Sorghum halepense
grassy weedUSDA zones 5–10Active: spring, summerTall, aggressive perennial grass that spreads by thick rhizomes. One of the most problematic grassy weeds in southern lawns and landscapes.
Very tall (3-7 feet); wide leaves with white midrib; large, open, reddish-purple seed heads; thick rhizomes.
Frequent mowing weakens rhizome reserves over time. Mow before seed heads form.
When: Mow every 5-7 days during active growth
Cover patches with clear plastic for 6-8 weeks. Deep rhizomes may survive.
When: Apply during hottest summer months
No selective option for turf. Carefully spot-treat and reseed.
When: Apply when 12-18 inches tall and actively growing; reseed after 7 days
Active ingredient: Glyphosate — e.g. Roundup
Grass safety: always match herbicides to your grass species — products safe on Kentucky bluegrass can kill St. Augustine or centipede. Lawn Guardian checks this automatically against your lawn profile.
Lawn Guardian turns this guidance into a schedule timed to your USDA zone and this week's actual weather — and adapts every time you log what you've done.
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