invasive

Showing 25–36 of 39 results

  • Mentha canadensis / American cornmint

    • crushed leaves smell like peppermint
    • clusters of teeny white-blue-pink flowers in the axils of stem leaves
    • square stems, lance-shaped leaves
    • shaded, moist areas
    • may form large clones

  • Nasturtium officinale / watercress

    • emergent aquatic in slow-ish flowing steams
    • four petaled white flowers in clusters
    • thick, shiny leaves
    • often in dense colonies

  • Phalaris arundinacea / reed canarygrass

    • large, coarse, erect grass
    • long, flat blades with pointy tips...  from base
    • distinct ligule—membranous and long
    • large but compact inflorescences (panicles)
    • often in dense monocultures, e.g. on river banks

  • Plantago major / broadleaf plantain

  • Polygonum aviculare / prostrate knotweed

    • long, prostrate stems around a central point
    • copious red-edged white flowers
    • small green leaves
    • along roadsides, parking lots and wherever trampling occurs
    • an ugly weed you'll see on most of your walks around town

  • Pteridium aquilinum / common bracken

    • a fern with large, triangular fronds, up to 4 ft tall
    • fronds subdivided into triangular leaflets
    • herbaceous perennial
    • deciduous with annual regrowth first appearing as fiddleheads in spring
    • wide range of habitats, including full sun

  • Rhamphospermum arvense / Charlock

    • yellow-flowered brassica; flowers larger than most mustards
    • large-ish leaves with toothed margins
    • erect stems; look for a reddish purple ring at stem junctions
    • disturbed areas, road sides and waste places; prefers high nutrients
    • 1" siliques point out or up, but not down

  • Rumex crispus / curly dock

    • rather large, lance-shaped leaves
    • curly leaf margins, like crisped bacon or "crinkly-wavy"
    • tall flowering stalks with many, many small yellow/green-ish flowers
    • fruits are just like the flowers but deep red
    • widespread and very much a weed

  • Sisymbrium altissimum / tumble mustard

    • inflorescence a raceme with yellow, teeny flowers
    • long, thin seed pods (siliques)
    • blooms throughout the spring and summer
    • shoots look like a bunch of sticks glued together
    • dries and breaks off, then tumbles

  • Solidago canadensis / goldenrod

    • large sprays of yellow flowers in late summer and fall
    • often tall and in large colonies
    • lance-shaped, toothed leaves
    • mostly (but not always) in disturbed areas

  • Taraxacum officinale / dandelion

    • rosette growth habit with lobed leaves
    • yellow dandelion-like flowers - composites with only ray florets
    • only one flower head per stem
    • characteristic puff-ball seedheads
    • found anywhere and anytime

  • Thlaspi arvense / field pennycress

    • inflorescence a raceme with white, teeny flowers
    • oval seed pods ca. 1/3" across
    • blooms late spring and summer
    • continues blooming as pods fill from older flowers
    • common weed in disturbed habitats including cultivated land

Showing 25–36 of 39 results