This dandelion was scuffed just prior to spraying a weedkiller. It died quickly and completely, never to return. The best time to spray dandelions is in the fall, because this is when plants are naturally shifting materials from leaves to roots for winter storage. Weedkiller applied in fall moves directly to roots, which helps get rid of dandelions permanently. Avoid using lawn weed and feed products in fall to kill dandelions, though, because if your lawn goes dormant for winter, it won't absorb the fertilizer. Instead, any weeds present take up the fertilizer and grow stronger.