Lancaster County
Weed Control Authority
Weed Control Authority
lancaster.ne.gov
| Life Span: | Perennial |
|---|---|
| Stems: | 2 to 4 feet tall; hollow; erect; branched above; no leafy wings or spiny margins on upper stems below flowers. |
| Leaves: | Moderate to coarsely lobed, usually wavy with spiny margins. Upper side light to dark green, shiny, hairy to hairless. |
| Inflorescence: | Small 1/2 to 3/4 inch diameter rose purple, sometimes white color, male/female flower on separate plants. |
| Roots: | Extensive vertical and horizontal root system. |
| Life Span: | Biennial or short-lived perennial. Rosette formed during the first year. |
|---|---|
| Stems: | Erect, much branched with rough pubescence. Height 1 to 2-1/2 feet tall. Often 'branched near or directly above the base. |
| Leaves: | Alternate, deeply divided into narrow segments. Short, or no, leaf stalks. Upper leaves nearly entire or minutely lobed. Gray-green color and covered with fine hair. |
| Inflorescence: | Numerous solitary heads clustered at end of branches, approximately 3/4 inch in diameter. White, pink, or lavender disk flowers. Flower heads surrounded by spiny bracts. Flowers July through September. |
| Roots: | Stout, elongated taproot. |
| Life Span: | tall herbaceous perennial. |
|---|---|
| Stems: | Stems are usually square, but may become five-or-six-sided and quite woody as plants mature. May grow up to ten feet tall and four feet wide, producing as many as 50 stems per plant. |
| Leaves: | Leaves may be opposite, alternate or in whorls of three. The leaves are lance shaped and directly attached to stems. Leaves and stems may be smooth or covered with soft hairs. |
| Inflorescence: | The length of the spike inflorescence ranges from one inch to more than three feet long, with up to 3,000 flowers produced on an individual plant. The reddish-purple flowers have five to seven petals. A single mature plant can produce as many as 2.5 million seeds each year. Seeds are very small (1 mm.) and dust like, and are easily carried by wind or water. |
| Roots: | The woody roots form a dense mat underground, up to 20 inches in diameter. |
The Director of Agriculture determines which plants are to be deemed as "noxious" and the control measures to be used in preventing their spread. In Nebraska, the following weeds have been designated as noxious: