As a carnation plant, the arrival of winter signals a period of profound challenge. We are not as deeply dormant as some perennials, nor are we as fragile as true annuals. Our survival hinges on a delicate balance of preparation and protection. To ensure we emerge vibrant and healthy in the spring, here is a detailed guide from our perspective.
Before the first hard frost even threatens, our internal systems begin a crucial process called hardening off. As temperatures gradually drop in late autumn, we slow our growth and begin moving sugars and other compounds into our cells. This acts like a natural antifreeze, lowering the freezing point of the water within our tissues. The goal is to avoid the formation of large, sharp ice crystals that can puncture and destroy our cell walls, which is a primary cause of frost damage. A sudden, severe cold snap is far more dangerous than a gradual descent into colder weather because it does not give us adequate time to complete this vital process.
Our crown—the point where our stems meet the roots at the soil surface—is one of our most vulnerable parts. A deep freeze here can be fatal. Therefore, applying a thick, dry layer of mulch around our base is one of the most beneficial actions you can take. Suitable materials include straw, pine needles, shredded bark, or even a fluffy layer of fallen oak leaves. Please apply this blanket after the ground has frozen hard for the first time, typically in late autumn or early winter. The purpose is not to keep us warm, but to keep the ground consistently frozen, preventing the damaging cycle of freeze-thaw-freeze that can heave our roots right out of the soil.
While our roots are protected below ground, our above-ground foliage can suffer from direct frost contact, especially for less hardy varieties. On nights when a frost is forecast, a simple covering can make a significant difference. Drape a breathable fabric like burlap or an old sheet over us, ensuring it extends to the ground. It is critical to avoid using plastic sheeting directly on our leaves, as it can trap damaging moisture and, if the sun hits it, create an oven-like effect. Remember to remove these coverings once the morning sun has warmed the air the next day.
Our water needs change dramatically as we enter our semi-dormant state. In the weeks leading up to winter, you should gradually reduce watering. Our soil should be moist but never soggy. Wet, cold soil is a recipe for root rot, which is often more deadly than the cold itself. Furthermore, you must cease fertilization by mid-autumn. Fertilizer encourages tender, new growth, which is highly susceptible to frost damage. We need to focus our energy on fortifying existing structures, not producing new, vulnerable shoots.
For those of us living in containers, our situation is more precarious. Our roots are completely exposed to the ambient air temperature, unlike our in-ground counterparts who benefit from the earth's insulating mass. Before a hard freeze, our pots should be moved to a sheltered location, such as an unheated garage, a cold frame, or against a south-facing wall of a building. Alternatively, you can insulate the pot itself by wrapping it in bubble wrap or burlap and then grouping several pots together. Raising the pot off the cold ground on "pot feet" or bricks can also improve drainage and reduce heat loss.
