Weeds are a group of invasive plants with the ability to choke or kill other plants by taking over their habitat. Common characteristics of weeds include rosette basal leaves and a rapidly growing, spreading formation. Some weeds produce colorful flowers that gardeners plant as biennials, perennials or summer and winter annuals. Ranchers often use weeds as forage plants for livestock; however, some weeds are toxic to animals. Many species of weeds develop tall red stems.
Devil's beggarticks (Bidens frondosa) is a 42-inch tall annual summer weed native to North America. This Asteraceae family member forms from lengthy reddish square stems. A fall flowering weed, devil’s beggarticks produces small yellow blooms with spine-covered seeds. Common water hemp (Amaranthus rudis) is an upright annual weed that grows during the warm summer season. This invasive plant grows up to 8 feet in height with smooth branching red stems and has sword-shaped leaves with notched tips. Common water hemp has tiny green flowers that form along the plant's branches.
Annual kochia (Kochia scoparia) is an invasive quick-growing shrub indigenous to Europe and Asia with green stems that mature to red with age. This Chenopodiaceae plant family member reproduces by seeds dispersed by the wind. Annual kochia is 1- to 7-foot tall forage grown in dry climates like grasslands, deserts and prairies. Italian ryegrass (Lolium multiflorum) is a 3-foot tall winter annual weed with leaf sheaths that develop on red stems. The red stems of this Poaceae family member helps identify it as the annual variety of ryegrass since the perennial species does not have red stems. A European native, Italian ryegrass is an established plant grown throughout regions across the U.S.
Filarees (Erosdiium spp) are broadleaf biennial weeds also grown as winter annuals. This Geraniaceae family plant ranges in height from 2 to 3 feet with a low-spreading configuration. Filaree plants come in a red stem variety with fully divided rosette leaflets. Carolina geranium (Geranium carolinianum) is a biennial weed with upright forming pink to red colored stems that grow to 28 inches in height. This spring flowering plant produces distinctive white-pink to purple blossoms. A member of the Geraniaceae family, Carolina geranium has basal rosette leaves with serrated edges.
Common pokeweed (Phytolacca Americana) is a large herbaceous weed with a shrub-like formation native to eastern areas of the U.S.. This invasive perennial grows up to 10-feet tall with huge taproots and long reddish-purple stems. During the fall, common pokeweed bears purple berries that resemble grapes. Tall ironweed (Veronica altissima) is an erect perennial weed endemic to meadows and pastures in the U.S. A member of the Compositae plant family, this tall weed grows to 7 feet in height. The deep red stems of the tall ironweed branch off at the top of the plant and develop purple saucer-like flowers.
- Virginia Tech Extension: Devil’s Beggarticks or Stick-tights—Bidens Frondosa
- Purdue University Extension; Kochia; D.J. Undersander, et al.
- Virginia Tech Extension: Annual or Italian Ryegrass
- North Carolina State University Extension; Weed Identification in Pastures and Hayfields; July 2009
- University of California at Davis Extension: Filarees