Grasses - Johnsongrass - Forages of Florida - Solutions for Your Life - UF Institute of Food and Agricultural Sciences

Johnsongrass
Species:	Johnsongrass
Scientific Name:	Sorghum halepense
Cultivars:
Growth Habit:	3-6 feet tall, bunchgrass, ligule membranous and at maturity develops a fringe of hairs. Flower: in pairs (lower end) and in threes (upper end). Fertile spikelets are purplish black when mature. Mature inflorescence drops with age. Seeds are 1/8 inch to 3/16 inch long, glossy, mahogany color. Tip of the seed stalk is knob- shaped, different from sudangrass. Roots: fibrous and extensive. Rhizomes: creeping, thick whitish with purple or red, and segmented.
Life Cycle:	Perennial in Florida; flowers year round. Days from emergence to bloom: ~ 45 (if from seedling), and 20-25 (if from rhizomes) From visible flower to seed maturity takes 10 days. Most seed will be shed 4 weeks after flowering. Seedlings develop rhizomes 3 to 4 weeks after emergence (agressively rhizomatous). Seeds can survive lower temperatures than rhizomes. A single plant can produce more than 5,000 nodes in a growing season.
Origin:	Mediterranean region
Production Season:	May to September
Nutritive Value:	Varies with management. Medium to low protein, and medium to low digestibility
Use:	Grazing, hay
Herbarium Image:	For an herbarium image click this link.
Adaptation
Soil:	Sandy-loam, clay loam
pH:	5.0-7.5
Rainfall:	28-60 inches
Temperature:	Grows during warm-season.
Management
Planting Date:	April
Planting Depth:	< 1/4 - 3/4 inch
Seeding Rate:	20 to 25 lb /acre
Seed Cost:	$1.4/lb; $28 to 35/acre
Fertilization:	For fertilization info click this link
Production:	5000 to 7000 lb/acre 300 lb seed/acre is considered good
Notes
For hay, cut at boot stage before the seed matures Does not tolerate close continuous grazing or mowing. Rhizome production is reduced if plants are kept shorter than 12 to 15 inches. Potential nitrate and prussic acid toxicity. If a weed in a pasture, cultural control methods in established stands of Johnsongrass are effective only if rhizome development is controlled.

Johnsongrass

Adaptation

Management

Notes