Issue: April 9, 2005
I have an ice plant and I like it very much, but I wonder why it is called "ice plant"? It doesn't grow in the winter; in fact, it dies back somewhat during that time.Answer:
Ice plants are often used in southwestern landscapes because they are very interesting, drought-tolerant plants that produce beautiful flowers all summer. They are called ice plant because they have bladder-like hairs on the leaf surface that reflect and refract light in a manner to make it appear that they sparkle like ice crystals.
Since the name ice plant is a "common name" rather that a scientific name, it is applied to many different plants that may appear to sparkle. Therefore, there are many different plants called ice plant. The one we grow most often in New Mexico (Delosperma cooperi) is often just called Delosperma by some horticultural authors to distinguish it from the others. Another used in New Mexico is Delosperma nubigenum which is the hardiest of the succulent plants called ice plant. It is reported to have survived -25 degrees F., while the Delosperma cooperi may perhaps survive temperatures as low as 0 degrees F. In southern New Mexico's warmer winter temperatures, there is an even larger array of these very striking plants that may survive the winters.
It has been my observation that Delosperma grown on the south side of a house or wall that creates a warm environment during winter may experience significant winter die back. This may be due to increased drying of plants and soil in these locations. Even though this is a succulent plant that is very drought tolerant, it may benefit from occasional winter irrigation.
A little more information about this interesting group of succulent plants is that some of the relatives of Delosperma (Carpobrotus, also called ice plant or Hottentot's fig) are banned in some states because of their invasive nature. Delosperma is not banned.
Other interesting relatives of Delosperma are the livings stones (Lithops and similar plants) and a common hanging basket plant called Hearts and Flowers (Aptenia cordifolia). All of these plants have interesting, often colorful flowers with many petals. However, other than the Delosperma, the others are not hardy enough for outdoor use in most of New Mexico.
Send gardening questions to Southwest Yard and Garden, Attn: Dr. Marisa Thompson at firstname.lastname@example.org or at https://www.facebook.com/DesertBloomsNM/. Please include your county Extension Agent (aces.nmsu.edu/county) and your county of residence with your question!
For more gardening information, visit the NMSU Extension Horticulture page at desertblooms.nmsu.edu.
Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, office: 505-865-7340, ext. 113.