The desert rose (Adenium obesum) is a striking plant with succulent stems and deep red flowers. The plant is deciduous in cooler winters, but it can be kept in leaf provided there is sufficient warmth and light water. Every part of these plants commands interest, from the dramatically swollen stems on older plants to the bright flowers to the tight clusters of narrow, green leaves. However, there is an important consideration when growing this plant, particularly in the house: its sap is poisonous and should never come into contact with children or pets.
If you get sap on yourself while handling the plant, wash your hands immediately.
Light: Full sun. Perfect for a sunny window.
Water: Water during the summer and spring. Reduce water in the winter, but keep hydrated enough to retain its leaves.
Temperature: Keep at least 50 F at all times; if you keep temperatures of 60 F or higher during the winter, the plant may retain its leaves.
Soil: A well-drained succulent mix, with an ideal pH around 6.0 (slightly acidic).
Fertilizer: Fertilize during spring and summer with controlled-release fertilizer or liquid fertilizer according to label directions.
Propagation is typically by seed. If your plant develops a seed pod, plant the seeds as soon as possible after the pod ripens, to maximize the chance of germination. The fresher the seeds the better. If you don't have a mature plant for harvesting seeds, ask your seed supplier about freshness before buying.
Some gardeners use a heat source to keep the containers at 80-85 F; otherwise, they should be kept as close as possible to that temperature range. Once the seeds germinate, the plants should be ready for moving to a pot in about a month.
The desert rose can be propagated from branch cuttings, but the plants often fail to develop the characteristic (and highly desired) bulbous stem.
Repot as needed, preferably during the warm season. To repot a succulent, make sure the soil is dry before repotting, then gently remove the plant from the pot. Knock away the old soil from the roots, making sure to remove any rotted or dead roots in the process. Treat any cuts with a fungicide and antibacterial solution. Place the plant in its new pot and backfill with potting soil, spreading the roots out as you repot. Leave the plant dry for a week or so, then begin to water lightly to reduce the risk of root rot.
Adenium belongs to the genera Apocynaceae, which is native to Africa, the Middle East and Madagascar. The desert rose (A. obesum) is the only Adenium found in wide cultivation, although it has been hybridized extensively to obtain different flower colors, including orange, white, striped and the traditional red.
These are not difficult plants to grow well, provided they get enough sunlight and warmth. Like all succulents, they cannot tolerate sitting in water, and if you err, do it on the side of too little water. Use a specialized soil mix designed for succulents and cacti.