JAPANESE KNOTWEED GIANT KNOTWEED. Habitat Preference: Description: Herbaceous perennial shrub growing. Height Up to 12 ft. tall

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3 JAPANESE KNOTWEED Polygonum cuspidatum (Fallopia japonica) BE ON THE LOOKOUT FOR THIS INVADER! Habitat Preference: Roadsides River Banks Wetlands Wet Depressions and Woodland Edges Photo: Randy Westbrooks,U.S.GeologicalSurvey,Bugwood.org Height Up to 12 ft. tall GIANT KNOTWEED Polygonum sachalinese Description: Herbaceous perennial shrub growing from 3-10 ft. in height (Japanese knotweed) or up to 12 ft. (Giant knotweed); deep taproot with surface roots that extend laterally from ft. Tip of the Mitt Watershed Council Funding provided by: Petoskey-Harbor Springs Area Community Foundation

4 STEM AND LEAVES Photo: K. Beyer Photo: K. Beyer IDENTIFICATION Leaves: Simple, alternate and broad, typically growing up to 6 in. long and 5 in. wide with an abruptly pointed tip and a flat or tapering base (Japanese knotweed) and 6-12 in. long and 2/3 as wide with a shallow, heart-shaped base (Giant knotweed). Stems: Upright, round, hollow, and often mottled, with a fine whitish coating that rubs off easily. Resembles bamboo. FLOWERS Photo: K. Beyer Photo: K. Beyer Flowers: Numerous, small, white or greenish flowers on a slender stalk in leaf axils and stem tips; bloom August- September. Fruit and Seeds: Fruits are three-winged; seeds are dark and glossy; wind and water dispersed. TREATMENT: Monitor ditches, paths, roadways, etc. Resprouts vigorously after cutting, mowing, tilling and digging. Tiny fragments of roots and stem nodes can sprout and form new colonies-remove all cut plant materials and incinerate or place in landfill. Repeated foliar herbicide application may provide effective control. Cutting early in the season and then spraying later preferable as plants will still be short enough to spray with minimal non-target impact. Follow-up required for years. For additional information and full treatment option descriptions, visit

5 LEAFY SPURGE Euphorbia esula BE ON THE LOOKOUT FOR THIS INVADER! Habitat Preference: Roadsides Prairies Savannas Gravel Pits Open areas Photo: Norman E. Rees, USDA Agriculture Research Service - Retired, Bugwood.org Height 6-36 in. tall Description: Herbaceous perennial ranging in height from 6-36 in.; root system can extend up to 20 ft., with lateral roots near the surface. Tip of the Mitt Watershed Council Funding provided by: Petoskey-Harbor Springs Area Community Foundation

6 LEAVES AND STEMS Photo: John M. Randall, The Nature Conservancy, Bugwood.org IDENTIFICATION Leaves: Simple, alternative, narrow, bluish green; usually pointed and drooping with smooth magins; exude white milky sap when crushed. Leafs out early in spring; bright yellow-green bracts appear in late May or early June. Stems: Upright stems that branch towards the top of the plants; dry stems may persist into the winter and following summer; stems also release white, milky sap when broken. FLOWERS STEMS Photo: Norman E. Rees, UDSA Agriculture Research Service - Retired, Bugwood.org Photo: Chris Evans, Illinois Wildlife Action Plan, Bugwood.org Flowers: Small, yellowish-green flowers with fused petals forming a cuplike structure; bloom mid-june to late-july. Fruit and Seeds: Smooth, oblong, graybrown seeds in explosive capsules; one plant can produce up to 200 seeds; high germination rate; viable up to 8 years with adequate moisture. TREATMENT: Long shoots spread laterally-pulling, digging, burning and tilling may cause them to increase. Foliar herbicide treatment provides effective control of small infestations. Surveillance and control efforts needed for 5-10 years. For additional information and full treatment option descriptions, visit

7 EURASIAN PHRAGMITES Phragmites australis subsp. autralis BE ON THE LOOKOUT FOR THIS INVADER! 14 Habitat Preference: Wetlands Ditches Stream and Pond Banks Tolerates road salt Height Up to 14 ft. tall Description: Stout, warm-season perennial grass ranging in height from 6-13 ft. Forms dense, impenetrable stands, in contrast with the native subspecies, which occurs in a colony of scattered stems. Spreads easily and extensively by seed; also by an extensive, aggressive system of horizontal and vertical roots (rhizomes) that can live for 3-6 years. Tip of the Mitt Watershed Council Funding provided by: Petoskey-Harbor Springs Area Community Foundation

8 IDENTIFICATION FLOWERS AND SEEDS LEAVES AND STEMS Leaves: Flat, smooth leaf blades: in. long, in. wide. Leaf sheaths stay attached even after stem dies. Stems: Upright; rigid and hollow; dull yellowish, covered by leaf sheaths. Flowers: Dense branched clusters at the end of each stem, becoming open and feathery at maturity. Fruit and Seeds: Seeds with white hairs below that are almost as long as the seed; abundant seeds. Photos: K. Beyer TREATMENT: Monitor wetlands, ditches and moist sites, particularly adjacent to areas that receive nutrient rich runoff or road salt. Burning, mowing, dicing and digging stimulates populations. Foliar herbicides should be used in late summer or fall. For additional information and full treatment option descriptions, visit

9 PURPLE LOOSESTRIFE Lythrum salicaria BE ON THE LOOKOUT FOR THIS INVADER! 6 Photo: Wikimedia.com - Boxborough, Mass. Habitat Preference: Disturbed wet areas, can tolerate up to 50% shade. Height ft. tall Description: Herbaceous perennial, ft. tall; strongly developed taproot becomes woody with age. Spreads vigorously in moist soil conditions. Very persistent. Crowds our native wetland plant species. Tip of the Mitt Watershed Council Funding provided by: Petoskey-Harbor Springs Area Community Foundation

10 IDENTIFICATION LEAVES AND STEMS FLOWERS Leaves: Pointed or linear shape; opposite or spiraled around stem; flat to somewhat curved; 1-4 in.; larger leaves at the base. Stems: Square; smooth or fine-haired. Flowers: Numerous, purple with 5-7 petals; spike-like flowers, two or more per plant; bloom July through October. Fruit and Seeds: Seed pod, small, abundant seed production. Photos: K. Beyer TREATMENT: Galerucella beetles are the best control for large populations. Small populations may be eradicated with herbicides, or by hand-pulling seedlings, remove all flower and seed heads. Galerucella beetle For additional information and full treatment option descriptions, visit

11 REED CANARYGRASS Phalaris arundinacea BE ON THE LOOKOUT FOR THIS INVADER! Up to 8 Photo: Leslie Habitat Preference: Wetlands Ditches Stream and Pond Banks Wet Meadows J. Mehrhoff, University ofconnecticut,bugwood.org Height ft. tall Description: Cool-season, perennial grass ranging in height from ft.; forms dense stands; root system is a thick, fibrous mat. Originally planted for erosion control because of its vigorous growth and drought tolerance. Most visible in spring when inflorescences (flowers) expand to facilitate pollination. Tip of the Mitt Watershed Council Funding provided by: Petoskey-Harbor Springs Area Community Foundation

12 LEAVES AND STEMS Photo: Leslie J. Mehrhoff, University of Connecticut, Bugwood.org IDENTIFICATION Leaves: Flat, rough leaf blades, in. wide and up to 1.5 ft. long. Stems: Upright; bluish-green in color. Flowers: Found in crowded, branched clusters at the end of each stem. Fruit and Seeds: Small, shiny brown seeds. FRUIT Photo: Leslie J. Mehrhoff, University of Connecticut, Bugwood.org Photo: Leslie J. Mehrhoff, University of Connecticut, Bugwood.org TREATMENT: Mowing and plowing must be ongoing, or efforts will increase the population. Herbicide application in late summer or fall is the best option. Once the canarygrass is gone, reseeding with native plants is beneficial. For additional information and full treatment option descriptions, visit

13 WHITE AND YELLOW SWEET CLOVER Meliotus alba and officinalis BE ON THE LOOKOUT FOR THIS INVADER! Photo: Steve Dewey, Utah Habitat Preference: Open, dry sites such as roadsides, old field, sand dunes and prairies. Shade intolerant Will tolerate nutrient poor soils. State University, Bugwood.org Height 3-5 ft. tall Description: Herbaceous annual or biennial that can grow up 3 to 5 ft. tall; deep taproot; extensive lateral roots. Seeds may remain viable for 30 years, and germination is stimulated by burning. Tip of the Mitt Watershed Council Funding provided by: Petoskey-Harbor Springs Area Community Foundation

14 LEAVES FLOWERS Photo: Karen A. Rawlins, University of Georgia, Bugwood.org Photo: University of Alaska - Anchorage Archive, Cooperative Extenion Service, Bugwood.org Photo: Jamie Nielsen, University of Alaska Fairbanks, Cooperative Extenion Service, Bugwood.org IDENTIFICATION Leaves: Clover leaves with three finely toothed leaflets. Stems: Upright; many-branched; smooth; often hollow; leafy stems that may be spreading near the base giving the plant a bushy appearance. Flowers: Numerous, white or yellow in color, pea-like, fragrant, crowded onto elongated stems; bloom May through September. Fruit and Seeds: Seed pod, tiny, wrinkled, contains 1-2 small, tough seeds. TREATMENT: Small infestations may also be eradicated by pulling first year plants in the fall, after root-crown buds have developed; pull second year plants before flowering. Flowering plants should be removed and disposed of by burning or placing in a landfill. Fire increases germination-poorly planned prescribed fires will increase infestations. Ideally, plants should be burned in early spring, followed by a late spring burn or herbicide application the following year. For additional information and full treatment option descriptions, visit

15 THREE TYPES OF THISTLE BE ON THE LOOKOUT FOR THESE INVADERS! Photo: Mary Ellen (Mel) Hart, Bugwood.org CANADA THISTLE Cirsium arvense SEE BACK for information on Bull Thistle and European Swamp Thistle Description: Perennial thistle ranging in height from 2-5 ft.; forms large monocultures. Leaves are crinkly with spiny toothed margins. Stems are slender, branching toward the top, and become increasingly hairy with age. Treatment: Monitor sunny, disturbed areas. Begin control efforts in highest quality areas; pull seedlings within 2.5 weeks after germination or they become perennial. Clonal; resprouts from root fragments. Fire NOT effective - it will stimulate this species. Herbicides are most effective with two applications per season: in spring, just before flowering, and in fall on new growth after mowing-treat all stems. May require 5-10 years of ongoing efforts. Tip of the Mitt Watershed Council Funding provided by: Petoskey-Harbor Springs Area Community Foundation

16 EUROPEAN SWAMP THISTLE Cirsium palustre Description: Herbaceous biennial ranging in height from ft. tall. Prefers moist, acidic soil conditions, shade intolerant; found in ditches, wetlands, swamps, fens. Leaves are covered in loose matted hairs and spiny teeth along margins. Spiny lengthwise wings along thick stems. In combina- Photo: Kristian Peters, tion, its small flowers/seed heads and spiny stems Wikimedia Commons distinguish it from other thistles. Treatment: Monitor moist sites including wetlands, forest edges and fields- European swamp thistle blooms in June and July but can be identified by its thorny winged stems and small flower heads throughout the growing season. Mowing or cutting close to the ground throughout the growing season can reduce infestations; flower heads should be burned or placed in a landfill. Foliar herbicide treatment effective; can be used on fall rosettes, when plants are small and during the bud/flowering stage. BULL THISTLE Cirsium vulgare Description: Clumping biennial that forms a thick taproot in its first growing season. Leaves are covered with 'soft' hairs and needle-like spines on the margin. Juvenile phase produce a single rosette with a taproot up to 28 in. long; rosette may grow to 3.3 ft. in diameter. Bull thistle will form an erect branched habit in its second season on which the large purple blossoms will form if left unmowed. Photo: Loke T. Kok, Polytechnic Institute and State University, Bugwood.org Treatment: Least problematic of the invasive thistles. Cutting/Mowing is effective if done before seedhead development. Herbicide can be effective as well. Efforts should be focused early in season. For additional information and full treatment option descriptions, visit

17 WILD PARSNIP Pastinaca sativa BE ON THE LOOKOUT FOR THIS INVADER! Photo: Leslie 5 Habitat Preference: Open spaces such as prairies, savannas and fens Tolerates a range of soil conditions Shade intolerant Reproduces by seed J. Mehrhoff, University ofconnecticut,bugwood.org Height Up to 5 ft. tall Description: Tall, herbaceous biennial, dies after producing seed; up to 5 ft. in height; long, thick taproot. Chemicals found in leaves, stems, and flowers of wild parsnip can cause skin rashes, burns, and blisters, especially in the presence of sunlight. Tip of the Mitt Watershed Council Funding provided by: Petoskey-Harbor Springs Area Community Foundation

18 IDENTIFICATION LEAVES FRUIT FLOWERS Photo: Ohio State Weed Lab Archive, Ohio State University, Bugwood.org Photo: Ohio State Weed Lab Archive, Ohio State University, Bugwood.org Leaves: 6 in. long alternate leaves with 5-15 oval, smooth, toothed leaflets. Stems: Upright; unbranched; thick; hairy; grooved. Flowers: Numerous, small, yellow in color, 5 petals, found in flat groupings (similar in appearance to dill); up to 6 in. wide; bloom June through mid-july. Fruit and Seeds: Seeds are large, flat, round, yellowish; can remain viable for up to four years. Photo: John Cardina, Ohio State University, Bugwood.org TREATMENT: Easiest to identify in June and July when it begins to bloom. Herbicide is effective on the basal rosettes (base leaves), which can be exposed by fire early in the season. The plant can also be cut 2 in. below the soil surface if flowering has begun. Remove flower and seed heads from site. For additional information and full treatment option descriptions, visit

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20 RESOURCES Michigan Natural Features Inventory mnfi.anr.msu.edu Midwest Invasive Species Information Network misin.msu.edu Center for Invasive Species and Ecosystem Health invasive.org Michigan Department of Natural Resources & Michigan Department of Environmental Quality : Terrestrial Invasive Plants, Mammals, and Birds Questions about identification, management and control terrestrial invasive species. Sue Tangora, Wildlife Biologist DNR - Wildlife Division tangoras@michigan.gov Questions about identification and the control of invasive Phragmites. Kevin Walters, Aquatic Biologist DEQ - Water Resources Division waltersk3@michigan.gov Tip of the Mitt Watershed Council Bay Street, Petoskey, MI