With more than 300 different species and hundreds of hybrid varieties available, carnation plants are a favorite for home gardeners in USDA zones 4 through 9. Carnation blossoms are one of the longest lasting cut flower blooms, emitting an enticing, spicy clove fragrance. Traditional carnation plants grow to a height of 18 to 24 inches, but with the abundance of hybrids, you can now find a wide range of colors and sizes, including low-growing border carnations. Part of the larger Dianthus family, carnations can be grown from seeds or cuttings. Carnation plants generally will produce flowers for three years before you need to replace the plant.
Carnation varieties can range from single stem blooms, to spray stems with multiple blossoms on one stem, and dwarf carnations that are often used as borders. To promote continuous flowering, side stem shoots that do not have bud formation are removed. This directs the energy of the plant to developing and forming flower buds instead of new stem growth.
Non-flowering shoots on carnation plants will develop as side shoots at the base of the plant. These shoots are often referred to as lateral shoots. The lateral shoots are new growth and will not immediately develop flower buds until the shoot grows significantly in length.
As a healthy carnation plant grows, it will expand both horizontally and vertically. The nonflowering, lateral shoots are the process by which this happens. But there is a propagation function to these lateral shoots. By either cuttings or layering, the nonflowering shoots of a carnation can be propagated to form a new carnation plant. Select healthy side shoots to cut off the mother plant and trim the lower leaves off the stem. Dip the cut stem end in a rooting compound, then plant in a sandy soil, or nonsoil medium, to root the cutting. Layering is easily done by first removing several inches of carnation leaves from the lower part of a lateral shoot. Then gently bend the shoot to the ground and cover the leafless section of the shoot with garden soil. Soon new roots will develop on the layered shoot, resulting in a new carnation plant.
Using the nonflowering shoots of a carnation plant to propagate new plants should ideally be done in the late spring, during April, May and early June. This is because the plant has not yet begun to put its energy into forming buds on shoots, so the shoots will have energy to form new roots.
There are benefits to using the nonflowering lateral shoots of your carnation plant for propagation. Cuttings and layering carnation shoots is easy and plants develop much faster than starting carnation plants from seeds. In fact, the only way to grow new carnation plants that are identical to the original hybrid carnation variety is by cuttings or layering lateral shoots.