Desert Rose (Adenium obesum): Introduction, Origin, Classification, Description, Propagation
Introduction
The Adenium genus is a member of the Apocynaceae family, which also includes numerous tropical ornamental species like Catharanthus species, Beaumontia species, Carissa species, Allamanda species, Mandevilla species, Nerium species, and Plumeria species (COLOMBO et al., 2015). Adenium obesum, originally known as Nerium obesum, is the only species reported for this genus (fat oleander).
Adeniums are succulent plants having herbaceous, shrubby, and arboreal branches and roots. Many species are caudiciforms, also known as paquicaules, which have swelling stems and/or roots that serve as the main organs for water storage. The blooms contain five different-colored sepals and petals attached to a floral tube. The inside surface of the tube may include five or fifteen red lines known as nectar guides. The anthers’ slits face the interior of the cone-shaped five stamens, which have five stamens. The real anthers appear to be the anther tails that extend from the cone apex. Just below the anthers, in the cone-shaped structure the stigma is concealed (DIMMITT et al., 2009).
After pollination, the fruits, which are referred to as follicles, are developed in pairs. When fully grown, they split open transversely to release the seeds (DIMMITT et al., 2009). However, not all plants generate seeds when grown because pollination frequently fails because of male or female sterility.
Origin
A. obesum can be found in sub-Saharan Africa, from Sudan into Kenya, west to Senegal, and south to Natal and Swaziland. The Arabian peninsula’s southwest portion has a couple of them (Yemen).
Classification
Kingdom: Plantae
Order: Gentianales
Family: Apocynaceae
Genus: Adenium
Species: A. obesum
Scientific Name: Adenium obesum
Common Name(s): Desert rose, Mock azalea, impala lily, and Sabi star
Description
Adeniums are succulent pachycaul (with thicker stems) shrubs or trees that have a distinctive swollen base (caudex), much of which can be subterranean. The caudex can vary in shape above ground from virtually globose to conical before it narrows and splits into multiple branches with erratic spacing. The plants’ look and flower display vary in their natural location, but they typically have a moderate growth rate and a lengthy lifespan, lasting for hundreds of years. Often, a distinct caudex is no longer discernible in cultivated, mature specimens. With terminal, spirally organized, tiny, glossy green leaves, the branches are smooth, greyish green to brown. Winters are dry and sufficiently cold in places where they are native, causing a period of hibernation and the corresponding loss of leaves. In South Florida, plants frequently lose some of their leaves in the winter, especially during periods of extended dryness and coolness. They never truly go into hibernation, though.
Flowers
Flowers are salverform (tubular with flared lips), as do many Apocynaceae species (such as oleander and frangipani), and they come in a variety of colours, from deep purple red to white. Flowers from several varieties come in a wide range of colour combinations, shapes, and sizes (up to 3 inches). A couple of them also have a pleasing scent as an added advantage. Most of the year, tiny, terminal flower clusters, or corymbs, are produced, however, flowering is more restricted in some varieties. From late winter to early summer, when the weather is drier, the desert rose is most showy in Florida and can be almost completely covered in blossoms.
Fruit
The fruit, which is a follicle, splits down the middle to produce seeds with pappuses (tufts of hair that help seeds spread) on each end. Because male or female sterile plants are commonly used for agriculture, pollination frequently fails, making seed production unreliable.
Characteristics
1. It is a succulent evergreen or drought-deciduous shrub (which can also lose its leaves during cold spells, or according to the subspecies or cultivar).
2. It can reach a height of 0.12 to 5 metres (0.39 to 16.40 feet), and its stems are pachycaul (excessively large) (a rootstock that protrudes from the soil).
3. The leaves are simple, whole, leathery in texture, and spirally organized. They measure 5–15 cm (2.0–5.9 in) long and 1–8 cm (0.39–3.15 in) wide.
4. The flowers are tubular, 2-5 cm (0.79-1.97 in) long, with an outer section 4-6 cm (1.6-2.4 in) diameter and five petals, resembling those of other related genera like Plumeria and Nerium. The flowers usually have a pale throat flush and are red or pink.
5. Some of the common names for a plant include desert rose, fake azalea, impala lily, and Sabi star.
6. Adeniums are quickly gaining popularity as houseplants all over the world because of their unusual shape, stunning blossoms in hues ranging from deep red to pure white, and long-standing cultivation by fans of succulent plants.
Propagation
For the majority of gardeners, cuttings are the easiest technique of propagation. Tip cuttings of about 5 inches, preferably leafless, are soaked in fungicide/rooting hormone and placed in a moistened 75/25 mixture of Perlite and Canadian peat. Misting and bottom heat might hasten the rooting process. Check cuttings for fresh leaves, and eliminate any that show withering symptoms. For valuable hybrid types, cleft grafting is preferred since it is said to be more reliable but does require a little more skill. The size of the rootstock and scion should match, and the rootstock should be clipped about three inches above the caudex. To create a wedge, create cuts of 34 inches on either side of the scion’s severed end. The trimmed scion is then put into a vertical 34-inch incision made across the cut surface of the rootstock so that the cambial layers of the cutting and rootstock are in touch. Wrap the junction in grafting tape. A limited amount of air layering has been utilized to grow desert rose; if successful, roots will form in 6–8 weeks. Success is more probable in hot, muggy conditions.
Pollination problems make seed propagation unreliable. To assure the development of healthy seeds, hand pollination with male/female suitable plants is required for those creating new types. If the fresh, viable seed is available, it will germinate quickly and at a high rate. Remove the pappus, sprinkle the seeds with fungicide, and then plant them in a sterile, sandy, freely draining soil mixture. At 85 EF, germination takes place within a week, and after a month, seedlings should have at least six true leaves and be prepared for transplanting. Plants produced from seeds frequently bloom in the same year and should get regular fertilizer applications in addition to any necessary irrigation.
Growing in Containers
Any container that allows for enough drainage can be used to produce desert roses. Ceramic pots that are unglazed are best since they let the soil air dry in between waterings. If a clay pot is used, it had to be wide enough (i.e., dish-shaped) to accommodate the caudex’s expansion, or the pot risked cracking. Until the plant reaches maturity, a free-draining potting mix should be used with frequent doses of liquid fertilizer (half strength 20/20/20). In regions where Winter temperatures are too low for the plant to be grown safely outside, think about using a container. Growing desert roses in a portable container offer the benefit of allowing the plant to be covered during rainy seasons, which is advantageous in regions with cool, wet winters.
Frequently Asked Questions
Question: Is Adenium Obesum poisonous to humans?
Ans: Yes
Question: Is Adenium an indoor plant?
Ans: Yes
Question: Where should a Desert rose be placed in a room?
Ans: A Desert rose should be placed in the window with the maximum sunlight, where it will receive direct light for at least six hours each day.
Question: How often should a Desert rose be watered?
Ans: Water them twice or three times a week.
Question: How long does a Desert rose plant live?
Ans: The desert rose can live for up to 500 years.
Question: Is Adenium toxic to dogs?
Ans: Yes
Question: How big does a Desert rose plant get?
Ans: It can reach a height of 0.12 to 5 metres (0.39 to 16.40 feet),
Question: Is Adenium perennial or annual?
Ans: perennial
Question: What does a Desert rose flower symbolize?
Ans: wealth to the owner