Johnsongrass (Sorghum halpense)

Origin: Mediterranean region
Use: Perennial, warm season, introduced grass that provides fair grazing for wildlife; good grazing for livestock.
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Plant Description:
General  Characteristics of Johnsongrass
Life Span  Perennial
Growth Form  erect, rhizomes
Management:
Seeding Rate 
40" Rows:  Broadcast: 


20 to 25 pounds pure live seed per acre
20 to 25 pounds pure live seed per acre
Planting Date  April-May
Planting Depth 0.25 to 0.75 inch
pH requirement 5.0 to 7.5
Rainfall requirement 32 to 60 inches
Soil texture  Sandy: 
Loam: 
Clay: 

High
High
High
Cold Tolerance: High
General  Provides fair grazing for wildlife; good grazing for livestock
ID Features:
Habit: 		Perennial from extensive thick creeping scaly rhizomes, or annual by winter killing.
Culms: 		50-150 cm. tall, simple or branched.
Blades: 	20-70 cm. long, 5-30 mm. wide, flat, somewhat narrowed towards the rounded base,
		drooping, margins mostly rough.
Sheaths: 	Usually shorter than the internodes.
Ligule: 	Membranous, ciliate, 2-3 mm. long.
Inflorescence: 	Panicle open, large 15-50 cm. long, oblong to oval, finally exserted,
		branches verticillate, axils pubescent to villous, the short branchlets with
		short peduncled racemes, each with 1-few racemes, of a few joints, the spikelets
		in pairs (or at the ends of the branchlets in three) at each node, one sessile and
		perfect, awned, the other(s) pedicellate, awnless, usually staminate.
Spikelets: 	Sessile spikelet 4.5-5.5 mm. long, ovate-lanceolate, pale green or yellowish to
		purplish; pedicellate spikelets 5-7 mm. long, lanceolate, narrower than the
		sessile one, glabrous to sparingly pubescent, acuminate, usually staminate.
Glumes: 	As long as the spikelet, sparsely or densely pubescent with appressed
		silky hairs, several nerved, the first broad, flattened dorsally, 3-toothed at
		the obtuse apex, the margins inrolled, the second not so broad, somewhat keeled.
Sterile lemma: 	Slightly shorter than the glumes, hyaline.
Lemmas: 	Hyaline, about half as long as the spikelet, broadly oval, 2-lobed, pubescent,
		bearing a readily deciduous awn 8-15 mm. long, spiral below, much exserted,
		more or less bent.  Lemma and palea of pedicellate spikelet shorter and narrower, hyaline.
Habitat: 	Open ground, fields and waste places.  July-October.
Use: 		Troublesome because of difficulty of eradication on account of the strong rhizomes.
		In northern Kansas most winters kill the roots.
Remarks: 	Under certain conditions the leaves produce dhurrin, a cyanogenetic glucoside
		which may bring about hydrocyanic poisoning in grazing animals.
		The leaves are often splotched with purple, due to a bacterial disease.
Special Notes:
  • May cause nitrate poisoning, prussic acid poisoning, interstital cystitis like other sorghums.
  • Does not tolerate close continuous grazing

    Johnsongrass (Sorghum halpense) Information #1