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 …

Najas minor, Brittleleaf Naiad


Invasive Species: Najas minor, Brittleleaf Naiad

Brittleleaf naiad is an invasive annual forb that is native to Europe. The highly branched stems can grow up to 4 ft. (1.2 m) in length and fragment easily; hence the common name. …

Myriophyllum heterophyllum, Variable Watermilfoil


Invasive Species: Myriophyllum heterophyllum, Variable Watermilfoil

Variable watermilfoil is an invasive perennial aquatic herb that has leaves of two noticeably different forms. The submerged leaves are finely dissected, whorled, reddish/greenish-brown, and 1/2 to 2 1/2 in. (1.3 to 6.4 …

Securigera varia, Crownvetch


Invasive Species: Securigera varia, Crownvetch

Crownvetch is a low-growing, invasive, herbaceous vine that usually forms thickets up to 3 ft. (0.9 m) in height. The leaves are pinnately compound with 9 to 25 pairs of leaflets and a terminal …

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 …

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 …

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 …