From our perspective, the question of winter survival is not a simple yes or no. It is written in our very DNA. We lilies are a diverse family, with species originating from the cool woodlands of North America, the mountainous regions of Asia, and the temperate zones of Europe. This genetic heritage dictates our fundamental cold tolerance. For instance, my relatives like the Asiatic and Oriental hybrids possess a certain level of hardiness, but we are not all created equal. A tough Martagon lily (Lilium martagon) can withstand deep freezes that would be fatal to a more tender, but beautiful, Easter lily (Lilium longiflorum). So, the first answer lies in knowing exactly which type of lily you are asking about.
Our survival strategy is centered on our bulbs, which are our energy storage units. As daylight shortens and temperatures drop, we receive the signal to prepare for dormancy. Our above-ground foliage yellows and dies back—a process you should not interrupt! This is us redirecting all our energy downward into the bulb. Once dormant, we rely on the surrounding soil to act as a protective blanket. The soil's consistent temperature, especially beneath a layer of snow, is far more stable than the frigid air above. A thick layer of mulch applied after the ground first freezes is like being tucked in with an extra duvet; it prevents the freeze-thaw cycles that can heave our bulbs out of the ground and damage our delicate roots.
Your human "USDA Plant Hardiness Zone Map" is an excellent translator for our needs. It defines the average annual extreme minimum winter temperature for a given area. This map allows you to cross-reference your local climate with our genetic requirements. Most common garden lilies, like Asiatics, are comfortable in zones 4 through 8. This means our bulbs can tolerate winter lows down to -30°F (-34°C) when properly planted and mulched. Oriental lilies prefer slightly milder winters, typically thriving in zones 5 through 9. If you live in a zone colder than our rating, our survival becomes exceedingly difficult without significant protection, and we may perish.
Your actions in the fall directly impact our ability to endure. Planting our bulbs at the correct depth—about three times the height of the bulb—is paramount. This places us deep enough to be below the most drastic temperature fluctuations at the soil surface. Furthermore, the soil itself must be our ally. We demand well-draining soil. If our bulbs sit in cold, soggy earth throughout winter, we will almost certainly rot. Waterlogged conditions are a far greater threat to us than the cold itself. Ensuring the planting site does not collect standing water is a critical step for our long-term health.
For our kin living in containers, the winter is a particularly dangerous time. A pot exposes our entire root system to the ambient air temperature, which can freeze solid and rupture our cells. We cannot survive this. If you have potted lilies, they must be moved to an unheated garage, shed, or cool basement where the temperature remains consistently cold but above freezing (ideally between 35-45°F or 2-7°C). This allows us to remain dormant without being killed. Similarly, tender lily varieties not suited to your zone must be lifted from the ground in the fall and stored in a cool, dry medium like peat moss until spring.
