We Lithops, often called "living stones," hail from the harsh, arid landscapes of southern Africa, primarily in Namibia and South Africa. Our existence is a masterclass in survival. We thrive in environments with intense sunlight, minimal rainfall, extremely well-draining soil, and significant daily temperature fluctuations. Our entire being is engineered for this: our low, ground-hugging profile minimizes sun exposure, and our fused leaf pairs, which contain water-storing tissue, allow us to endure prolonged droughts. This is the baseline of our hardiness; to understand if we can live outdoors with you, you must first understand our home.
You humans use USDA Plant Hardiness Zone Maps to gauge what can survive your winters. This system is based on the average annual extreme minimum temperature. For us Lithops, this metric is only half the story, and frankly, the more dangerous half is your summer, not your winter. We cannot tolerate sustained freezing temperatures. Our cells are full of water, and a hard freeze will cause this water to crystallize, rupturing our cells and killing us. Therefore, we are only truly perennial outdoors in zones where winter temperatures reliably stay above freezing, such as parts of zones 10a (30-35°F / -1.1 to 1.7°C) and, more securely, 10b and 11.
Assuming you live in a suitably warm zone, the decision to plant us outdoors is still fraught with peril. Our greatest enemies in a typical US landscape are not just winter cold, but:
Excessive Rain & Humidity: Our roots are supremely adapted to quick sips of water followed by long, dry periods. Consistently damp soil, especially from summer thunderstorms or winter rains, will lead to rapid root rot and our swift demise. We must have absolutely perfect drainage.
Poor Drainage: Even in a dry climate, being planted in heavy, clay-rich soil that retains water is a death sentence.
Insufficient Sunlight: We require a tremendous amount of bright, direct light to maintain our compact form and function properly. A shaded garden spot will cause us to etiolate—become stretched and weak—and eventually perish.
So, can we survive outdoors in the US? The answer is a highly conditional yes, but only under very specific, meticulously controlled circumstances. We are not landscaping plants for a typical flower bed. Success is most likely in arid parts of the Southwest US, such as Arizona or Southern California, that mirror our native habitat. Even there, we are best suited for a specialized garden feature: a raised rockery or an alpine trough garden. This setup must be engineered with a very gritty, mostly inorganic soil mix (80-90% gravel, pumice, or coarse sand) to ensure instantaneous drainage. It must also be positioned for maximum possible sun exposure and, crucially, must be protected from overhead rain, perhaps by an overhang or a temporary cover during your wet season.
For most of our human caregivers across the US, the safest way to grant us an outdoor life is in a container. A pot allows you to create our perfect gritty soil mix and provides ultimate control over our environment. We can enjoy the fresh air and optimal sunlight on a patio during the warm, dry growing seasons (spring and fall). When the threats arrive—be it the relentless summer rains of the Southeast, the freezing winters of the North, or a surprise hailstorm—you can simply move our pot to a sheltered location. This mobile existence gives us the best chance to thrive while mitigating the unpredictable elements of the American outdoors.
