Adenium obesum is a popular plant for home-growers because of its unusual trunk. Also known as the "Desert Rose," the adenium obesum originates from east Africa and northern Arabia. It is a succulent in the Apocynaceae family, with glossy leaves and colourful flowers. The flowers range from a white and pink mix to a crimson and red mix.
Adenium obesum grows to nine feet tall. The trunk is a basal caudex--a thick, highly unusual formation at the base of the plant. It is pale grey and will form unique shapes. The basal caudex can grow as a simple cone shape, or it can grow with the twists and turns and swellings that is desired by growers. To promote unusual basal caudex formation, replant the adenium obesum periodically, leaving a little more of the trunk exposed each time.
Adenium obesum should be planted in very well-draining soil, preferably a cactus mix. It can be either planted in a container or in the ground. It requires full sun and is very heat-tolerant. Adenium obesum will go dormant in cooler temperatures.
It is best to water in the morning, allowing the plant to absorb water throughout the day. Like cactus, adenium obesum needs the soil to dry out a little between waterings. Water just until the soil is moist, but not soggy. Over-watering can damage the caudex. Water the soil only and do not wet the leaves or the caudex. Using a fertiliser will help the caudex swell and form interesting shapes. Do not use a fertiliser that is high in nitrogen. Do not fertilise when the soil is dry, as this can burn the roots and caudex. Always use plain water first, then fertilise the damp soil. Adenium obesum blooms in the spring and again in the fall.
Adenium obesum can be propagated by seed or cuttings. Seeds can be scattered over the soil and will germinate easily. The seedlings grow well without additional help. To propagate by cuttings, cut off an end shoot and then let it dry for a day or two. Insert the shoot into a pot of moist planting mix, and then set the pot on a heating pad or other source of low heat until new growth appears.
All parts of the adenium obesum are toxic to humans and animals. This includes the flowers and the sap. Be careful to avoid the sap when cutting shoots.