Broadleaf signal grass is a weedy annual native ornamental grass in the Poaceae (grass) family. Whether this plant is native to the SE USA or introduced and naturalized to this area is in dispute. It is a warm-season grass that grows and blooms from May through October. It is found along roadsides, disturbed areas, agricultural fields, and ditches preferring loamy to sandy soils. It is not recommended for most gardens . Its form is a graminoid, elongated culms with blade-like leaves. It is commonly found growing along the ground with ascending tips. Its roots are fibrous and can often root at the lower stem nodes. Seedlings may have maroon edged and hairy leaf sheaths. Insects, Diseases, and Other Plant Problems: It can be resistant to herbicides and therefore difficult to manage.
Curated pairwise relationships between this plant and others in the library — who feeds
whom, who competes, who confuses the pests. Green reads as a good pairing, red as one to avoid.
No curated interactions recorded for this species yet.
Also noted by NC State
Related species the NC State Plant Toolbox flags for this plant — look-alikes to tell
apart, and plants that play a similar role in a planting. Ones we carry in the library are linked.
Annual; Native Plant; Ornamental Grasses and Sedges; Weed
Life cycle
Annual
USDA zones
7a, 7b, 8a, 8b, 9a, 9b, 10a, 10b, 11a, 11b
Light
Full sun (6 or more hours of direct sunlight a day) | Partial Shade (Direct sunlight only part of the day, 2-6 hours)
Soil texture
Loam (Silt); Sand
Soil pH
Acid (<6.0); Neutral (6.0-8.0)
Soil drainage
Good Drainage
Available space
12 inches-3 feet
NC region
Coastal; Piedmont
Growth rate
Medium
Maintenance
Medium
Canopy layer
4 - Herbaceous
Form & Appearance
Habit / form
Spreading
Texture
Medium
Leaf color
Green; Red/Burgundy
Leaf type
Sheath; Simple
Leaf arrangement
Alternate
Leaf shape
Linear
Leaf feel
Smooth
Leaf size
> 6 inches long, < 1 inch wide
Hairs present
Yes
Leaf detail
Sheathing wide linear leaves with hairs on sheath, blades are smooth. The Ligule, which is a narrow membrane, has a fringe of hairs. Leave blades can have a bit of Burgundy color. Leaf sheaths are hairy. Leaves may be crinkled on one side and smooth on the other.
Flower color
Green
Flower form
Raceme; Spike
Flower size
< 1 inch
Flower detail
The seed head is in the form of a raceme that blooms from May to October. The seed heads have 2 to 6 branchlike structures, each 1 to 3 1/2" long. The spikelets have a flattened look.
Bloom time
Fall; Spring; Summer
Fruit color
Brown/Copper
Fruit size
< 1 inch long, < 1 inch wide
Stem detail
The stems are prostrate, branching and bending at the nodes.
Wildlife & Ecology
Native status
Native
Origin
Southern and central U.S.A., Cuba, South America
Distribution
AL, AR, AZ, FL, GA, IL, KY, LA, MD, MO, MS, NC, OK, SC, TN, TX, VA