These little yellow weeds are very common and seem to be present in nearly every lawn in Maryland and Northern Virginia. Dandelions are a perennial weed that spreads seeds prolifically. The flowers of the dandelion are bright yellow and later dry to become the familiar white balls of fluff that easily blow in the wind. A single plant can spread seeds over hundreds of yards. Pre-emergents used in late winter or early spring will prevent dandelions from emerging. The best way to eliminate dandelions by maintaining a thick, lush lawn.