Louisiana Yards and Neighborhoods Weed Management

Weeds Plants growing out of place Compete with lawns and landscape Water Nutrients Light Plants growing out of place Compete with lawns and landscape Water Nutrients Light Dandelion Thistle Common chickweed

Types of Weeds Broadleaves –Netted veination –2 cotyledons –Taproot –Showy flowers Grasses –Parallel –1 cotyledon –Fibrous roots Sedges –“Nutgrass” –Triangular stems –Leaves in 3s Broadleaves –Netted veination –2 cotyledons –Taproot –Showy flowers Grasses –Parallel –1 cotyledon –Fibrous roots Sedges –“Nutgrass” –Triangular stems –Leaves in 3s White clover Dallisgrass 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 – 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 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 May cause allergies in humans Host for diseases Insects May cause allergies in humans Poison ivy

Indicator Weeds Soil condition Soil compaction Low nitrogen Poor drainage Soil condition Soil compaction Low nitrogen Poor drainage Indicator weeds Goosegrass, annual bluegrass Clovers Dollarweed, sedges, doveweed Annual bluegrass Annual bluegrass White clover 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. #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 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 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