Carnations, perennial flowering plants native to Europe and Asia, produce double, ruffled, sweetly scented flowers that last up to two weeks when cut. One of the top commercially produced flowers in the United States, carnation flowers provide dramatic contrast in flower arrangements and bouquets. Blooms appear in shades of pink, purple, red, orange, white and yellow during the spring through mid-fall. When not in bloom, carnations have an open, irregular and not particularly interesting growth habit. Most varieties reach up to 20 inches in height and require only minimal care to thrive in the home landscape. Hardy in zones 6 through 11, carnations perform as annuals in colder zones.
Plant carnation flowers during early spring after all danger of frost has passed. Choose a location that receives bright sunlight throughout the day. Spread a 2-inch layer of organic compost over the entire site, then use a garden spade to work it into the soil prior to planting.
Dig a hole at the planting site just large enough to encompass the plant's root ball. Insert the roots into the hole and gently cover with soil. Leave some of the plant's crown exposed to prevent rot. Water lightly to compact the soil around the roots.
Water carnation flowers whenever the surface of the soil feels dry to the touch, about once every week. Soak the soil to a depth of about 6 inches to ensure the roots receive plenty of water. Do not allow any standing water to accumulate around the plant, or rotting may occur.
Feed the plants once every six to eight weeks using a low-phosphorus 20-10-20 NPK liquid fertilizer to provide proper nutrition for root and flower development. Apply following the manufacturer's directions for the best results. Do not feed during winter.
Remove spent carnation blossoms throughout the flowering period to encourage the plant to form additional flowers. Pinch off the old blossoms at their point of origin to minimize damage and prevent disease.
Cut the plant stems back to ground level after all flowers have died to help the plant conserve nutrients and prepare for the oncoming winter. Spread a 3-inch layer of mulch over the plant just before the first frost of winter, and remove the mulch after the final frost of spring.