Planting and Care of Socotra Roses (Adenium socotranum)

 

General Cultural Requirements

Socotra desert roses are not difficult to grow and generally require the same care as the other more common Adenium species that are widely cultivated. There are two exceptions to this: the plants require a long period of winter dormancy and are very slow growing.

 

Receiving Your Plants

Desert roses should be unpacked upon receipt and stored in a well-ventilated area out of the direct sun until they are planted. Prolonged holding times in packaging materials may promote fungus growth and rot. These plants are usually hardy in shipment provided that they are not subject to cold temperatures. If the plants are not dormant at the time of shipping you may expect the leaves to be damaged in shipment and lost after receipt of the plants. They should grow back during the next growing season.

 

Dormancy

In Hawaii Socotra roses usually begin to loose their leaves and enter into dormancy in early spring.   The leaves reappear at the onset of their growing season beginning in early summer. Growth and dormancy patterns and the amount of leaf loss often vary significantly even between plants from the same seed lot and grown under similar conditions. Here in Hawaii we have some plants that have been leafless and dormant for more than a year, and others that have minimal leaf loss and some growth during the winter months.  The plants may bloom during dormancy.

Attempts to break dormancy and force growth by increasing fertilization and watering may promote rot and result in loss of the plant. The plants also need to have warm soil at all times. When leaves are present they should be kept in full sun.

 

Planting Media and Containers

Well-drained potting soil such as the commercially available mixtures used to grow cactus are adequate but should contain 20-30% added dolomite, limestone, oyster shell or coral rock to provide additional calcium and magnesium, increase the soil pH and simulate Socotra soil conditions.

In their natural environment on Socotra island large plants can be found growing in cracks in rocks and other highly confined spaces. In cultivation they often form minimal roots and can be maintained in shallow, small volume containers for long periods of time.  However, plants grown in larger pots with deeper soil may grow faster.  For plants grown outdoors in areas with high rainfall it may be advisable to use unglazed clay pots rather than plastic pots.

 

Watering

The plants are highly resistant to drought conditions but benefit from consistent soil moisture levels when they are actively growing. Water indoor plants only when they have leaves and allow the soil to dry out thoroughly before watering again. Minimize or avoid watering when the plants are dormant or the soil temperatures are cool.

In Hawaii we have found these plants to be remarkably tolerant of prolonged periods of rainfall if maintained in rapidly draining soil media.

 

Fertilization

The plants are not fastidious regarding fertilizer applications. They should be fertilized monthly when they are actively growing with a complete fertilizer such as Miracle Gro®. More frequent applications at lower concentrations are preferred. Avoid fertilization when the plants are dormant. Slow release fertilizers such as Osmocote® can also be used and may be supplemented with additional rapid release fertilizers during the short season of active growth.

 

Diseases

Socotra desert roses have few diseases except that they are susceptible to soft rot if maintained in wet, cold soil conditions for prolonged periods of time.

 

Pests

The most common pests of Socotra desert roses are mealy bugs, aphids, scale insects and spider mites and these are more likely to affect plants kept indoors. Insecticidal soap, sulfur emulsions and neem oil based insecticides are effective in controlling these pests.

The use of granular, well-drained soil media as recommended for these plants may allow mealy bugs to access and infest the roots. These infestations may be difficult to detect and if severe, pronged and untreated they may stunt or kill the plant. The use of systemic insecticides such as imidacloprid applied as a soil drench is the only treatment we have found to effectively control mealy bugs on roots. The addition of diatomaceous earth as a soil amendment may also be useful in preventing and controlling infestations, and provides an alternative to imidacloprid that is acceptable for organic culture, and my benefit the plants by increasing the availability of silica.

 

Growing Socotra Desert Roses in Hawaii

These plants thrive in containers outdoors in full sun in at lower, warmer elevations. However, they should not be planted directly in the ground as they may do poorly in highly pervious volcanic soils that tend to dry out quickly and may trigger dormancy.