Carnations are favorite flowers for corsages, bouquets, boutonnieres and floral arrangements because they are so long-lasting. These sturdy but pretty flowers are native to Europe and Asia. While carnations were used in the past as an herbal treatment for stomach aches and fever, today they are grown merely as ornamental plants that brighten up the garden. Carnations are perennials, but are treated as annuals in USDA hardiness zones north of Zone 6.
Carnations belong to the genus Dianthus, which is derived from the Greek words for "god" and "flower." Their nickname "pinks" comes from a sewing term; to pink a fabric, or to use pinking shears, is to cut a jagged edge in order to reduce raveling. Carnations have fringed petals that resemble this trim.
Carnations have linear, opposite leaves ranging from dark green to gray green. Their flowers, which have a very strong fragrance, come in various shades of yellow, pink, purple, light green, salmon, fuchsia and bi-color. Carnations grow from 10 to 20 inches high, with a spread of 8 to 15 inches, depending on the cultivar.
Carnations require 4-5 hours of full sun each day. They grow best in fertile, well-drained soil that has a slightly alkaline pH. Water carnations once a week, or when the soil is dry, at least 1 inch below ground level. Too much water will cause carnations' leaves to yellow.
Carnations require good air circulation. Plant at least 10 to 12 inches apart, and do not mulch. Feed the plants every two months with a general 20-10-20 liquid fertilizer.
Carnations can be propagated by seed, cuttings and division. Sow carnation seeds 1/8 inch deep in the spring, after all danger of frost has passed, or early summer. They most likely will overwinter and not bloom until the following year. If you want to start seedlings in the winter, freeze the seeds for a week, starting about 9 weeks before the last frost date. Carnations take about 2-3 weeks to germinate.
To propagate by division, gently dig up the plant in the fall. Separate the clumps and transplant. Be sure you don't bury the crown, as this will kill the plant.
Carnations are tough plants, but slow drainage, overwatering, crowding and poor air circulation can lead to bacterial leaf spot, root rot and powdery mildew. These are easily remedied by fixing the unhealthy conditions.