Purslane (Portulaca oleracea) is a common, resilient plant found globally. This succulent annual, with fleshy stems and leaves, thrives in various environments. It often appears as a ground cover, producing small, colorful flowers. Though frequently considered a weed, its robust nature makes it a notable botanical specimen.
Purslane’s Natural Hardiness
Purslane naturally prefers warm conditions, flourishing during the hottest parts of the year as a warm-season annual that completes its life cycle in one season. This plant self-seeds readily, reappearing year after year in suitable environments. Its inherent toughness contributes to its widespread distribution and ability to grow in diverse settings, including disturbed soils and cracks in pavement. This adaptability stems from its succulent nature, enabling it to store water in its leaves and stems, which aids in drought tolerance.
Understanding Temperature Thresholds
Purslane cannot tolerate frost. When temperatures drop to freezing (32°F or 0°C) and below, water within the plant’s cells freezes and expands, causing cell walls to rupture and leading to tissue damage, typically resulting in the plant dying. Visible signs of cold damage include wilting, drooping leaves, and discoloration, often turning black. Even a light frost can cause significant damage.
The plant’s optimal growing temperature range is generally between 65°F and 80°F (18°C and 27°C). Purslane can begin to show signs of stress if temperatures fall below 40°F (5°C). While it can tolerate brief dips, prolonged exposure to temperatures below freezing will typically kill the plant.
Protecting Purslane from Cold
Protecting purslane from unexpected cold snaps can extend its growing season. When a light frost is predicted, covering plants with frost cloths, blankets, or cloches provides a temporary shield against the cold, trapping residual ground heat. Place these covers in the late afternoon or early evening, before temperatures fall. Remove covers once temperatures rise the following morning to prevent overheating and allow for proper air circulation and light exposure. For container-grown purslane, moving pots to a more sheltered location can offer additional protection from chilling winds.
Overwintering Purslane
Overwintering purslane, particularly in colder climates where it typically perishes outdoors, requires specific strategies. Bringing potted purslane indoors before the first hard frost is a common method for extending its life. Indoor conditions should provide adequate light, ideally near a sunny window, and reduced watering, as the plant’s growth slows during winter.
For purslane growing directly in the ground, successful overwintering as a perennial is generally limited to very mild zones, such as USDA Zones 10 or 11. Mulching in-ground plants can offer some minor insulation, but it is typically insufficient to protect purslane from harsh winter conditions in colder climates, as the plant is inherently tender and cannot withstand freezing temperatures for prolonged periods. An alternative to overwintering entire plants is collecting seeds for replanting the following spring, or taking cuttings to propagate new plants indoors.