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Sorghum halepense

Common Name(s):

Phonetic Spelling
SOR-gum ha-le-PEN-see
This plant has low severity poison characteristics.
See below
This plant is an invasive species in North Carolina
Description

Johnsongrass is an erect, 2½ to 7-foot tall, coarse, herbaceous perennial grass in the Poaceae family thought to be native to the Mediterranean area but is now found in all temperate areas of the world. It was introduced in South Carolina from Turkey around 1830 by William Johnson and planted along the Alabama river as a forage plant. It has since spread aggressively and is considered invasive in many states including North Carolina. 

Johnsongrass is adapted to a wide variety of habitats including open forests, old fields, ditches and wetlands. It spreads aggressively by thick rhizomes and seeds that are produced in the hundreds and can form dense colonies that displace native vegetation and restrict tree seedling establishment. Sometimes this grass invades gardens and both the seeds and rhizomes can be transported and introduced into new areas in contaminated bags of topsoil.

The plant prefers full sun, moist to mesic conditions, and fertile loamy soil. However, this robust grass is easy to grow in a wide range of soil types and tolerates drier locations and soil containing gravel or clay. Most growth occurs during the summer and episodes of hot dry weather are tolerated.  Classified as a short-day plant, it does not flower if the daylight hours exceed about 13 hours per day. 

Control is difficult but herbicide applications applied early summer prior to seed formation and repeated for several years have shown some success.

Insects, Diseases, and Other Plant Problems: No known insect or disease problems. The pollen is known to induce hay fever. In riparian and other areas where Johnsongrass is highly productive, Johnsongrass may promote fire spread by increasing fine fuel loads above historical levels. This plant is listed as a noxious weed in 19 states including NC See native alternatives to the left.

 

See this plant in the following landscape:
Cultivars / Varieties:
Tags:
#invasive#poisonous#high maintenance#fast growing#aggressive#herbaceous perennial#tall grass#weedy grass#perennial weeds#weed
 
Cultivars / Varieties:
Tags:
#invasive#poisonous#high maintenance#fast growing#aggressive#herbaceous perennial#tall grass#weedy grass#perennial weeds#weed
  • Attributes:
    Genus:
    Sorghum
    Species:
    halepense
    Family:
    Poaceae
    Life Cycle:
    Perennial
    Recommended Propagation Strategy:
    Division
    Seed
    Country Or Region Of Origin:
    Eastern Mediteranean and Middle East
    Distribution:
    throughout
    Fire Risk Rating:
    high flammability
    Wildlife Value:
    pasture grass
    Particularly Resistant To (Insects/Diseases/Other Problems):
    drought
    Edibility:
    Low toxicity if eaten. Seed cam be eaten in small quantities raw or cooked. Used whole in a similar manner to rice or millet, or ground into a flour for bread, cakes.
  • Whole Plant Traits:
    Plant Type:
    Herbaceous Perennial
    Poisonous
    Weed
    Habit/Form:
    Arching
    Dense
    Erect
    Spreading
    Growth Rate:
    Rapid
    Maintenance:
    High
    Texture:
    Coarse
  • Cultural Conditions:
    Light:
    Full sun (6 or more hours of direct sunlight a day)
    Soil Texture:
    Clay
    High Organic Matter
    Loam (Silt)
    Shallow Rocky
    Soil pH:
    Acid (<6.0)
    Alkaline (>8.0)
    Neutral (6.0-8.0)
    Soil Drainage:
    Moist
    Occasionally Dry
    Available Space To Plant:
    Less than 12 inches
    NC Region:
    Coastal
    Mountains
    Piedmont
    USDA Plant Hardiness Zone:
    6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b, 10a, 10b
  • Fruit:
    Display/Harvest Time:
    Spring
    Fruit Type:
    Capsule
    Fruit Length:
    < 1 inch
    Fruit Width:
    < 1 inch
    Fruit Description:
    Seeds ripen September and October. Capsules are 1 inch with husk and 1/2 inch without.
  • Flowers:
    Flower Color:
    Brown/Copper
    Flower Inflorescence:
    Panicle
    Raceme
    Flower Bloom Time:
    Fall
    Summer
    Flower Size:
    < 1 inch
    Flower Description:
    Each panicle is up to 18 inches long and 9 inches wide, broader toward the bottom than the top and somewhat airy in appearance when fully open. The inflorescence is a panicle with branches tipped by a raceme. The panicle is lanceolate, or pyramidal. Primary panicle branches whorled at most nodes; moderately divided. Individual spiklets are 4.5-5 mm. long
  • Leaves:
    Leaf Color:
    Green
    White
    Leaf Feel:
    Smooth
    Leaf Type:
    Sheath
    Leaf Arrangement:
    Alternate
    Leaf Shape:
    Lanceolate
    Leaf Margin:
    Entire
    Hairs Present:
    Yes
    Leaf Length:
    > 6 inches
    Leaf Width:
    1-3 inches
    Leaf Description:
    Leaves occur primarily along the lower half of each stem. The leaf blades are up to 24 inches long and 1 to 3 inches across; they are widely spreading, arching, or ascending. The upper blade surface is medium to dark green, while the lower blade surface is more pale; both are smooth. The larger leaf have prominent central veins that are pale-colored. The junctions of leaf blades and sheaths have narrow strips of fine white hairs. Leaves occur primarily along the lower half of each stem.
  • Stem:
    Stem Color:
    Green
    Stem Is Aromatic:
    No
    Stem Cross Section:
    Round
    Stem Form:
    Straight
    Stem Surface:
    Smooth (glabrous)
    Stem Description:
    The stems are light green, terete, and glabrous. Each culm terminates in a panicle of spikelets.
  • Landscape:
    Resistance To Challenges:
    Drought
    Dry Soil
    Problems:
    Invasive Species
    Problem for Horses
    Weedy
  • Poisonous to Humans:
    Poison Severity:
    Low
    Poison Symptoms:
    Causes low toxicity in humans if the leaves are eaten, which can occur if the plant is mixed with, or mistaken for, grain sorghum. There have been no known cases of human poisoning. The foliage that becomes wilted from frost or hot, dry weather can contain sufficient amounts of hydrogen cyanide to harm cattle and horses if it is eaten in quantity. Young plants are more toxic than mature ones
    Poison Toxic Principle:
    Cyanogenic glycoside, hydrocyanic acid
    Causes Contact Dermatitis:
    No
    Poison Part:
    Leaves