December, January and February are ideal months to apply herbicides to control this weed. Lawn burweed is small and easier to control at this time of the year than in April and May. Also, turfgrasses are not actively-growing during the winter months and have better tolerance to some herbicides.
The weed in question is most commonly lawn burweed (Soliva pterosperma), a.k.a. spurweed, stickerweed, sandbur, sanbur and sandspur. Lawn burweed is a winter annual member of the Aster family. The weed germinates in the early fall months as temperatures cool and remains small or inconspicuous during the cold winter months. However, as temperatures warm in the early spring, or about the same time as spring sports activities, lawn burweed initiates a period of rapid growth and begins to form spine-tipped burs in the leaf axils. The sharp-tipped spiny burs of this weed can irritate the skin.
See the UGA Pest Management Handbook for pesticide recommendations for your turf type. Two to three weeks after the initial application, lawn burweed control should be evaluated. If control is not acceptable, an additional application may be necessary.
Key identification characteristics of lawn burweed are:
Geranium carolinianum L. is a semi-erect 8-28 inch tall winter annual or biennial. It can be identified by the greenish-pink to red, densely hairy stems as well as its round to oval, hairy leaves, with blunt-toothed margins. Carolina Geranium can be found throughout the continental United States and Hawaii.
Oxalis stricta is a herbaceous perennial found in warmer climates and annual in cooler areas. Yellow Woodsorrel is identified by its green to yellow-green, alternating leaves, divided into three partly-folded, lobes appearing heart-shaped. It can be found in most of the Eastern and Central United States.
Phyllanthus urinaria L. is a warm-season annual broadleaf weed that is also known as gripeweed and little mimosa. Chamberbitter is identifiable by its two rows fo leaves arranged oppositely on branchlets. The leaves are thin, with smooth margins. Chamberbitter is found from Texas to Florida, as well as in the tropics.
Eragrostis ciliarisis an erect summer annual with smooth leaves that have hairs on the upper margins of the leaf sheaths. Gophertail Lovegrass can also be identified by its rolled venation. It can be found in New Jersey, south into Florida and west into Texas.
Kummerowia striata is a freely-branched summer annual legume with leaves that alternate with three egg-shaped to oblong, smooth leaflets with a short spur at the tip of each. Leaflets also have prominent mid veins with parallel veins. Common Lespedeza is common in the Southern Unites States, north to Pennsylvania and west to Texas, Kansas and Missouri.