Aegopodium podagraria, Bishops Goutweed


Invasive Species: Aegopodium podagraria, Bishops Goutweed

Bishops goutweed is an invasive creeping perennial that can grow to 3 ft. (1 m) tall. The compound leaves are alternate and have sheathing bases. The leaves at the top of the stem are smaller and have fewer leaflets. The leaflets are dentate and 1 to 3 in. (2.5 to 7.6 cm) long. Blooming occurs in June, when a flat, 2 to 4 in. (5 to 10 cm) wide cluster of small white …

Acroptilon repens, Russian Knapweed


Invasive Species: Acroptilon repens, Russian Knapweed

Russian knapweed is an invasive¬†perennial forb that can grow to 3 ft. (1 m) in height. Stems originate from a basal rosette of leaves. The rosette leaves can be unlobed to very lobed and are 2 to 4 in. (5 to 10 cm) long. Stem leaves are oblong, pinnately lobed to entire, and up to 6 in. (15.2 cm) in length at the base of the stem; they become smaller and less …

Centaurea calcitrapa, Purple Starthistle


Invasive Species: Centaurea calcitrapa, Purple Starthistle

Purple starthistle is a biennial to perennial invasive plant. It grows 2 to 3 ft. (0.6 to 0.9 m) tall. The stems and leaves are covered with fine hairs. Lower and basal leaves are divided or deeply lobed. Leaves become less divided toward the apex of the plant. Flowering occurs from July to October, when purple to pink blooms develop at the ends of the stems. Floral bracts are tipped with 1 in. …

Carduus tenuiflorus, Slenderflower Thistle


Invasive Species: Carduus tenuiflorus, Slenderflower Thistle

Slenderflower thistle is an herbaceous winter annual or biennial plant that invades disturbed areas. The most serious infestations occur in the Pacific coastal states, but slenderflower thistle also occurs sporadically in the eastern United States. Plants grow up to 6 ft. (1.8 m) tall with single or multiple spiny stems with wings arising from the base of the spines. Stem wings can be up to 0.4 in. (10 mm) wide. Leaves are deeply …

Solanum dulcamara, Bittersweet Nightshade


Invasive Species: Solanum dulcamara, Bittersweet Nightshade

Bittersweet nightshade is an invasive¬†perennial plant native to Eurasia. Plants can reach up to 6.6 ft. (2 m) tall, either erect or clambering. Leaves are petiolate, alternate, three-lobed (upper part of the stem), acuminate, and up to 3.1 in. (8 cm) long. Flowering occurs in May to November when purple flowers develop. Petals are recurved and up to 0.4 in. (9 mm) long. Stamens (5) are bright yellow and fused together around …

Vinca major, Bigleaf Periwinkle


Invasive Species: Vinca major, Bigleaf Periwinkle

Bigleaf periwinkle is an invasive evergreen to semi-evergreen trailing vine that reaches to over 6.6 ft. (2 m) in length. The stems are stout, somewhat woody, and green. The opposite, glossy leaves are 1.5 to 2.5 in. (3.8 to 6.4 cm) long and heart-shaped to elliptical. Some varieties have variegated leaf colors. Flowers are violet to blue (possibly white), 1.5 to 2 in. (3.8 to 5.1 cm) wide, and five-petaled. Bigleaf periwinkle invades …