Numerous species of ice plant are found in at least nine different genera. These low-growing succulent perennials and a few annuals were once all lumped under the genus Mesembryanthemum.
Today this genus only contains annuals that have naturalized along the California coast. Other genera that contain "ice plant" that you may recognize are: Aptenia; Carpobrotus; Cephalophyllum; Delosperma; Drosanthemum; Lampranthhus; Malephora; Dorotheanthus. All grow best in well drained soil and are not traffic tolerant. Some are quite invasive.
Aptenia cordifolium is the well know Red Apple used on slopes in the San Diego area. To look its best, summer irrigation is advised. It has replaced the following in popularity as a ground cover. Carpobrotus chilensis (photo above) and edulis are the familiar succulents you see invading canyons and taking over freeway slopes. Originally thought to hold slopes, it is now understood that it creates just the opposite condition due to its weight. Additionally, the thick dry undermat is instant fuel for wild fires. Attractive as its flowers are, this is one to avoid. It is so insidious, it has been placed on the "Ten Most Wanted" list of invasive plants harmful to natural habitat by the California Native Plant Society.
Cephalophyllum or Red Spike Iceplant has bright red blossoms that honey bees adore. Watering should be reduced in the summer. Delosperma is a genus of 7 species of generally low height (1/2 to 4") ground covers. These require regular water in the summer. Lampranthus (photo above left) is a genus of 6 species and is characterized by their bright flowers ranging from bright yellow through pink to red and purple. This should be cut back to get good new growth.
Drosanthemum is the genus of iceplant whose foliage appears to glisten with ice crystals. D. floribundum (photo above) or hispidum forms a blanket of pale pink or lavender flowers over its surface and is very attractive to bees. It is the BEST iceplant for erosion control and can tolerate poor soils. Malephora (photo above right) is another genus that is called ice plant. This genus (2 species) is highly resistant to heat, wind and fire. Flowers are orange to yellow.
Dorotheanthus is an annual genus sometimes called Livingstone Daisy. It flowers in a variety of colors on the same plant and tolerates poor soils. Armed with your new knowledge of "ice plant" it is wise to shop carefully when selecting a cover for rock gardens, borders or slopes.
Meredith French has been a professional photographer for 30 years. She was accepted into Master Gardeners in 2005 and does public speaking for them. She also writes on a variety of garden topics and is a regular contributor to California Garden. She often features the insects and other wildlife of her own certified habitat garden. Many of these images are for sale at meredithfrenchphoto.com.