From my perspective as a Lobelia, my ability to survive winter indoors is not a simple yes or no. It depends entirely on my specific type. Many of the popular bedding Lobelias, like the vibrant Lobelia erinus you see in hanging baskets, are tender perennials. This means my genetic code is programmed for a multi-year life cycle, but I lack any frost tolerance. I am native to milder climates and simply not equipped to handle freezing temperatures. However, if you understand my needs and replicate my ideal conditions, you can help me, a tender perennial, survive the winter indoors as a houseplant.
Before the first frost threatens, I need your help to transition. Abruptly moving me from the cool, bright outdoors to a warm, potentially dim house is a massive shock to my system. Please, bring me inside well before nighttime temperatures dip below 50°F (10°C). To make this move less stressful, give me a good pruning. Cut my stems back by about half to two-thirds. This serves two vital purposes for me: it reduces the overall mass of foliage that my roots will struggle to support in lower-light indoor conditions, and it encourages me to put my energy into becoming bushier and stronger, rather than sustaining long, leggy growth.
Once indoors, my survival hinges on you replicating my preferred conditions as closely as possible. Light is my most critical need. I crave bright, direct light for several hours each day. A south-facing window is my best chance. Without sufficient light, I will become etiolated—stretching out with weak, pale stems and sparse leaves in a desperate search for sun. I also prefer a cool environment. A warm, dry room is my nightmare. I thrive in temperatures between 50-70°F (10-21°C). A cooler sunroom, a bright bathroom, or a windowsill away from heating vents is perfect. Please keep me away from direct blasts of heat, as they will dry me out and stress me.
My watering needs change dramatically in the winter. My growth slows down significantly, a period you call dormancy, so my roots absorb moisture much more slowly. The goal is to keep my soil barely moist, but never soggy. Overwatering is the quickest way to kill me, as it will lead to root rot—a fatal condition where my roots suffocate and decay. Allow the top inch of soil to dry out between waterings. As for food, please stop fertilizing me entirely during the winter. I am not actively growing and cannot process the nutrients, which would only build up in the soil and potentially harm my roots.
Even with perfect care, I may face some struggles. The dry, indoor air is unnatural for me and can make me more susceptible to pests like spider mites, who thrive in such conditions. Please check my leaves regularly, especially underneath, and be prepared to rinse me off or use an insecticidal soap if you see any tiny webbing or speckling. I might also look a bit sad and leggy during the deepest winter months. This is normal. Withhold the urge to overwater. With patience and the return of stronger spring light, I will begin to put out vigorous new growth, ready to be hardened off and eventually returned to the garden.
