Plants perennial; rhizomatous. Culms 50-200 cm tall, 0.4-2 cm thick; nodes appressed pubescent; internodes glabrous. Ligules2-6 mm, membranous, conspicuously ciliate; blades 10-90 cm long, 8-40 mm wide. Panicles 10-50 cm long, 5-25 cm wide, primary branches compound, terminating in rames of 1-5 spikelet pairs; disarticulation usually beneath the sessile spikelets, sometimes also beneath the pedicellate spikelets. Sessile spikelets bisexual, 3.8-6.5 mm long, 1.5-2.3 mm wide; calluses blunt; glumesindurate, shiny, appressed pubescent; upper lemmas unawned, or with a geniculate, twisted awn to 13 mm; anthers 1.9-2.7 mm. Pedicels 1.8-3.3 mm. Pedicellate spikelets staminate, 3.6-5.6 mm; glumes membranous to coriaceous, unawned. Caryopses not exposed at maturity. 2n = 20, 40; several dysploid counts also reported.

Sorghum halepense is native to the Mediterranean region. It is sometimes grown for forage in North America, but it is considered a serious weed in warmer parts of the United States. It hybridizes readily with S. bicolor, and derivatives of such hybrids are widespread. The annual Sorghum almum Parodi, which has wider (2-2.8 mm) sessile spikelets with more veins in the lower glumes (13-15 versus 10-13) than S. halepense, is one such derivative.

Similar species: Sorghum bicolor is an annual or short-lived perennial that lacks rhizomes and often has exposed mature caryopses.

Flowering: early July to late September

Habitat and ecology: Introduced from the Mediterranean, this species grows near grain elevators and in sandy road shoulders after a recent seeding (likely being in the seed mix). This species is a problem weed in the south, but is most likely not cold hardy here.

Occurence in the Chicago region: non-native

Etymology: Sorghum comes from the plant's Italian name, sorgo. Halepense means "from Aleppo, Syria."

Author: The Morton Arboretum