Johnsongrass is a tall, aggressive perennial grass with thick rhizomes. In lawns that are mowed regularly it stays short, but it shows up along fences, edges, and neglected areas.
- Scientific name
- Sorghum halepense
- Type
- Warm-season perennial grass
- Most visible
- May–October
How to Identify Johnsongrass
- Wide blades with a prominent white midrib
- Thick, white, spreading rhizomes
- Large, open, purplish seed heads if left unmowed
- Can grow several feet tall
When It Shows Up in Oklahoma Lawns
Emerges in spring from rhizomes and spreads by both seed and underground stems, especially in lots and fence lines.
How to Control Johnsongrass
- Mow regularly to weaken it
- Dig out rhizomes in beds
- Spot-treat with a labeled herbicide in non-turf areas
- Don't let it go to seed