Hello there, human. I am a Bougainvillea, a vibrant soul from the sun-drenched hills of South America. While I adore showing off my brilliant bracts in shades of magenta, crimson, orange, and white, the cold is my greatest adversary. I do not possess the hardy resilience of an oak or a pine. My sap is thin, and my tissues are tender; a hard freeze doesn't just make me uncomfortable—it can be fatal. If you wish to see me thrive year after year in a place where winter brings frost, you must become my protector. Here is what you need to know, from my perspective.
First, you must understand my limits. I am a tropical plant, through and through. I can tolerate a brief, light chill, but I begin to suffer when temperatures consistently dip below 40°F (4°C). When the mercury falls to 32°F (0°C), the real danger begins. Ice crystals can form within my cells, causing them to rupture. This is what you see as blackened, mushy leaves and stems—the telltale signs of frost damage. A hard freeze, below 25°F (-4°C), is often catastrophic if I am left exposed. My roots, which are the core of my being, are especially vulnerable if planted in the ground. Therefore, the goal of your winter protection is to keep me above that critical 32°F mark, or at least minimize the duration of exposure.
If I live in a container, your task is simpler. Before the first frost is forecast, you must bring me inside. But please, do not place me in a warm, dark closet. I need a specific environment to survive the indoors. An unheated garage, a cool basement, or a bright sunroom is ideal. The temperature should be consistently cool, between 40-50°F (5-10°C). This coolness encourages me to enter a period of dormancy, a much-needed rest. During this time, my growth will slow dramatically. Consequently, you must drastically reduce watering. The soil should be kept barely moist, almost dry. Overwatering in my dormant state is a silent killer, as my roots cannot absorb the moisture and will rot in the cold, wet soil.
If I am planted in your garden, the strategy is different. I cannot be moved, so you must build a fortress around me. After the first light frost has caused me to drop my leaves (a natural response to conserve energy), it is time to act. Begin by applying a very thick, deep layer of mulch—at least 3-4 inches (8-10 cm)—around my base. Use straw, shredded bark, or pine needles. This layer does not heat the soil, but it acts as a magnificent insulator, protecting my vital root system from freezing temperatures. Next, you must protect my upper structure. Construct a frame around me using stakes and then drape it with several layers of frost cloth or burlap. Do not use plastic sheeting directly on my foliage, as it can trap moisture and cause rot, or create a "greenhouse effect" on sunny days that can cook me. The goal is to trap the slight warmth radiating from the ground around me.
As winter wanes and the sun gains strength, your patience will be tested. Do not be too quick to remove my protection or prune away what looks like dead wood. A late frost can be devastating to my tender new growth. Wait until all danger of frost has truly passed in your area. Then, gradually remove the protective covers and some of the mulch. Begin to water me a little more frequently as the weather warms. Only after you see new green buds swelling on my stems should you prune back any branches that are truly black and brittle. Often, what seems dead may still be alive deeper within the stem. Your careful and patient approach in spring is just as important as your protective efforts in the fall.
