What Are Wisconsin Invasive Plants With Thorns?

Wineberry

• Similar in appearance to a red raspberry, wineberry has edible red berries that ripen in the summer. The leaves of this perennial shrub are green on top and white on the underside, due to small, white hair-like growth. They grow on long arching canes, covered with small spines or thorns. Purplish-red hairs, as well as smaller thorns, cover the stems of the leaves and base of the flowers. This shrub is a native of Asia and spreads via wildlife, according to the Wisconsin Department of Natural Resources. Wineberry thrives in full sun and moist soil. To control this invasive plant, cut the canes to the ground and apply herbicide.

Japanese Barberry

• The barberry native to the United States does not grow in Wisconsin. The Japanese barberry, imported from Japan for ornamental use, escaped into the wild via wildlife eating the bright red berries that ripen in the fall, according the Wisconsin Department of Forestry. Because spines cover this compact bush, which typically grows to only about 3 feet tall, it requires careful handling. In spring, yellow flowers bloom along arching stems; the leaves of this species turn crimson in autumn. Japanese barberry reproduces by seed or shallow underground roots. You can dig up and remove this shrub in early spring.

Multiflora Rose

• Although Multiflora rose was once planted to prevent soil erosion, it has since aggressively spread into the grasslands of southern Wisconsin and is considered an invasive species. As with other members of the rose family, sharp thorns cover the Multiflora rose’s canes. This shrub can grow to 15 feet tall and wide, but usually remains around 4 feet tall. The rose blooms in late spring; the flowers are white and small, generally one and one-half inches across. This plant is difficult to control because of the dense growth habit and sharp thorns, as well as its aggressive propagation. Each plant can produce up to 500,000 seeds every year, according to the Wisconsin Department of Natural Resources. The most efficient method of control is to cut the canes to the ground and treat with herbicide.