Before we are moved into the garage or basement, we need to undergo a crucial preparation phase. Suddenly shifting us from the mild outdoor autumn air to a dark, cool space is a severe shock to our systems. You must help us "harden off." This means, about 6-8 weeks before the first expected frost, you should stop fertilizing us. The high nitrogen in fertilizer encourages tender new growth that is highly susceptible to cold damage. Then, a few weeks later, gradually reduce watering. This signals to us that our active growing season is ending, and we should begin to slow our metabolic processes. It’s our cue to start entering a state of dormancy.
Next comes the pruning. This may look drastic to you, but for us, it is a necessary survival tactic. You should cut our stems back to about 6 inches in height. Be sure to remove any remaining leaves, flowers, and flower buds. This serves two vital purposes for our winter survival. First, it drastically reduces the surface area from which we lose precious water through transpiration. Second, and just as importantly, it removes material that is most likely to rot, mold, or harbor pests. A decaying leaf touching a stem in a humid, stagnant environment is an invitation for disease that could kill us over the winter.
Our needs during dormancy are simple but non-negotiable. The garage or basement you choose must be cool, but not freezing. Our ideal temperature range is between 40-50°F (4-10°C). If the space gets much colder, the soil in our pots can freeze, and the ice crystals will rupture our delicate root cells, causing fatal damage. If it is too warm (above 60°F/15°C), we may be tricked into breaking dormancy prematurely. We will start to put out pale, weak, "leggy" growth in search of light, depleting our stored energy reserves long before spring arrives.
The space must also be dark. Light will stimulate growth, which we must avoid. As for water, our needs are minimal but critical. Our roots must not be allowed to dry out completely and become desiccated, but they absolutely cannot sit in wet soil. Soggy, cold soil leads to root rot, which is a death sentence. The goal is to keep the soil just barely moist. You should check on us about once a month. Stick your finger an inch into the soil; if it feels completely dry, give us a very small amount of water—just enough to lightly moisten the soil around the root ball. Do not drench us.
There are two primary ways you can overwinter us. The first, and simplest, is to leave us in our pots. After pruning, you can place our pot in the garage or basement. Some gardeners find it beneficial to lay the pot on its side to prevent water from pooling on the surface. The second method is the "bare-root" approach. This involves carefully removing us from our pot, gently shaking off most of the soil from our roots, and then placing us in a cardboard box filled with a slightly moist material like peat moss, vermiculite, or sawdust. The box should be left open. This method saves space and can reduce the risk of soil-borne diseases, but it requires more care to ensure our roots do not dry out completely.
As winter wanes and daylight increases, usually around late March or early April, it will be time to wake us up. This must be a gradual process. First, bring us into a warmer, well-lit area like a greenhouse or a bright windowsill. You can repot us if we are bare-root or if we have outgrown our previous pot, using fresh potting mix. Begin watering us more thoroughly, allowing the water to drain freely. Once you see signs of new growth emerging from our stems, you can start a very diluted fertilizer regimen to support this new development. Do not put us outside until all danger of frost has passed and you have gradually acclimated us to the outdoor conditions over a week or two, a process known as "hardening off."
