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 …

Schefflera actinophylla, Octopus Tree


Invasive Species: Schefflera actinophylla, Octopus Tree

Octopus tree is invasive and can grow to 40 ft. (12.2 m) tall. Stems can be single or multi-stemmed. Leaves are palm-like with 7 to 16 leaflets. Leaflets are ovate, entire, and 12 in. (30 cm) long. Flowering occurs in summer to early fall, when large red inflorescences develop at the stem tips. Flowers are red and 1 in. (92.5 cm) wide. Fruits are round, dark purple, and 1/4 in. (7 mm) in …

Populus alba, White Poplar


Invasive Species: Populus alba, White Poplar

White poplar is an invasive tree that can grow 40 to 80 ft. (12.2 to 24.4 m) tall and 40 to 50 ft. (12.2 to 15.2 m) wide. The bark on young trees is smooth and greenish white, becoming gray and wrinkled as trees age. The leaves resemble maple leaves, but the topside of leaves is shiny, dark green while the underside is bright white and hairy. Leaves are 2 to 4 in. …

Phellodendron amurense, Amur Corktree


Invasive Species: Phellodendron amurense, Amur Corktree

Amur corktree is an invasive perennial tree that can grow from 35 to 45 ft. (10 to 14 m) tall. The tree has a short trunk with spreading branches. The bark is thick and corky. Leaves are opposite, compound (divided into 5 to 11 leaflets), and 10 to 15 in. (25 to 38 cm) long. Leaflets are elliptical, acute at the apex, 2.5 to 4.5 in. (6 to 11 cm) long, and smell …

Morus alba, White Mulberry


Invasive Species: Morus alba, White Mulberry

White mulberry is a small, 30 to 50 ft. (9.1 to 15.2 m) tall, deciduous tree that invades disturbed areas throughout the United States. The alternate leaves are polymorphic (variably shaped), 2 to 8 in. (5.1 to 20.3 cm) long, and shiny with blunt teeth and heart-shaped bases. Young bark, the bark along the roots, and the inner bark along the trunk are often bright orange. Older bark is gray with narrow, irregular …