invasive

Showing 25–36 of 42 results

Malva neglecta / cheeseweed
- leaves look like grocery store geraniums (Pelargonium)
- flowers are small, pink-ish and often buried in the foliage
- fruits are small (ca. 1/2 in) and round
Melilotus spp / sweetclover
- yellow or white, floppy, tubular flowers in long-ish clusters (racemes)
- 3 small, pointy leaflets with petioles
- rangy, unkempt branching
- roadsides, waste places and sometimes in fields, grasslands
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
Potentilla recta / sulfur cinquefoil
- perennial
- 8 to 30 stems per plant, each with 1-60 flowers
- petals are light yellow; centers are darker, sulfur yellow
- shiny, erect hairs arise at right angles to the stems.
- leaves are alternate and palmately compound, 5-9 leaflets per leaf
- invades both disturbed and undisturbed habitats
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