Desert Rose Adenium

Adenium is a genus of succulents that are a part of the Apocynaceae family, otherwise known as Dogbane because some members provided poisons used to kill dogs. Plants can reach 15' in their native habitat but seldom grow that tall in a garden. The members of this genus are unusual in that they have a caudex (soft swollen stem) as a trunk. The caudex acts as a water storage organ and helps the succulents to survive long periods of drought. Some of these caudices can be 20 to 30 inches wide. As these caudices can develop fantastic shapes, the plants are popular as specimen and bonsai plants.

The members of the genus are very attractive plants with their strange, twisted caudices, branches with crowns of shiny, green leaves at their ends, and 2” wide, tubular flowers in white, pink, red and variegated forms. The flowers are reminiscent of those on the Mandevilla vine.

As they are native to the dry areas in sub-Saharan Africa and Saudi Arabia, these are ideal plants for drought tolerant gardens as well as very sunny, hot spots. Remember to provide sandy or gravelly soil to mimic their desert origins. But be careful where you place them. The leaves and stems carry a latex inside which at a minimum can cause rashes but, if too much is ingested, can be toxic.

As a succulent from dry tropical zones, they are winter hardy in zones 10-11. In other areas they must be protected from winter rains and cold. Once temperatures drop to 55°F at night, bring them inside to a well lit place and reduce watering. The plants may drop their leaves and go dormant. If that happens reduce watering or stop it altogether until the leaves begin to grow. There is a species, Adenium swazicum, which comes from mountainous areas and is more tolerant of cool weather.

VIDEO Created by Laura Barth for "Houseplants, Succulents, and Cacti", a plant identification course offered in partnership with Longwood Gardens.