Identifying and Managing Crabgrass, Bentgrass, and Dandelions

Crabgrass: The Persistent Summer Annual

Crabgrass (Digitaria spp.) is the most common lawn weed, thriving in midsummer heat when cool-season grasses are semi-dormant. It overwinters as seed, germinating around mid-May, and dies with the first hard frost. Crabgrass prefers full sun and forms clumps with radiating "arms" that smother surrounding turf. The best defense is a thick, vigorously growing lawn mowed no shorter than 2.5 inches for cool-season grasses. Bag clippings when seed heads are present to reduce spread. Avoid summer fertilization and use post-emergent herbicides after crabgrass has sprouted.

Bentgrass: A Weed in Home Lawns

Creeping bentgrass (Agrostis stolonifera) is a cool-season perennial used on golf greens but considered a weed in home lawns. It forms fine-textured, bright green patches with flat, narrow leaves. No selective herbicide removes bentgrass without damaging desirable turf. Physical removal—digging 1 inch deep and reseeding—is effective. If using glyphosate, apply to the patch plus a 6-inch buffer to kill creeping stems; wait 7 days before reseeding. If quackgrass rhizomes appear during tilling, remove them or wait for regrowth and treat again.

Dandelions: More Than Just a Weed

Dandelions (Taraxacum officinale) are broadleaf perennials with yellow flowers that turn into wind-dispersed seed heads. Though considered weeds, they have culinary and medicinal uses: leaves resemble mustard greens, roots are used as a diuretic and for treating anemia or nervousness, and flowers make dandelion wine. Uncontrolled dandelions rob soil moisture and nutrients, killing grass patches. Mowing flowers doesn't eliminate them. Spot-treat during active growth with broadleaf herbicides. Apply granular products to wet foliage for adhesion; spray liquids on calm days to prevent drift. Remember, broadleaf herbicides kill all broadleaf plants—protect desirable garden plants.