Invasive Plants in the Midwest www.mipn.org
Oriental Bittersweet - Celastrus orbiculatus Perennial, woody, climbing vine, flowers from May to June, fruits in fall Leaves alternate, dark green, serrated Fruits, greenish-yellow to dull-yellow when ripe, produced along the branches Vine, leaves and fruit covered by seed coat Seeds are surrounded by a bright red fleshy coating, which splits open to expose the seed Threatens most upland community types and well-drained floodplain and riparian corridors, grows in open and shaded areas Flower Flowers along branch Mature Leaf Yellow Seed Coat and Red Fruit (close-up) MIPN.org
Native vs. Non-native Orange Fruits Yellow Fruits American Bittersweet Image - http://www.glsc.usgs.gov/_files/factsheets/2007-2%20identifying%20bittersweet.pdf
How do I Identify the Invasive Bittersweet from the Native Bittersweet without flowers or fruit? If leaves are unfolding you have the invasive C. orbiculatus If leaves are unrolling you have the native C. scandens Collaborators: Noel B. Pavlovic, Stacey Leicht Young, Ralph Grundel, and Krystalynn J. Frohnapple
Black Swallow-wort - Cynanchum louiseae Pale Swallow-wort - Cynanchum rossicum D. Eagan Univ. WI-Madison Black Swallow-wort Vine Herbaceous, perennial vines twine 3-8 feet high. Leaves dark green, shiny, opposite, toothless, narrowly to broadly oval-shaped with pointed tips. Black Swallow-wort flowers tiny, dark purple with 5, pointed, downy (hairy), triangular petals that are as long as wide. Pale Swallow-wort flowers maroon to pink with 5, pointed, hairless, triangular petals that are twice as long as wide. Seed pods milkweed-like, slender and tapered. Seed on silky filaments, wind dispersed. Pale Swallow-wort Seed FLOWERS Black Swallow-wort Pale Swallow-wort Larissa L.Smith Cornell Univ. D. Eagan Univ. WI-Madison Black Swallow-wort Seed Pod D. Eagan Univ. WI- Madison Antonio DiTommaso Cornell Univ. MIPN.org
Threatens most upland community types including woodlands, forests, grasslands, and savannas; can persist in sun or shade D. Eagan Univ. WI-Madison D. Eagan Univ. WI-Madison
Leaves and vine Chinese Yam or Air potato - Dioscorea oppositifolia Perennial, high climbing vine; blooms in summer and produces small potato-like tubers in fall Leaves deeply lobed (shield-shaped) J. Shimp IL DNR Leaves along established vine Type 2 Leaf Flowers small and white (green to yellow) with cinnamon fragrance Threatens floodplain and upland forests, riparian corridors, savannas, drainage ways; grows in full sun to full shade J. Shimp IL DNR Bulbil Newly emerged plant Type 1 Leaf Yam invasion J. Shimp IL DNR Bubil with dime for size reference MIPN.org
Chinese yam invasion in southern Illinois. Photo taken in early spring before vines began to climb.
Native vs. Non-Native Dioscorea oppositifolia Dioscorea villosa
MIPN.org Japanese Hops - Humulus japonicus Annual, herbaceous, twining vine, flowers July-September. Stem very rough, with downward pointing prickles, climbs up to 7.5 feet. Flowers, greenish, produced on a spike and are inconspicuous. Fruit a green hops. Stem barbs Threatens open woodlands, fields, prairies, riparian corridors. D. Eagan, Univ. WI-Madison Vine with pencil for size reference D. Eagan, Univ. WI-Madison Male flowers D. Eagan, Univ. WI-Madison Female flowers
Japanese Hops in Missouri at the confluence of the Mississippi and Missouri Rivers, 2006 Non-Native vs. Native Japanese Hops Native Hops
Mile-a-Minute Weed - Polygonum perfoliatum Herbaceous, annual, trailing vine Leaves are shaped like an equilateral triangle and alternate. M. Jordan, TNC Grows rapidly, scrambling over shrubs and other vegetation, threatens woodland edges, wetlands, and riparian corridors. Fruiting vine M. Jordan, TNC Leaves on vine MIPN.org
Kudzu - Pueraria lobata J. Shimp IL DNR Flowers on the vine Perennial, fast growing, semi-woody, vine. Stem twines 30 feet - 90 feet. Flowers purple, pea-like, with a strong grape fragrance, growing from leaf axils in long hanging clusters. Threatens forest edges, old-fields, and also grows in disturbed areas. J. Shimp IL DNR Flower close-up J. Shimp IL DNR Leaves MIPN.org
Japanese knotweed- Polygonum cuspidatum Leaves on a branch Perennial herb, but develops shrub-like form, spreads primarily by vegetative reproduction. Stem, branching, grows 3 ft - 9 ft tall Flowers white-pink, densely crowded on erect or drooping stalks. Threatens riparian corridors, fens, springs and transportation corridors; grows in full shade to full sun. Riparian invasion in South wales Whole plant Flowers MIPN.org
Flowering Rush Butomus umbellatus Perennial, emergent aquatic herb; in shallow water, grows 1-4 feet tall. Emergent leaves grow from base of stem, 2-4 feet tall, stiff and narrow, stem and leaves triangular in cross-section. Submersed leaves are limp. Flowers white or pink in a distinctive flattopped spray. Blooms mid-summer thru early fall. Plants only produce flowers in very shallow water or on dry sites. B. Smith - WDNR Rarely produces seeds; spreads locally by rhizomes and root pieces that break off and form new plants. Threatens marshes, backwaters and shorelines; prefers shallow or slow moving water. Harri Arkkio E. Judziewicz Univ. WI-Stevens Point MIPN.org
NATIVE LOOK-ALIKES: Bur reeds, Sparganium spp. (right); leaves keeled (V-shaped), female flower parts resemble small, spiked balls. V-shaped stem of Bur reed Triangular Flowering rush stem Bur Reed http://www.npwrc.usgs.gov/resource/plants/florane/species/4/spareury.htm
Hydrilla, Hydrilla verticillata Aquatic, herbaceous, submersed, perennial rooted in saturated soil, can grow in water a few inches deep to 20 feet deep. Stem submersed, slender and branching profusely across the water surface. Nancy Tresser, WI. Leaves green, 0.6 inches long, pointed tips, arranged in whorls of 3 to 10 joined directly to stem; whorls in long increments, 1/8 to 2 inches apart. Leaf edges distinctly saw-toothed; plant noticeably rough when pulled through the hand. Reproduces vegetatively, mainly by regrowth of stem fragments, but also by buds at leaf nodes (turions, dark green, 1/4 inch round) and from 1/2 inch x 1/2 inch potato-like tubers (roots) below ground. Tim Murphy, University of Georgia Threatens any freshwater aquatic communities including: springs, lakes, marshes, ditches, streams and rivers. MIPN.org
Brazilian Elodea, Egeria densa Aquatic submersed, perennial herb, very bushy, generally rooted in depths up to 20 feet or drifting; lacks rhizomes or tubers. Stem single or branched; grows to water surface forming dense mats (profuse branching). Leaves bright green, 0.8-1.2 inches long, up to ¼ inch broad, usually in whorls of 4 to 6 (8) in short intervals along stem, leaf edges minutely toothed. Toni Pennington, Portland State University Reproduction from vegetative growth; specialized areas along stem (double nodes, every 6-12 whorls) produce new plants if fragmented from stem. Seeds and female flowers have never been reported from populations in the US. Threatens still and flowing freshwater aquatic communities Bill Haller, University of Florida/IFAS Center for Aquatic and Invasive Plants MIPN.org
LOOK-ALIKES: Brazilian Waterweed; leaves longer, in whorls of 4-6 (8), bushier in appearance, without tubers. Hydrilla; leaves in whorls of 3-8 with tiny spines along the leaf margins. The midrib of each leaf is often reddish. Hydrilla produces tubers (small potato-like structures). Common Waterweed, Elodea canadensis; leaves occur in whorls of 3 around the stem (or opposite), without tubers. Common Waterweed University of Florida Center for Aquatic and Invasive Plants http://plants.ifas.ufl.edu/seagrant/hydcom22.jpg
Giant Manna Grass- Glyceria maxima Perennial, rhizomatous grass grows from 1.6-8.2 feet tall. Stem unbranched Leaves flat, 7 or more on stem, 8.6-11.4 inches long and 0.3-0.8 inches wide, shallowly grooved with prominent midribs. Leaf sheath closed for most of length. Flowering portion of plant (inflorescence) open with many branches (panicle), branches with short, stiff hairs. Inflorescence strongly drooping at maturity with 50 + flattened (laterally compressed) spikelets, MIPN.org
Inflorescence strongly drooping at maturity Stem unbranched, leaves flat, more than 7 on the stem Stem base and roots
MIPN.org Japanese Stilt Grass - Microstegium vimineum Annual grass, flowers and seeds in late September - October. Plants tend to grow 1.5 to 3 in a branching, mat-forming manner Leaves pale green, resembles bamboo Flower spiklets delicate and paired; one spiklet not on a stalk (sessile), one on a stalk (pedicile) Threatens forested wetlands, floodplain forest, moist woodlands, riparian corridors and also grows in disturbed areas Leslie Mehrhoff, IPANE Branching plant K. Kearns WI DNR Leaf with silver-haired mid vein J. Shimp IL DNR Leaves
Non-Native vs. Native M. vimineum has silvery stripe down the midrib (reflective hairs), paired spikelets, slight purplish tinge in fall L. virginica does not have a hairy midrib, single spikelets, no purple tinge Kelly Kearns, WI DNR Kitty Kohot M. vimineum Leersia virginica
Giant Hogweed - Heracleum mantegazzianum Perennial and herbaceous. Stem grows 6 feet - 15 feet tall and is reddish-purple blotched. Leaves large, to 5 feet wide, once compound. Flowers, white, clustered atop 50-150 stalks. Threatens riparian corridors, fens, seeps, moist savannas, and wet prairies, found on roadsides, grows in sunny moist environments. Caution! Do not handle this species with bare hands or skin, the sap can cause severe blistering when exposed to sunlight. D. Eagan, Univ. WI -Madison Purple blotching and hairs on stem W. Vanderplouge FPDCC IL Leaf with pocket knife for size reference MIPN.org
Native vs. Non-native W.Vanderplouge, FPDCC, IL Giant Hogweed leaf D. Eagan, Univ. WI-Madison Glade Mallow leaf D. Eagan, Univ. WI-Madison Glade Mallow American Cow Parsnip (Heracleum lanatum) is shorter (3 to 7 feet) leaves less lobed and non-mottled flower stems D. Eagan, Univ. WI-Madison Great angelica (Angelica atropurpurea) also is much smaller, with pinnately compound leaves, purplish stems and a spherical flowering umbel. http://dnr.wi.gov/invasives/fact/hogweed.htm