The ZZ plant (Zamioculcas zamiifolia) stands out as a highly resilient and popular houseplant, favored for its striking appearance and low-maintenance nature. Understanding where this plant can naturally thrive, particularly concerning its temperature needs, is important for successful cultivation. This article clarifies the ZZ plant’s hardiness zones and its specific temperature tolerances, providing guidance for both outdoor and indoor growing environments.
Understanding Plant Hardiness Zones
The USDA Plant Hardiness Zone Map is a standardized tool that helps gardeners identify which perennial plants are most likely to survive winter temperatures in a specific location. This map divides North America into zones based on the average annual extreme minimum winter temperature. Each zone represents a 10-degree Fahrenheit difference, with subzones (a and b) further refining this by 5-degree increments.
The map informs gardeners about the coldest temperatures a plant can endure outdoors and survive the winter, serving as a general guide for perennial survival in a given climate. While helpful, it does not account for other factors like soil type, rainfall, or summer temperatures.
ZZ Plant Hardiness
The ZZ plant is a tropical perennial originating from the arid regions of eastern Africa, including Kenya and South Africa. For outdoor cultivation, the ZZ plant is suited for USDA Plant Hardiness Zones 10 through 12. Some sources also indicate Zones 9 and 10.
These zones are characterized by mild winters where temperatures rarely, if ever, drop below freezing. Such conditions allow the ZZ plant to be grown year-round in the landscape, benefiting from the consistent warmth and absence of frost. For those outside these warm regions, the ZZ plant is almost exclusively cultivated indoors due to its inability to withstand cold temperatures and frost.
ZZ Plant Temperature Tolerance
ZZ plants prefer a warm and stable environment, ideally maintaining temperatures between 65°F and 75°F (18°C to 24°C) for optimal growth. Some sources suggest a slightly broader range, from 60°F to 85°F (15°C to 29°C), still emphasizing warmth and consistency. Temperatures below 50°F (10°C) can cause active growth to slow down and may lead to injury or discoloration of the plant.
The plant is particularly sensitive to sudden temperature drops and cold drafts. Exposure to temperatures below 45°F (7°C) can cause significant damage. Frost, below 32°F (0°C), is lethal to ZZ plants. Signs of cold stress include wilting, leaf discoloration, and general tissue damage.
Outdoor vs. Indoor Cultivation Considerations
For gardeners residing in USDA Zones 10-12, ZZ plants can be successfully grown outdoors year-round. When planting outside, it is important to choose a location that offers strong, filtered light or partial to deep shade, as direct, intense sun can be too harsh. Ensure the soil is well-draining to prevent waterlogging, which can be detrimental to the plant’s rhizomes.
For most growers in cooler climates, ZZ plants thrive indoors where their preferred temperature range can be maintained. Place them in areas away from cold windows, exterior doors, or heating and air conditioning vents, which can create temperature fluctuations and drafts. Maintaining a consistent indoor temperature ensures the plant remains healthy. While ZZ plants can tolerate dry indoor air, stable conditions contribute to their overall well-being.