Grassy Weeds - St Augustine Lawn - Broadleaf Signalgrass
BES-TEX WEED ID GUIDE · GRASSY WEEDS
Broadleaf Signalgrass
Brachiaria platyphylla (now Urochloa platyphylla)
Common Name
Broadleaf Signalgrass
Latin Name
Brachiaria platyphylla (Griseb.) Nash
(Urochloa platyphylla)
Family
Gramineae (Poaceae)
Life Cycle / Type
Annual · Grass
What Is It?
Broadleaf signalgrass is a spreading, highly branched summer annual that roots at the lower nodes. The leaf blade is short and wide, smooth on both surfaces, and often partly folded or creased near the tip. Spikelets sit on the underside of two to six ascending branches, set at an angle that looks like a signal flag. It reproduces by seed and may be common during turfgrass establishment. It is found from North Carolina into Florida and west to Oklahoma and Texas.
Leaf Shape Identification (Quick ID)
Broadleaf Signalgrass (Brachiaria platyphylla)
- Leaf tip: Creased near the tip
- Short, wide blade, widest near the base and tapering to the tip
- Blade smooth on both surfaces; hairs only on the edges and collar area
- Ligule a narrow membrane fringed with hairs
- Hairy sheaths
- Seedhead of 2 to 6 branches set like a signal flag
One-Sentence Counter Script“If the leaf is short, wide and smooth with hairs only on the edges, and it roots at the nodes, it is broadleaf signalgrass.”
Soil Temperature & Germination
Broadleaf signalgrass is a summer annual that comes up from seed.
[PLACEHOLDER]
Germination soil temperature for this species is not stated in the cited sources.
About 55°F
AgriLife guidance: soil temperature for spring pre-emergent timing against summer annual weeds (several days at this temperature).
Decision Question
Is the signalgrass visible above the soil right now?
Why This Weed Comes Back
Reproduces by seed
Common during turfgrass establishment
Roots at the lower nodes as it spreads
Learn the Basics
A healthy, thick lawn is the best defense against weeds.