Tuesday, July 1, 2008

Turf - Weed Indicators

Weeds that are prevalent in turf or landscapes can be indicators of problems or conditions that need to be managed. Correcting these problems can reduce the need for other weed control measures. The following are examples.

Low mowing height can be indicated by proliferation of annual bluegrass, bentgrass, bermudagrass, crabgrass, mallow, purslane or other low growing weeds. Acid soil indicators include red sorrel and bentgrass. Compacted soil is often indicated by the presence of prostrate spurge, knotweed, goosegrass, chickweeds, or bermudagrass. Low fertility soils often have more plantains, red sorrel, brome species, and if enough moisture, white clover. Black medic, carpetweed, red sorrel and sandbur are indicators of dry soil. Wet soils often have yellow nutsedge, annual bluegrass or other bluegrasses, bentgrass, chickweed, crabgrass, ground ivy, speedwells, or violets growing on them. Excess shade is indicated by annual bluegrass, rough bluegrass, chickweed, ground ivy, nimblewill, or violets. Moss is found in moist, shady, and acid sites. High fertility soils often have a proliferation of weeds such as crabgrass, bermudagrass, and bluegrasses (annual and perennial). Soils that have recently been seeded often have foxtails, crabgrass, and many annual broadleaf weeds.

Gordon Johnson, Extension Horticulture Agent, UD, Kent County

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