Size and shape vary among the species within the Lampranthus genus, but most of the commonly grown ice plant varieties reach up to 2 feet tall and have a spreading habit. Ice plants thrive in sunlight and poor soil, and they make a wonderful alpine or rock garden plant. They also can be tucked into stone walls. Their spreading habit means they quickly fill a container and spill over, so they are nice in hanging baskets and free-standing pots.
You can grow ice plants by division, cuttings, and seeds. If you’re dividing established plants, do so in the spring. Cuttings can be taken and rooted at any point during the growing season, though they are best planted outdoors as early in the season as possible. And if you’re growing by seeds, simply scatter them over the soil in the spring. But don’t cover them, as they need light to germinate.
All varieties of ice plants grow and bloom best in full sun. Their flowers tend to open to their fullest extent under sunny conditions. And plenty of sunshine helps prevent the plant from becoming leggy.
The key to growing ice plants is to provide sandy (or gravelly), well-draining soil with a neutral soil pH. This plant is fine in soil that’s low on nutrients. But avoid clay soil and any location where the plant will sit in water. Ice plants will rot and die if they’re left in wet soil for a prolonged period.
As succulents, established ice plants are extremely tolerant of drought. However, they do prefer regular watering roughly once a week, especially during the hottest part of summer. If you’re growing your ice plants in a container, you’ll likely have to water them slightly more often than those planted in the ground. Allow the soil to dry out between waterings in the winter when ice plants are somewhat dormant. Water seedlings regularly to keep the soil moist but not wet.
Temperature and Humidity
Despite their name, ice plants are no fans of icy, cold weather. Hardiness varies with the species and variety, but most plants from this genus prefer only warm climates. While some species can tolerate a light frost, gardeners in cold climates do best growing them as annuals or houseplants. Moreover, high humidity and damp conditions can cause ice plants to rot. They thrive in dry climates.
Fertilizer usually isn’t necessary for in-ground ice plants, as they grow well in poor soil. But if blooming is sparse, feeding might be a solution. Likewise, plants grown in containers deplete their nutrients more rapidly and can benefit from a balanced fertilizer, applied following label instructions.