An Illustrated Guide to ARIZONA WEEDS
The University of Arizona Press
HENBIT-Lamium amplexicaule L.
DESCRIPTION-A low slender annual, winter annual, biennial, or rarely a short- lived perennial, reproducing by seeds, by stems rooting at the lower joints, and sometimes by slender rhizomes. The weak 4-angled stems, 4 to 16 inches high, branching from the base, are erect at first but soon spreading, the lower part often reclining on the ground and rooting at some joints. The leaves are opposite, usually less than 1 inch long, hairy, and round-toothed or lobed. They are widely spaced except at the tops of the stems, often 3 to 6 inches apart. The lower ones are heartshaped on slender stalks; the upper ones much broader, stalkless and clasping the stem. The slender pink or purple flowers, 1/3 to 2/3 inch long, are tubular with 2 lips, the upper hairy on the back, and the lower spotted. The stalkless flowers are borne in the axils of the upper leaves, 6 to 10 or more forming a circle around the stem. The calyx, yellow hairy with 5 sharp bristlelike teeth, remains on the plant and encloses the 4-lobed fruit. The calyx separates into 4 seedlike nutlets, commonly referred to as seeds. They are 3-angled, 1/16 to more than 1/12 inch long, grayish brown, and sprinkled with silverish bumps.
DISTRIBUTION-Henbit is an introduced European weed, growing in moist often shady soil, but also in the sun. In Arizona it is primarily a pest in lawns, especially new lawns, also found in gardens, flowerbeds, plowed fields, and waste places. Troublesome mostly in the spring, and sometimes again in the fall at the lower elevations. Widespread throughout the southern and central part of the state and locally abundant in many areas, it is scattered in the northern part; 100 to 9,000 feet elevation; flowering February to November.
Copyright (c) 1972 The Arizona Board of Regents