North Coast Invaders

Transcription

1 North Coast Invaders

2 Why do we care about some species, and not others? Species such as scotch broom, tansy ragwort and Himalayan blackberry are already widespread Scotch broom seeds are viable for up to 80 years, depending on conditions Some, like tansy ragwort, have biological controls such as the cinnabar moth The Oregon State Weed Board maintains and updates the list of noxious weeds, their ratings, and risk assessments Priority is determined by Current distribution Plant biology Resource impacts Difficulty of detection and control

3 Garlic Mustard Alliaria petiolata Displaces native forest understory Prolific seed producer Resistant to grazing, even by slugs! Seed longevity is 5-10 years, requiring monitoring of infestation sites Basal rosette is bluish-green in color and the leaves more round Second year, flowers develop First year, basal rosette

4 Orange Hawkweed Hieracium aurantiacum Discovered in Astoria and on Nicolai Mountain in 2017 Seeds are spread by wind, boots, vehicles, animals Also spreads by runners, creates a dense mat crowding out native vegetation Very aggressive, spreads quickly even in lawns Seeds are dandelion-like and spread by wind, water, animals, clothing

5 Italian Arum Arum italicum No effective method of control, does not respond to herbicide Trials are being done with steam injection. Boiling water will kill the tuber, but this is not effective for large-scale infestations. Not currently listed in Oregon, but found recently on Hwy 53 Toxic to both humans and livestock Leaves emerge in late fall/winter and die back during the summer so all that is visible is the flower Can be confused with Calla Lily Photos from Washington State Noxious Weed Control Board

6 Giant hogweed Heracleum mantegazzianum Looks similar to cow parsnip, only much larger (over 8 feet tall) Purple spots on stalks and deeply cut leaves Umbrella-like flower head that is 2-3 feet in diameter. Compare this to cow parsnip which has a flower head of 12 or less Flower heads are only at the top of the plant. Cow parsnip will have flowers at different heights along the stem. Sap is highly toxic and causes burns and blisters

7 Yellow Archangel Lamiastrum galeobdolon Square stems and showy yellow flowers Spreads by runners and vegetative fragments (do not mow) Displaces native plants and can completely dominate forest understory Often found where people dump yard waste Patches can spread outward 3 feet per year

8 Old Man s Beard Clematis vitalba Aggressive climbing vine that can kill its host tree Feathery seedheads that are dispersed by wind and water It can re-sprout from vegetative cuttings See handout for distinguishing between invasive and native Clematis

9 Common Mullein Verbascum thapsus Common throughout the state Listed as invasive in California, not listed in Oregon Spotted in Astoria in empty lots, along driveways Once established, grows quickly to form a ground cover A single plant produces 100, ,000 seeds

10 Policeman s Helmet Impatiens glandulifera Invades riparian areas and roadsides Elongated seed heads explode, ejecting seeds Can be controlled by herbicide, mowing, or pulling Grows 3-10 tall

11 Herb Robert (hairy stems) and Shining Geranium (waxy leaves) Can be controlled by herbicide or hand pulling Invades conifer forests Cannot outcompete grasses

12 Dalmation Toadflax Linaria dalmatica Waxy green heart-shaped leaves Yellow flowers similar to snapdragon 2-3 tall Needs well-drained soils such as road edges

13 Meadow Knapweed Centauria pratensis Has been found in Columbia County Seeds could be easily transported on logging equipment Looks similar to many other knapweed species but can be distinguished by the brown brushy bracts on the flower head Can take over clearcuts, but responds well to herbicide treatment

14 Spotted Knapweed Centaurea stoebe Bluish-green foliage Pink flowers with dark-tipped bracts Very aggressive and exudes allelopathic compounds to exclude competition There are several biological controls available Has been found in 30 of the 32 counties in Oregon. Is not currently found in Clatsop county

15 Gorse Ulex europaeus In Clatsop county it is currently only found at Fort Stevens Sharp spines instead of leaves, yellow flowers Seed longevity is 10+ years depending on soil conditions 2018 Paul Busselen

16 Matgrass Nardus stricta Occurs in areas where water pools, such as pastures Densely tufted, bluish-green bunch grass Leaf blades are tightly rolled When flowering (July-September) spikelets are all on one side of the stalk

17 Yellow Flag Iris Iris pseudacorus Grows on streambanks, lakeshores and in wetlands and tidal areas Displaces native vegetation Rhizomes form large mats and can be difficult and costly to remove Fragments of rhizomes can form new colonies Exposure to leaves and rhizomes can cause skin irritation

18 Knotweed Japanese knotweed

19 Knotweed Himalayan knotweed

20 Knotweed Giant knotweed

21 Best Management Practices If you re sure it s a noxious weed, report it. Track invasive species If a new weed shows up, trace back to find out how it got there. Find out who was working in that area, and where they were working before then Take steps to stop the spread Continue to monitor the infestation areas for several years If you re working in an area with a known infestation or travel to another region: Use a boot brush Wash vehicles and equipment Clean boats, kayaks, and water toys

22 Reporting Invasive Species INVADER oregoninvasiveshotline.org Clatsop SWCD

23 Resources Institute for Applied Ecology Oregon State Weed Board King County noxious weeds webpage Or Google King County noxious weeds Washington State Noxious Weed Control Board

24 Photo Credits Oregon State Weed Board Washington State Noxious Weed Control Board Clatsop Soil and Water Conservation District Paul Busselen