How Do Dianthus Reproduce?

Seeding Dianthus

• Dianthus plants produce seeds that grow readily when handled properly. Seeds from heirloom dianthus varieties, which are open pollinated, produce plants identical to the parent. Conversely, seeds from hybrid plants may result in plants slightly different than the parent plant. To obtain seeds, leave the flowers on a plant until they dry and the central, green part darkens and rattles slightly when shaken. This indicates that the seeds it contains are dry enough to germinate. You can save seeds for later use, keeping them sealed in a container in a cool, dark place, such as a refrigerator. Sow them in moist, soil-less mix or any sterile potting soil, giving them mild bottom heat for best germination. Seeds usually germinate in 5 to 10 days, but they may take up to 4 weeks, depending on conditions.

A Chip off the Old Block

• Another reproduction method that produces new dianthus plants genetically identical to the parent plant involves rooting healthy stem cuttings. The best time to take cuttings is after flowering, from plants that have been regularly dead-headed to force their energy into making strong vegetative growth. Choose green, non-woody stems and take cuttings on a cloudy day from well-watered plants. Make a sharp, 45-degree-angle cut to remove a stem piece that has four or five pairs of leaves, disinfecting the blade in 10 percent bleach between cuttings. After removing the leaf pair nearest the cut, place the cutting in moist sand or sterile potting soil. Cover the container with a plastic bag, keep the potting medium moist and expect new growth in a few weeks.

Layering for Replicas

• Many types of dianthus plants, including pinks and border carnations,can reproduce replicas of the parent plant through a process called ground layering. As the plant spreads, stems that droop and touch the moist ground sometimes take root, eventually producing new young plants. You can take advantage of this natural behavior: Choose healthy stems on one-or-two-year-old plants, make a tiny slit in the stem's surface with a razor blade between two nodes. Gently bend the stem outwards, push the cut area of stem under the soil and secure it with a piece of bent wire pushed over it and into the ground. After a week or two, a newly rooted plantlet that's identical to the parent forms, which can be cut free and transplanted.

Colors All Around

• Several different species of dianthus make attractive garden plants that can be easily reproduced by these methods. The variety called pinks is a biennial or perennial in U.S. Department of Agriculture plant hardiness zones 6 through 9, although it also grows as an annual. About 6 inches to 1 foot tall, its flowers are white, pink, red or bicolor. The border carnation, which is about 1 or 1 1/2 feet tall and grows in USDA zones 5 though 9. Many different cultivars are available, in colors that include yellow, salmon, pink, red and purple. The sweet William is another dependable bloomer that's 1 or 2 feet tall, with flower clusters rather than single blossoms. It grows in USDA zones 3 through 9 and attracts hummingbirds and butterflies.