The question of whether carnations come back every year is a fundamental one in gardening, and the answer lies in understanding the plant's biological life cycle. From a botanical perspective, the longevity of a carnation plant is primarily determined by its genetic makeup, which dictates whether it is classified as an annual, a perennial, or a biennial. The climate in which it is grown then acts as a modifying factor, influencing how these genetic traits are expressed.
At their core, carnations (Dianthus caryophyllus) are technically short-lived perennial plants. This means that, given the right environmental conditions, a single plant possesses the genetic ability to live for more than two years, regenerating from its root system each spring. However, the extensive cultivation and hybridization of carnations for specific ornamental traits have resulted in varieties that behave differently. Therefore, the answer is not uniform across all types.
Many popular garden carnations fall into the perennial category. These include varieties like Border Carnations and most modern hybrids such as the 'EverLast' or 'SuperTrouper' series. From a plant's point of view, perennial carnations have evolved survival structures—specifically a woody, branched crown at the soil line. After flowering, the above-ground growth may die back, especially in colder winters, but the crown and root system remain alive in a dormant state. As temperatures warm and daylight increases in spring, these plants channel stored energy from their roots to produce new shoots and leaves, effectively "coming back" year after year. They are typically hardy in USDA zones 4-8, though this varies by cultivar.
Some carnations are genetically programmed as annuals. These plants complete their entire life cycle—germination, growth, flowering, seed production, and death—within a single growing season. From the plant's perspective, its sole purpose is to flower prolifically to set seed and ensure genetic propagation before environmental conditions become fatal. Florist's carnations, while technically perennials in their native Mediterranean climate, are often grown as annuals in much of the US because they are not cold-hardy. Furthermore, many seeds sold to home gardeners are for annual varieties that are bred for rapid, showy blooms in their first year but lack the robust root system needed to survive winter.
A plant's genetic potential is only realized within a suitable environment. A perennial carnation's ability to return is heavily dependent on winter hardiness. In the southern US (e.g., zones 9-10), winters are mild enough that many carnations remain evergreen and continue growing. In the northern US (e.g., zones 3-4), even perennial types may perish without a protective layer of mulch or snow cover because severe freezing temperatures can damage the crown and root tissues beyond recovery. Conversely, in very hot and humid southern climates, perennial carnations may struggle with the summer heat and act as short-lived perennials, lasting only two or three years before declining.
Less common but still relevant are biennial carnations. These plants have a two-year biological cycle. In the first year, the plant focuses its energy on vegetative growth, producing a low rosette of leaves. It overwinters in this form and then, in the second year, it bolts—sending up a flowering stalk, setting seed, and subsequently dying. This strategy is an adaptation for surviving a cold winter as a small, hardy plant before investing energy in reproduction.
