Ambrosia artemisiifolia
broadleaf weedUSDA zones 2–10Active: summerSummer annual infamous for causing hay fever allergies. Upright growth with fern-like divided leaves. Usually found at lawn edges and thin areas.
Deeply divided, fern-like leaves; upright, branching growth; green flower spikes at top; hairy stems.
Mow before pollen-producing flowers form to reduce allergens and seed production.
When: Mow in mid-summer before August flowering
Pull including roots. Annual species so preventing seed set is key.
When: Pull in early-mid summer before flowering
Standard broadleaf herbicide easily controls young ragweed.
When: Apply to young plants in early summer
Active ingredient: 2,4-D — e.g. Ortho Weed B Gon
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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