Lawn Maintenance & Weeds

Annual Weeds

• Winter and summer annual weeds, such as spurge, knotweed, chickweed, crabgrass and foxtails, grow, flower and produce seed in one season. Preventing them from shedding their seed is the best goal for lawn maintenance. Corn gluten pre-emergent herbicide is effective on annual weeds. Apply it in early spring to prevent weed seed germination. Mowing with the blades set at a high level reduces annual weed growth and prevents weed seed set. High mowing preserves lawn grass crowns and cuts off the top of the weed plants, which is their growing point. Do not fertilize heavily in spring when many annual weeds begin their growth season.

Perennial Weeds

• Dandelion, quackgrass, clover, Canadian thistle, yellow nutsedge and plantains are perennial weeds that return each year from a crown and root system that spreads by underground rhizome or seed. Bulblike rhizomes spread by rerooting. Cut as much of the dandelion root as possible in early spring and continue this as new growth appears. It eventually stops sending up new leaves from the root system. Patches of perennial weeds are effectively controlled with spot treatments of glyphosate-type herbicides.

Feed the Soil

• Lawn grass consumes much nitrogen. Leaving grass clippings on the lawn provides a good nitrogen source. Lawns need 17 nutrients from the soil for healthy grass to grow. Mature compost added in the fall provides nutrients to the soil in slow-release during winter. The microorganisms in homemade or commercial mature compost are the source of the 17 required nutrients. The healthier the soil and grass, the fewer weeds will grow.

Watering Techniques

• Water the grass deeply and infrequently. Grass develops roots longer than weed roots when irrigated once a week or less. Frequent shallow watering, as with many sprinkler systems, encourages weed growth. Native grass, such as buffalograss and blue grama, have greater leaf density and are more effective in crowding out weeds than traditional Bermudagrass. Maintenance of native grass lawns also requires less frequent mowing and watering.