With their greyish-green foliage and colorful pastel blooms, carnations are a familiar old-fashioned favorite. Although they aren't difficult to grow, carnations, like all perennials, can become crowded over time. Crowding limits air circulation to the carnation's roots, as the carnation struggles for adequate water and nutrients. Tired, crowded carnations can be rejuvenated by dividing the plants and giving them a new start. To keep carnations at their blooming best, divide the plants in early spring every two to three years.
Prepare a planting spot for the divided carnations ahead of time. A well-drained spot is crucial for carnations, so don't select a spot where water puddles for more than four or five hours. Choose a spot where the carnations will be in sunlight for four to five hours each day. Cultivate the soil to a depth of 8 to 10 inches. Remove roots and rocks, and break apart large dirt clods.
Dig up the entire clump of carnations that you plan to divide. Dig a few inches away from the plant so you don't cut into the roots, then rock the shovel back and forth to loosen the roots before lifting the clump of carnations out of the ground.
Discard the older, middle part of the plant if it looks bedraggled, along with any areas that have rotten or soft roots. Divide the clump into smaller segments with your hands, teasing the roots apart carefully with your fingers. Each segment should have at least three shoots and several healthy roots.
Dig a hole in the prepared area for the newly divided carnations. Plant the carnation so that the top of the roots is level with the surface of the soil. Never bury the crown of the carnation or any part of the stems.
Water the carnations thoroughly after planting, and keep the soil damp for several weeks so the newly divided carnation can develop a healthy root system. Although the soil should be moist, don't water to the point that the soil is soggy, because too much water can cause the foliage to turn yellow.
Feed carnations every six to eight weeks, using a general purpose water-soluble fertilizer. Read the package label for specific amounts.