Orange hawkweed (Hieracium aurantiacum)
Orange hawkweed (Hieracium aurantiacum)
Orange hawkweed (Hieracium aurantiacum)
Orange hawkweed (Hieracium aurantiacum)

Other common names
Devil's paintbrush

Description
Perennial with above-ground runners (stolons) that root at the tips. Roots are shallow and fibrous. The plant grows up to 12 inches tall and contains milky juice. The vibrant orange-red flowers are clustered at the top of a leafless stem. Stiff, black, glandular hairs cover flower stalks. Leaves are hairy, lance-shaped, up to five inches long, and exclusively basal.

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Ovate goatgrass (Aegilops ovata)
Ovate goatgrass (Aegilops ovata)
Ovate goatgrass (Aegilops ovata)

Description
Winter annual, flowers May to July. Grows 10 inches tall. Similar to Barbed and Jointed goatgrass, except spikes are ovate-cylindric, and they disperse as units at maturity and do not break apart into joints.

Impacts
Goatgrasses are rangeland and dryland crop invaders. This species, aside from invading dryland pastures in California, readily crosses with wheat-producing sterile seed and unmarketable wheat.

Parrot feather (Myriophyllum aquaticum)
Parrot feather (Myriophyllum aquaticum)
Parrot feather (Myriophyllum aquaticum)
Parrot feather (Myriophyllum aquaticum)

Other common names
Brazilian water milfoil

Description
An attractive aquatic plant with feathery lime-green leaves arranged in whorls on long stems (rhizomes). Flowers are small and white. The submersed leaves are limp and often appear to be decaying, but the stems are very robust. The surface parts of the plants are the most distinctive trait, as they can grow up to a foot above the water and look almost like small fir trees. Parrot...

Paterson's curse (Echium plantagineum)
Paterson's curse (Echium plantagineum)
Paterson's curse (Echium plantagineum)
Paterson's curse (Echium plantagineum)

Other common names
Salvation Jane, Riverina bluebell

Description
An erect annual or biennial member of the borage family, generally 1 to 3 feet tall. Plants are often multi-branched with an abundance of stout hairs on stems and leaves. Reproduction and spread is by seed. Stems are erect, light-green, bristly, stout, and branching mainly toward the top. Leaves are green to light-green, alternate, hairy and thick. Flowers are...

Perennial peavine (Lathyrus latifolius)
Perennial peavine (Lathyrus latifolius)
Perennial peavine (Lathyrus latifolius)
Perennial peavine (Lathyrus latifolius)

Other common names
Everlasting peavine, Everlasting-pea, Perennial pea, Perennial sweetpea

Description
A widely established European native identified in every state except Florida and North Dakota. Annual growth emerges from perennial roots each spring, growing to a length of 2 to 7 feet. Stems are broadly winged with long, well-developed tendrils. Pea-like flowers are one inch long and can be white, red or pink. Leaflets are well-...

Perennial pepperweed (Lepidium latifolium)
Perennial pepperweed (Lepidium latifolium)
Perennial pepperweed (Lepidium latifolium)
Perennial pepperweed (Lepidium latifolium)

Other common names
Tall white top

Description
Perennial, blooms May to September. Grows 1 to 6 feet tall. Basal leaves are larger than upper leaves, lanceolate, and bright-green to gray-green. Flowers are white, very small, and form dense clusters near the ends of branches. Flowers produce a distinctive odor. Seed are very small, flattened, slightly hairy and reddish brown.

Impacts
Perennial...

Plumeless thistle (Carduus acanthoides)
Plumeless thistle (Carduus acanthoides)
Plumeless thistle (Carduus acanthoides)
Plumeless thistle (Carduus acanthoides)

Description
Winter annual or biennial herb, flowers May to July. Grows 1 to 4 feet tall. Stems are covered with spiny wings. Rosette leaves are 4 to 8 inches long; stem leaves alternate and blend into the stem. Flower heads are in clusters of 2 to 5 and are usually purple, but can be yellow or white.

Impacts
Each plant generates thousands of seeds. It is very aggresive, limiting grazing and other livestock management, threatening...

Poison hemlock (Conium maculatum)
Poison hemlock (Conium maculatum)
Poison hemlock (Conium maculatum)
Poison hemlock (Conium maculatum)

Description
Biennial, blooms in early summer. Grows 3 to 7 feet tall. Stems are erect. Leaves alternate, one per node, and are petioled and pinnately divided. Flowers are white in compound stemmed umbels, mostly flat on top. The enlarged taproot is the most easily recognizable feature.

Impacts
Grows in pastures, streams and irrigation ditches. Several deaths of livestock and humans are attributed each year to this species.

Policeman's helmet (Impatiens glandulifera)
Policeman's helmet (Impatiens glandulifera)
Policeman's helmet (Impatiens glandulifera)
Policeman's helmet (Impatiens glandulifera)

Other common names
Ornamental jewelhead, Jewelhead, Himalayan balsam

Description
An herbaceous annual that is succulent, smooth-stemmed and hairless. The plants can reach 10 feet tall. The upright, hollow stems are easily broken and have a purple tinge. The leaf arrangement can be opposite or whorled, with three leaves per node. Leaf shape varies from oblong to egg-shaped, with serrated edges. The flowers of this plant are solitary,...

Pom pom weed (Campuloclinium macrocephalum)
Pom pom weed (Campuloclinium macrocephalum)

Description
Erect perennial herb with fluffy pink flowerheads. Stems are green to purplish, up to 1.3 meters high, dying back annually to a root crown. Leaves are light-green and scattered along the length of the stem, but clustered at the base to form a rosette up to 80 millimeters long and 20 millimeters wide, with serrated margins. Light purple to pink compact flower heads that are situated terminally, blooming December to March. Produces fluffy seeds that are...