African boxthorn (Lycium ferocissimum)
African boxthorn (Lycium ferocissimum)
African boxthorn (Lycium ferocissimum)

Description
Erect shrub with many rigid branches growing up to 4 meters high and about 3 meters across. The branches are leafy and often end in a spine. The stems are light-brown when immature and brown or grey when mature. The stems branch vigorously. Spines are up to 15 centimeters long, and shoot from the main stems, with smaller spines on the numerous, small branches. Each of these smaller branches ends with a spine. The leaves are glabrous (without hairs...

African rue (Peganum harmala)
African rue (Peganum harmala)
African rue (Peganum harmala)
African rue (Peganum harmala)

Other common names
Wild rue, Rue weed, Syrian rue

Description
African rue is a multi-branched and bushy perennial. A member of the Caltrop family, it is a succulent plant, with bright-green, alternating leaves that are smooth and finely divided with long, narrow segments. Plants grow 1.5 feet tall and three to four feet in diameter. Flowers are white, with five individual petals, and are present in spring to early fall. Fruit is...

Austrian peaweed (Sphaerophysa salsula)
Austrian peaweed (Sphaerophysa salsula)
Austrian peaweed (Sphaerophysa salsula)
Austrian peaweed (Sphaerophysa salsula)

Other common names
Swainsonpea

Description
Perennial, flowers from May to July. A creeping plant with compound leaves. Numerous leaflets are oval and covered in hair. Flowers are 1/4 to 1 inch long and orange-red. Many seeds in bladder-like translucent pods.

Impacts
This plant was introduced from Asia and is commonly found in western states in irrigated fields and moist soil in waste places along...

Barbed goatgrass (Aegilops triuncialis)
Barbed goatgrass (Aegilops triuncialis)
Barbed goatgrass (Aegilops triuncialis)

Description
Annual, grows 8 to 16 inches tall with few to many culms. Leaf sheaths contain white hairs when young, becoming more or less smooth once mature. The blades are rigid, sharp, pointed and spreading. Grain 1/4 inch long, resembling a wheat kernel.

Impacts
Barbed goatgrass is a rangeland and dryland crop invader. This species, aside from dominating dryland pastures in California, readily crosses with wheat, producing sterile...

Bearded creeper (Crupina vulgaris)
Bearded creeper (Crupina vulgaris)
Bearded creeper (Crupina vulgaris)
Bearded creeper (Crupina vulgaris)

Other common names
Common crupina

Description
Winter annual, flowers June to July. Grows one to three feet tall. Leaves alternate, with a coarse, rough texture when touched. Cotyledons (seed leaves) have a dark-purple vein. Flower heads are narrow and topped with pink, lavender or purple flowers in groups of up to five. Seeds have a distinct ring of dark, stiff bristles encircling a broad end.

Impacts...

Biddy-biddy (Acaena novae-zelandiae)
Biddy-biddy (Acaena novae-zelandiae)
Biddy-biddy (Acaena novae-zelandiae)

Other common names
Bidibid, Bidgee-widgee, Piri-piri-bur

Description
Perennial that grows four to eight inches tall. Biddy-biddy spreads by stolons that root at the nodes, and plants form large mats where individual plants are indistinguishable. The plant stems are prostrate to erect depending on conditions. Leaves alternate and are compound, with mature plants having 5 to 11 leaflets, 1/4 to 2/3 inches long. Flower heads are...

Buffalobur (Solanum rostratum)
Buffalobur (Solanum rostratum)
Buffalobur (Solanum rostratum)
Buffalobur (Solanum rostratum)

Other common names
Kansas thistle, Texas thistle, Colorado bur

Description
Annual, flowers midsummer to September. Grows up to two feet high. The stems, leaves, and even flowers sport many sharp spines. Leaves are deeply lobed and grow up to five inches long. Yellow flowers are one inch across with five petals. A dry berry covered with sharp spines contains numerous black, wrinkled and flattened seeds.

Impacts...

Bull thistle (Cirsium vulgare)
Bull thistle (Cirsium vulgare)
Bull thistle (Cirsium vulgare)
Bull thistle (Cirsium vulgare)

Other common names
Common thistle, Spear thistle

Description
Biennial, blooms July to September and grows two to five feet tall. It has many branches sporting green to brown spines and hairs. Leaves are pinnately lobed, hairy, prickly on the upper side and cottony underneath. Flowers are 1 1/2 to 2 inches wide and clustered at ends of branches. Flowers are dark purple. Seeds are topped by a circle of plume-like white hairs.

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Butterfly bush (Buddleja davidii)
Butterfly bush (Buddleja davidii)
Butterfly bush (Buddleja davidii)
Butterfly bush (Buddleja davidii)

Other common names
Summer lilac

Description
Perennial shrub, flowers mid to late summer. Grows up to 10 feet tall. Leaves are narrow, opposite and green to blue-gray. Flower heads are lilac-like but come to a more definite point. Flowers are small and purple.

Impacts
This plant is a pioneering species that dominates open habitats. It poses an ecological threat to dryland meadows, open slopes and dunes...

Camelthorn (Alhagi pseudalhagi)
Camelthorn (Alhagi pseudalhagi)
Camelthorn (Alhagi pseudalhagi)
Camelthorn (Alhagi pseudalhagi)

Other common names
Caspian manna

Description
Perennial, flowers June to July. Grows 1 1/2 to 4 feet tall. Stems are greenish with slender spines 1/4 to 1 3/4 inches long. Leaves are wedge-shaped, hairless on the upper surface, 1/4 to 1 1/4 inches long. Flowers are small, pea-like, and pinkish-purple to maroon; they occur on short, spine-tipped branches along the upper portion of the plant. Reddish-brown, jointed seed pods curve...