very common weed. Action is optional.

Action Optional
English holly leaves with spines

English holly has waxy, evergreen leaves with spines along the edges. Wear thick gloves and clothing to handle holly plants. The spines hurt.

English holly leaves and red berries

Red holly berries are about 1/4 inch in diameter. Birds eat the berries and spread the seeds.

Holly cultivar with variegated leaves

John Ruter, University of Georgia, Bugwood.org

There are numerous cultivars of English holly with distinct traits. The photo shows a cultivar with variegated leaves.

English Holly

Ilex aquifolium

English holly is a common landscape plant used for hedges and screens. It grows 20–50 feet tall as a compact tree. Holly is also pruned as a hedge. Birds eat English holly berries and carry seeds to new locations. Escaped English holly plants are spreading from landscapes into natural areas and neglected sites. Take action to control its spread.

Action Recommended
False brome plant

Michelle Delepine, West Multnomah Soil & Water Conservation District

False brome germinates in late fall and spring. Plants mature into compact bunches of bright-green leaves throughout spring, summer, and fall. Plants remain green in mild winter temperatures, and in some colder winter locations, the leaves and stems die and become white thatch.

False brome leaf blade

"brachypodium sylvaticum" by Miguel Porto is licensed under CC BY-NC 4.0.

Individual false brome plants produce dozens to hundreds of seeds. Seeds are spread by animals, people, or equipment that move through infested areas. Most seeds germinate within a year or two.

False brome flowers

False brome flowers in summer. Groups of flowers grow in pale green, drooping spikelets that are attached directly to the flowering stem. Spikelets are 1-2 inches long. There are 5-10 spikelets per flowering stem, as shown in the photo. Each spikelet has 7-17 individual flowers.

False brome in forest clearing

False brome is expanding quickly in closed-canopy forests, woodlands, oak savannah, grasslands, roadside trails, and disturbed areas.

It degrades habitat by suppressing native plant understory growth.

Map of Oregon showing false brome distribution

False Brome Distribution & Reporting

Red areas show Oregon counties where false brome is widespread. Yellow areas show counties where it has limited distribution. It is not known to occur in the grey areas.

Reporting in Oregon

You can help Oregon agencies track the distribution of invasive species.

If you have false brome growing on your property, please report it to the Oregon Invasive Species Hotline. Call 1-866-INVADER (1-866-468-2337). Or use their online reporting form.

False Brome

Brachypodium sylvaticum

False brome is an invasive, long-lived (perennial) grassy weed. This bunchgrass spreads quickly by seed. It forms dense stands that suppress other plants. False brome is expanding rapidly in a variety of habitats in the Pacific Northwest. Take action to report and control it.

Action Highly Recommended
Field bindweed flowers and leaves

telev_cat, iStock

Field bindweed forms a dense mat of vines and leaves on the ground. It also climbs and overtakes other plants, fences, and trellises.

Field bindweed leaves and flower on a stem compared to ruler

Bruce Ackley, The Ohio State University, Bugwood.org

Field bindweed forms a dense mat of vines and leaves on the ground. It also climbs and overtakes other plants, fences, and trellises.

Pink and white field bindweed flowers

"serprud-024" by Vlad Proklov is licensed under CC BY-NC 2.0.

Field bindweed spreads with vines that grow across the ground and roots underground.

Field bindweed  plants with root system and daughter plants

Field bindweed spreads with vines that grow across the ground and roots underground.

Field bindweed seeds

Mature field bindweed plants produce dozens to hundreds of seeds shown in the photo. Seeds remain viable in the soil for many decades.

Field bindweed seeds compared to ruler (millimeter scale)

Bruce Ackley, The Ohio State University, Bugwood.org

Mature field bindweed plants produce dozens to hundreds of seeds shown in the photo. Seeds remain viable in the soil for many decades.

Field Bindweed

Convolvulus arvensis

Field bindweed is a perennial (long-lived) plant that dies back to the ground in the winter. This herbaceous (soft stems and leaves), vining plant has white-to-pink flowers. It forms dense mats that cover the ground. It also climbs and smothers crops and ornamental plants.

Action Recommended
Garlic mustard plant in bloom

Chris Evans, University of Illinois, Bugwood.org

Stems grow from three to four feet tall and wide. White flowers form at the top of the stems in the spring.

Garlic mustard rosettes

Tom Heutte, USDA Forest Service, Bugwood.org

Seeds germinate in the late winter or early spring and grow into rosettes with kidney-shaped, toothed leaves. Individual plants live as rosettes one year.

Garlic mustard flowers and leaves

Garlic mustard plants live for two years. In the spring of its second year garlic mustard grows stems and triangular leaves with toothed edges. The leaves are arranged opposite each other along the stem. White flowers with four petals grow at the top of the stems.

Garlic mustard pods

Garlic mustard spreads quickly by seed. Larger, mature plants make up to eight thousand seeds. The seeds form in narrow pods in the late spring. By late June, the seed pods pop open, and spread the seeds.

Garlic mustard growing in a forest

Garlic mustard quickly dominates natural areas such moist forests and dry woodlands. It suppresses native plant growth. The loss of native plants reduces the habitat value of the area.

Map of Oregon showing garlic mustard distribution

Garlic Mustard Distribution and Reporting in Oregon

The red area on the map shows where garlic mustard is widespread. Yellow areas show counties where it has limited distribution. Grey areas show counties where it is not known to occur.

Reporting Invasive Species

You can help Oregon agencies track the distribution of invasive species.

If you know about an infestation of garlic mustard, please report it to the Oregon Invasive Species Hotline. Call 1-866-INVADER (1-866-468-2337). Or use their online reporting form.

Garlic Mustard

Alliaria petiolata

Garlic mustard is an invasive, herbaceous plant (soft leaves and stems) that spreads by seeds. It forms a dense stand of plants and dominates the forest understory and edges. Take action to control this invasive weed.

Action Highly Recommended
Giant hogweed flowers

Terry English, USDA APHIS PPQ, Bugwood.org

Have white, umbrella-like, flowerhead (umbels) that are 18-24 inches across

Hollow stem is covered with dark purple blotches, bumps and hairs

Stems are 2-4 inches in diameter and hollow. Have purplish-red blotches and bumps. Covered with stiff hairs.

Dense patch of giant hogweed plants before flowering

Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

Forms dense patches that emerge in later winter and spring. Stems die and remain standing late summer through early winter.

Giant Hogweed

Heracleum mantegazzianum

Giant hogweed plants often reach 10–12 feet tall. The white flowers grow 8–24 inches across. Leaves are 3–5 feet wide, coarsely toothed, with deeply cut leaflets. Giant hogweed sap on your skin or eyes causes severe burns when exposed to sunlight. Report this invasive species if you think you’ve found it on your property. Giant hogweed is an Early Detection Rapid Response species. An agency can help yo u control it on your property.

Action Highly Recommended
Gorse stem with spines and yellow flowers

Daria Trefilova, iStock

Mature gorse shrubs are three to ten feet tall with dense, slender stems and yellow flowers. Many gorse shrubs often grow together.

Gorse flowers on stem

Eric Coombs, Oregon Department of Agriculture, Bugwood.org

The flowers are about one inch long and typical of many plants in the pea family.

Gorse stem with spines

Gorse spines are large and dangerous. If you are injured by a gorse spine, clean the wound with soap and water.

Gorse

Ulex europaeus

Gorse is an evergreen shrub (bush) with sharp thorns and bright-yellow flowers. These pea-family shrubs fix nitrogen, which helps them to invade disturbed areas. Take action to control this invasive weed.

Action Highly Recommended
Hedge bindweed growing on fence

Robert Vidéki, Doronicum Kft., Bugwood.org

Hedge bindweed forms a dense mat of vines and leaves on the ground. It often climbs and overtakes other plants, fences, and any adjacent structure.

Hedge bindweed leaves and stems (vines)

"Calystegia sepium" by dhobern is licensed under CC BY 2.0.

Mature plants have triangular or arrow-shaped leaves that range from 2-5 inches long.
The bottom of hedge bindweed leaves are squared off or rounded compared to field bindweed. The vines are often reddish-tinged and grow up to 10 feet long.

Pink and white hedge bindweed flowers

Hedge bindweed spreads by vines supporting flowers that are 2.5-5 inches long and 1-2 inches wide. Look for flowers in late spring throughout summer. The flowers produce 2-4 grey-to-brown-black seeds that persist for decades in the soil.
Hedge bindweed also spreads by rhizomes.

Hedge bindweed rhizome and root system

Salicyna, CC BY-SA 4.0, via Wikimedia Commons

The photo shows a hedge bindweed plant with rhizomes sprouting new above-ground shoots.
Hedge bindweed’s root system may spread horizontally up to 10 feet and many feet deep. The extensive root system allows the plant to avoid drought conditions. Look for seedlings and shoots from mature plants in early spring.

Hedge bindweed seeds compared to ruler (millimeter scale)

Ken Chamberlain, The Ohio State University, Bugwood.org

Hedge bindweed plants produce dozens to hundreds of seeds shown in the photo. Seeds remain viable in the soil for decades.

Hedge Bindweed

Calystegia sepium

Hedge bindweed is a perennial (long-lived) plant that dies back to the ground in the winter. This herbaceous (soft stems and leaves), vining plant has white-to-pink flowers. Hedge bindweed spreads by seed and root fragments. Individual plants spread with an extensive underground root system.

Action Recommended
Himalayan blackberry thicket in abandoned area

Himalayan blackberry takes over neglected areas. Plants live for many years (perennial). Canes grow up to 15 feet tall. They grow on the ground or through vegetation or structures.

Red-colored Himalayan blackberry cane with large thorns

Himalayan blackberry thorns are large and dangerous. If you are injured by a blackberry thorn, clean the wound with soap and water.

Himalayan blackberry fruits, leaves, and stems

Eric Coombs, Oregon Department of Agriculture, Bugwood.org

Birds and mammals eat the berries and spread seeds widely.

Himalayan blackberry leaflet with five leaves

 Leaves are palm-shaped with a central stem. Each leaf has five leaflets (sometimes three) with toothed margins.

Himalayan blackberry flower and leaves

Himalayan blackberry flowers have five petals in shades of white to pink. They are very attractive to honey bees and other pollinators.

Himalayan Blackberry

Rubus bifrons. R. armeniacus

Invasive Himalayan blackberry is a widespread plant that grows in neglected and natural areas throughout the Pacific Northwest. Canes have sharp thorns and form dense thickets. Take action to control Himalayan blackberry and limit its spread.

Action Recommended
Dense patch of field horsetail

Horsetails and scouring rushes often grow in dense patches along stream banks, roadsides and irrigated areas. Plants spread underground with robust rhizomes and tubers. They thrive with full sun and moist soil. After plants are established they will tolerate seasonally dry soil. Horsetail is toxic to livestock when they eat large quantities or eat it regularly.

Fertile stems of field horsetail

Field horsetail grows cream-to-tan colored fertile stems in spring to early summer. They are unbranched, leafless and up to 12 inches tall. At the top is a cone-like structure that produces spores. These stems die after spores are released.

Closeup of stem with thin whorled leaves

Shaun Winterton, Aquarium and Pond Plants of the World, Edition 3, USDA APHIS PPQ, Bugwood.org

The jointed stems of horsetails grow distinctive thin leaves in whorls at each joint.

Horsetail

Field horsetail (Equisetum arvense), giant horsetail (E. telmateia), scouring rush (E. hyemale)

Horsetail, scouring rush and many other Equisetum species are Pacific Northwest natives. They grow throughout the region. Plants live for many years and are often found in wet or seasonally wet areas. The most common species are field horsetail (Equisetum arvense), giant horsetail (E. telmateia), and scouring rush (E. hyemale).

Action Optional
Italian arum plants with stems and leaves

Weston Miller, Oregon State University

Plants grow about 12–18  inches tall. Leaves are shaped like an arrow with a pale green midrib and veins.

Italian arum flower and leaves

"Arum italicum - Araceae" by Kerry  Woods is licensed under CC BY-NC-ND 2.0 (cropped).

Flowers are a yellow-cream color and unpleasant smelling. They have a stubby spike and a large, white, funnel-shaped structure.

Italian arum spikes with green fruit in bare soil

Fruits are tightly clustered on spikes. Fruits turn from green to orange-red, and contain seeds that spread it to new areas.

White roots and stems exposed in soil

Stems extend below the soil surface. Forms white tubers and roots. They are difficult to remove.

Dense patch of Italian arum

Italian arum forms dense patches that are visible in fall through winter. In warm, dry summer months, the stems and leaves die back and are not visible above ground.

Italian Arum

Arum italicum

Plants grow about 12–18 inches tall. Leaves are shaped like an arrow with a pale green midrib and veins. Italian arum escaped from landscapes and is spreading into new areas. Take action to control this invasive weed.

Action Highly Recommended
Knotweed leaves and stems

David J. Moorhead, University of Georgia, Bugwood.org

The leaves grow opposite one another along the red stems.

Knotweed leaves and flower

Barbara Tokarska-Guzik, University of Silesia, Bugwood.org

Leaves grow as long as 15 inches and 11 inches in width. But leaves can be smaller, as shown in the photo.

Knotweeds plant with many flowers

Flowers are abundant in mid to late summer. They grow on branches in the top 1/3 of the plant. Flowers make seeds that result in new plants. But seedlings play a small role in establishing new stands.

Knotweed clump with many stems

Jan Samanek, Phytosanitary Administration, Bugwood.org

Stems are long, hollow, and segmented like bamboo. They grow from 4-15 feet tall and are often arched.

Knotweed root structure

John Cardina, The Ohio State University, Bugwood.org

Knotweed spreads far beyond shoot growth with underground root structures (rhizomes). Stems and root pieces broken or cut away from rooted plants can make new plants.

Knotweed stand with dead stems in dormant season

Barbara Tokarska-Guzik, University of Silesia, Bugwood.org

In the fall and winter, knotweed stems die and remain standing. New growth emerges from the soil in early spring.

Knotweed

Fallopia sachalinensis , F. x bohemica , F. japonica & Persicaria wallichii

Knotweeds are a group of related, invasive plant species. They are shrub-like, broadleaf plants that die back in the winter. Knotweed plants grow 4–15 feet tall each year. They have large, oval-to-heart-shaped leaves. Take action to report and control knotweed.

Action Highly Recommended
Dense patch of of lesser celandine with flowers

Forms dense patches that are visible in later winter and spring. Above-ground stems die back and are not visible during summer and fall.

Lesser celandine plants with roots and stems next to ruler

David L. Clement, University of Maryland, Bugwood.org

Plants grow about 6-8 inches tall from the base (rosette).

Yellow flower with 8 yellow sepals

Yellow flowers have yellow sepals (resemble petals).

Small, pale bulbs on stems

Small, pale, bulbs (called bulbils) form on the stems. They attach to your shoes, clothes, and equipment. Bulbils are carried by flowing water to new areas.

 

Lesser Celandine

Ficaria verna

Lesser celandine grows 6–8 inches tall. It has dark-green leaves shaped like hearts, and yellow flowers. Lesser celandine spreads quickly. It dominates an area when left unmanaged. Take action to control this invasive weed.

Action Highly Recommended
Poison hemlock leaves and stems 

Barry Rice, sarracenia.com, Bugwood.org

In the first year poison hemlock is a rosette of glossy-green leaves about 2-3 feet high. The leaves are smooth and hairless.

Poison hemlock stems with purple blotches

In spring of the second year of growth, established plants sprout hollow flowering stems. They display red-purple spots and have a sheath at the base of the side stems. They grow up to 12 feet tall. The plants have an unpleasant odor and toxic fluid when crushed.

Poison hemlock flowers

Eric Coombs, Oregon Department of Agriculture, Bugwood.org

Poison hemlock has white, umbrella-like flowerheads (umbels) that are 4-8 inches across.
 

Poison Hemlock

Conium maculatum

Poison hemlock is found throughout the Pacific Northwest. It grows in streams, ditches, roadsides, forest edges, and cultivated fields. Poison hemlock can dominate an area when left un-managed. All parts are poisonous for people, pets, and livestock. Control this plant in landscape and pasture areas. 

For more information about poison hemlock and livestock, see Poison hemlock and Western waterhemlock: deadly plants that may be growing in your pasture - OSU Extension Service

Action Recommended
Poison oak leaves

The leaves of poison oak alternate along the stem. They have three leaflets that can have smooth or lobed edges. The leaves are often shiny. They are purplish brown when they first emerge. They turn green when fully developed.

Poison oak vines growing up tree

Joseph M. DiTomaso, University of California - Davis, Bugwood.org

Poison oak grows as a shrub, or as a vine on trees and  structures. The vines can also run along the ground.

Red poison oak leaves in the fall

Joseph M. DiTomaso, University of California - Davis, Bugwood.org

In the late summer and fall, leaves turn orange and red.

Poison oak

Toxicodendron diversilobum

Poison oak is native to the Pacific Northwest. It grows mostly in western Oregon and Washington. It is a woody shrub or vine that loses its leaves in the winter. It is often found in woodlands, grassy hillsides, and chaparral in drier locations.
The leaves and stems contain an oil called urushiol. It causes a painful, itchy skin reaction (dermatitis) for many people. About 10-15 percent of people don’t react to poison oak oil. Touching clothes, tools, and pets that have urushiol on them can also result in dermatitis.

Action Optional
Common Pokeweed with red stems, green unripe berries

Weston Miller, Oregon State University

Pokeweed often matures into a shrub or small tree. But it is not woody and dies back with the onset of winter.

Red pokeweed stem

Karan A. Rawlins, University of Georgia, Bugwood.org

Stems grow two to eight feet each year from a white, fleshy root. They are colored green, red, or purple. The hollow stems are smooth and grow up to 4 inches across.

Pokeweed leaves

Each leaf is 5-20 inches long. The leaves are about one third as wide as they are long. They alternate along the stem. The leaves smell bad when crushed.

Dark-purple pokeweed berries

The flowers mature into green berries. In late summer or early fall, berries turn dark purple. The berries occur as a drooping bunch that resembles a grape cluster. Berries are poisonous. Do NOT eat the berries.
Birds eat the berries and scatter the seeds. New plants grow from the seeds.

Cluster of pokeweed shoots

Ohio State Weed Lab, The Ohio State University, Bugwood.org

Pokeweed seedlings have alternate leaves. The leaves are red on the underside.

Shoots emerge from established root crowns in the spring. The shoots resemble seedlings, but are thicker and clustered together as shown in the photo.

Pokeweed

Phytolacca americana

Pokeweed may mature into a shrub or small tree, but it is not woody and dies back with the onset of winter. The crushed leaves have a strong, unpleasant odor. All parts of pokeweed are poisonous to people, pets, and livestock. Take action to report and control pokeweed.

Action Highly Recommended
Shiny geranium growing in a dense stand on road side

Weston Miller, Oregon State University

Shiny geranium grows six to eighteen inches tall. It often forms dense mounds that smother other vegetation. It favors landscapes and the sides of roads, trails, and forest edges.

Shiny geranium plant with red stems

Stems range from green to red, depending on environmental conditions. The stems are hairless.

Stand of geranium plants with red leaves

Weston Miller, Oregon State University

Plants turn red in the late spring and into summer. The green structures are mature flowers (capsules) that contain shiny geranium seeds.

Shiny geranium seed capsules and seeds

Shiny geranium forcefully ejects its tiny seeds from their capsules. This trait helps spread the seeds to form dense carpets. The seeds are textured. They stick to shoes, clothing, and pets. The seeds are carried to new areas.

Map of Oregon showing shiny geranium distribution

Shiny Geranium Distribution & Invasive Species Reporting in Oregon

Red areas show Oregon counties where shiny geranium is widespread. Yellow areas show counties where it has limited distribution. Grey areas show counties where shiny geranium is not known to occur.

Invasive Species Reporting

You can help Oregon agencies track the distribution of invasive species.

If you know about an infestation of shiny geranium, please report it to the Oregon Invasive Species Hotline. Call 1-866-INVADER (1-866-468-2337). Or use their online reporting form.

Shiny, lobed leaves and pink flowers

The leaves are shiny and lobed. Shiny geranium has small, pink flowers with five petals.

Shiny Geranium

Geranium lucidum

Shiny geranium grows 6–18 inches tall. It has shiny leaves and pink flowers. Shiny geranium spreads quickly in shaded woodlands and yards. Take action to control this invasive weed.

Action Highly Recommended
Flowering tansy ragwort plants in field

Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

Tansy ragwort stems grow 1.5-4 feet tall. It forms dense stands. Tansy ragwort thrives in areas with disturbed soil.

Examples of tansy ragwort leaves

Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

Its leaves are dark green on top and lighter underneath. They have deeply lobed leaves with a ruffled look.

Tansy ragwort flowers

Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

Tansy ragwort has yellow, sunflower-family flowers. They have 15-ray flowers that look like petals.

Tansy ragwort rosette

After a tansy ragwort seed germinates, plants form a rosette. The rosettes have light-green leaves that grow close to the ground. The leaves are lobed.

Cinnabar moth larvae on tansy leaf

The cinnabar moth (Tyria jacobaeae) was introduced to the Pacific Northwest. It helps to control tansy ragwort. The larvae of the moth defoliate tansy ragwort. See below for information about biocontrol.

Tansy Ragwort

Senecio jacobaea

Tansy ragwort is an herbaceous plant (soft stems and leaves) with yellow flowers. The stems grow upright 0.5–4 feet tall. It is a widespread weed in the Pacific Northwest. It is common in areas disturbed by grazing, logging, construction, or fire. Take action to control tansy ragwort.

Action Highly Recommended
Many tree-of-heaven stems growing in abandoned building foundation

Joseph M. DiTomaso, University of California - Davis, Bugwood.org

Tree-of-heaven is a fast-growing deciduous tree. It grows as a single tree or as many stems as shown in the photo.

Large tree-of-heaven leaf with leaflets

Karan A. Rawlins, University of Georgia, Bugwood.org

Leaves have a large central stem with leaflets arranged opposite each other along the stem. A single leaf is 1-3 feet long.

Tree-of-heaven fruits hanging on branch

Annemarie Smith, ODNR Division of Forestry, Bugwood.org

Established female trees produce hundreds of thousands of seeds each year. The seed forms inside clusters of samaras (seed pods). They remain on the tree through winter.

Textured bark of mature tree-of-heaven tree

Mature trees grow as a single trunk up to 100 feet tall. Bark is textured and colored shades of brown and grey as trees age.

Many tree-of-heaven stems in grassy area

Tree-of-heaven has an extensive root system, including shallow roots. The shallow roots produce many shoots that emerge far from the trunk of the established tree.

Tree-of-heaven distribution in Oregon

Tree-of-Heaven Distribution & Invasive Species Reporting in Oregon

The yellow areas on the map of Oregon show counties where tree-of-heaven has limited distribution. Grey areas show counties where it is not known to occur.

Invasive Species Reporting

You can help Oregon agencies track the distribution of invasive species.

If you know about an infestation of tree-of-heaven, please report it to the Oregon Invasive Species Hotline. Call 1-866-INVADER (1-866-468-2337). Or use their online reporting form.

Spotted lanternfly adult

INVASIVE SPECIES ALERT: Spotted Lantern Fly

This invasive insect feeds on tree-of-heaven and damages many agricultural crops. It is established in the Eastern United States. It is not known to occur in the Pacific Northwest at this time. Look for this insect pest and if you find it, report it. Learn more.

Tree-of-Heaven

Ailanthus altissima

Tree-of-heaven is an invasive tree that spreads quickly. It is very difficult to control. It grows an extensive root system, which produces new stems that emerge far away from the trunk of established trees. Take action to control tree-of-heaven.

Action Highly Recommended
Yellow archangel stems, leaves, and flowers

Yellow archangel’s leaves are hairy and toothed. They grow opposite each other along the stem. Its leaves are often variegated with silver green markings

Yellow archengel leaves (green) and flowers

Rob Routledge, Sault College, Bugwood.org

Some yellow archangel plants have green leaves. All plants of this species have yellow flowers as shown in the photo.

Stem layering illustration

University of Maine

Once yellow archangel is established, it spreads via stem layering. When nodes on the stem contact the ground or get buried, they sprout roots. The line drawing shows layering. Stem fragments can also take root and establish new plants. Yellow archangel also spreads by seed.

Yellow Archangel

Lamiastrum galeobdolon

Yellow archangel is a fast-growing perennial (lives many years) herbaceous plant (soft leaves and stems). It was widely planted in landscapes the Pacific Northwest. It has escaped from landscapes and is quickly spreading into adjacent forested areas. Take action to control this invasive weed.

Action Highly Recommended
Clump of yellow flag iris leaves

John Ruter, University of Georgia, Bugwood.org

The mature leaves are 2–3 feet long, flattened and sword-shaped, typical of most iris. They may stay evergreen in mild winters.

Yellow flag iris flower

Yellow iris (Iris pseudacorus) by Evelyn Simak - geograph.org.uk/p/6172667 is licensed under CC-by-sa/2.0.

Yellow flag iris flowers have 3 large downward-spreading sepals and 3 small erect petals. The sepals may have delicate brownish to purple veins. Yellow color may be bright or pale. It blooms from late spring into summer.

Glossy green seed pod

Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

The seed pod is up to 4 inches long and glossy green. It contains many flattened brown seeds. Seeds float on the water, and spread yellow flag iris into the surrounding area.

Rhizome with leaves and roots

Joseph M. DiTomaso, University of California - Davis, Bugwood.org

Yellow flag iris spreads by stout rhizomes. They grow rapidly, forming a dense mat.

Brown, flattened seeds

Steve Hurst, USDA NRCS PLANTS Database, Bugwood.org

Flattened brown seeds are about ¼ inch in diameter.

Yellow Flag Iris

Iris pseudacorus

Yellow flag iris is an invasive plant. It was introduced to the Pacific Northwest in ornamental water gardens, erosion control projects, and sewage treatment ponds. It spreads quickly, forming dense stands in shallow water and wet soil. Yellow flag iris is is toxic to livestock. Take action to control this invasive plant and prevent its spread.

Action Highly Recommended
Yellow starthistle flower and spines

"St Barnabys Thistle" by John Tann is licensed under CC BY 2.0.

Flowers are bright yellow with long, sharp spines at the base.

Gray-green yellow star thistle stems

Steve Dewey, Utah State University, Bugwood.org

Stems are gray-green. The extended leaf bases make the stems appear winged.

Yellow starthistle rosette

Cindy Roche, Bugwood.org

Yellow starthistle forms a rosette after germinating. Plants in this stage grow a large taproot.

Yellow starthistle plants growing in dense stand

Yellow starthistle plants grow in dense stands from 6 inches to 5 feet tall.

Yellow starthistle seeds

Yellow starthistle plants can produce thousands of seeds. Up to 95% of seeds are viable. Seeds remain viable in the soil for 3 or more years.

Yellow Starthistle

Centaurea solstitialis

Yellow starthistle grows spreading stems from 6 inches to 5 feet tall. Its stems are gray-green. It forms yellow flowers with sharp spines at the base. Yellow starthistle’s prickly flowers hurt and limit access to areas. Take action to control it.

Action Highly Recommended