Knawel is a perennial broadleaf weed that is also called German Knot-grass, Annual Knawel and its scientific name, Scleranthus annuus.
Knawel can be identified by its low-growing to horizontal growth habit, as well as its extensive branching. Its leaves are sharply pointed at the tip and joined at the node by a translucent membrane. The leaves also may appear to be whorled when new shoots are expanding from leaf axils. Blooming from March through October, this broadleaf weed features small, petalless flowers with five green sepals.
This broadleaf weed grows in low-maintenance lawns most commonly anchored in dry, sandy soils. It is often found growing in thin lawns, glades and along railroads and roadsides. Knawel can be found throughout much of the United States.
Scleranthus annuus has a grass-like appearance and horizontal growth habit that often enables it to get established in lawns without being noticed. Additionally, cultural weed control methods, such as proper mowing, are largely ineffective because Knawel typically grows beneath normal lawn-mowing heights. Professionally selected and applied broadleaf weed killers—based on your specific climate and geography—are the most effective method for control.