Louisiana Yards and
Neighborhoods
Weed
Management
www.lsuagcenter.com/lyn
Weeds
• Plants growing out of place
• Compete with lawns and
landscape
• Water
• Nutrients
• Light
Common chickweed
Thistle
Dandelion
Types of Weeds
• Broadleaves
– Netted veination
– 2 cotyledons
– Taproot
– Showy flowers
White clover
• Grasses
– Parallel
– 1 cotyledon
– Fibrous roots
Dallisgrass
• Sedges
– “Nutgrass”
– Triangular stems
– Leaves in 3s
Purple nutsedge
Why So Many Weeds?
Seed Production
•
•
•
•
Pigweed – annual broadleaf
13,000 – 100,000 seeds/year
Dormancy – survive 30 years
Don’t allow seed production
Pigweed
Pigweed - heavy seed producer
How Do Weeds Spread?
1) Nature
• Animals and birds
• Winds – dandelion
• Rains and flooding
• Some type of runner – rhizome, stolon
2) Humans
• Impure seed/sod
• Compost and mulch
• Machinery – contaminated mowing equipment
• Contaminated soil
Weeds in Lawns & Landscape
• Host for diseases
• Insects
Poison ivy
• May cause allergies in humans
Indicator Weeds
Soil condition
• Soil compaction
• Low nitrogen
• Poor drainage
Annual
bluegrass
White clover
Indicator weeds
• Goosegrass, annual
bluegrass
• Clovers
• Dollarweed, sedges,
doveweed
Dollarweed
Doveweed
Cultural Practices That Improve
Turf & Ornamentals
Discourage competition
from weeds
Virginia Buttonweed
• #1 weed in lawns
• Perennial
• Common in lawns mowed too low
• Highly drought-tolerant
• Reproduces by seed, stem
fragments, etc.
Dallisgrass
• Perennial - stubby
rhizomes
• Common throughout
the South
• Tolerates low mowing
and drought
• More cold-tolerant than
lawn grasses
Chamberbitter
• Summer annual
• Reproduces by seed
• Each fruit contain 6
seeds
• Quite common in
flower beds
Dollarweed
•
Perennial
•
Reproduces by seed
and rhizomes
• Common in wet areas
•
Infests thin lawns
Florida Betony
• Perennial plant
• Very invasive weed in landscapes
• Square stem
• White to pink flowers
• Reproduces quickly by tubers and
seeds
Weed Management
• Proper lawn and
landscape cultural
practices first
• Identify weeds
• Calibrate sprayers and
spreaders
• Read and understand
herbicide labels
Louisiana Yards and
Neighborhoods
Weed
Management
www.lsuagcenter.com/lyn