Thursday, October 9, 2008

desert rose

I have interest in growing plants and flowers. However, I will be the first to admit that I do not have “green fingers”. My brother’s girlfriend has “green fingers” and whatever plants she grows will blossom.

As such, I have “killed” many plants and flowers over the course of several years. For example, I have bought pots of baby rose several times but each time, I have not been successful in keeping the roses alive.

I have since realised that I am perhaps more suited to cultivate and grow more hardy plants and flowers such as orchids. In fact, I have successfully cultivated my own orchid plant using plant cuttings from an existing orchid plant that I bought from the nursery.

Da and I live in a small apartment. However, we are blessed to have a balcony next to our living room and a balcony next to the master bedroom in our apartment. Whilst people will be eager to place outdoor tables and chairs in their balconies so that they can sit in the balcony and relax, in our case, our balcony is full of plants!

As the balcony next to the master bedroom is very small, there are only 2 pots of orchids in the balcony. In one of the pots is an orchid plant cutting that I cut from another orchid plant. I was so excited the other day to see flowers growing from that plant cutting!

The balcony next to the living room is my little garden. In that balcony, we have:-
(a) 2 pots of bougainvillea
(b) 3 pots of orchid (one of which totally comprises plant cuttings - this is my pride and joy because I have managed to cultivate and grow my own orchids!)
(c) 4 pots of dessert rose (three of which are cultivated from plant cuttings - I have tried to cultivate my own desert rose numerous times, without success. These three pots are my latest efforts - I hope that I am successful this time around)
(d) 3 pots of sweet basil (two of which are cultivated from basil seeds).

Every now and then, I will drag Da to a nursery. The dear boy will patiently wait for me to select my plants and flowers and then carry the pots to the car to bring them home.

A few years ago. we were at a nursery in December when we came across a flowering plant. The base of the plant was very fat and there were lovely red flowers that looked a bit like hibiscus flowers. The nursery owner informed me that this plant is known as “desert rose” and it is popular with Chinese families during Chinese New Year. He also explained that the thicker the base, the more expensive the desert rose. We decided to buy a small pot (which cost us around S$60).

Since then, my pot of desert rose has been flowering constantly. It brings me great joy when I see the beautiful red flowers.

I have been trying to cultivate my own desert rose. I asked my aunt (who cultivates her own desert rose in Malaysia) and she said that all I need to do is to grow the plant from a plant cutting. Armed with this advice, I cut off a part of the branch of my desert rose and planted it in a pot of soil. Alas, after some time, the branch became hollow inside and the plant died. I repeated this attempt several times, all without success.

My colleague (whom I just found out cultivates her own desert rose) has advised me that the soil should not be too wet. She also said to use a new pot of soil each time I cultivate a new plant. As such, I am trying again.

In the meantime, I think that it would help to have more knowledge about desert rose. I decided to check the internet for tips on how to cultivate desert rose.

Adenium (commonly known as “desert rose”) is a flowering plant containing a single species, “Adenium obesum” also known as “Sabi Star” or “Kudu”. It is native to tropical and subtropical eastern and southern Africa and Arabia.

Flowers are best during the spring and fall months but flowering can occur any month of the year. The older the plant, the better care one tends to give to it, resulting in more flowers.

Desert rose, mock azalea, impala lily, and Sabi star are just some of the common names of a plant coming to a mega-store near you. Long grown by succulent plant enthusiasts because of its bizarre shape, beautiful flowers in colors from deep red to pure white, and its tolerance of occasional neglect, adeniums are rapidly becoming popular horticultural subjects and houseplants worldwide.

Flowers can be seen in shades of pink, rose white or red in colour.

Adeniums like a neutral to hard water. Acidic water tends to sour the soil too fast and may cause root rot. Water plants preferably in the early morning, and allow them to drink up throughout the day. Watering can be done daily to every few days. Never allow your plants to sit in a saucer of water, neither allow them to dry out too often - this causes adeniums to go into early dormancy.

Growing to a height of about 4-5 ft, this succulent plant is a member of the same family as Plumeria. Its swollen, often twisted trunk is pale gray. The leaves are glossy and club-shaped, and the flowers, which appear almost continuously, are trumpet-shaped, and range from white and bright pink to crimson red. It exudes a highly toxic sap which in some places is used as a poison for arrows. Adenium is not generally grown in moist tropical gardens but is often seen as a decorative pot plant; it may also be used in rock gardens. It needs full sun and a well-drained potting mixture. Exotic multi-color varieties can be grafted on the same plant.

Adeniums have many spectacular hybrids. The basic culture is very similar to orchids. A small pot with excellent drainage is a must. Adeniums do not like both over-watering or drying-out.

Every time you re-pot the plant, you should lift the plant a bit so the upper parts of roots will be a little exposed. The plant will form more roots that will go down.

The name “rose” in “desert rose” is a misnomer. For one thing, it has no thorns. But beyond that, it is totally unrelated to the rose family and does not even look like one. The desert rose is scientifically known as Adenium obesum, or the fat adenium, referring to its grossly thickened trunk. It is in the Apocynaceae, or periwinkle family, which, besides the common garden periwinkle, includes oleander (frequently used as floriferous landscape shrubs in mild climates), the spiny Madagascar palm (which is not a palm at all), and the fragrant frangipani, or Plumeria which is grown worldwide in tropical climates. Desert Rose is a succulent bush with thick fleshy branches. The "obesum" name refers to the large fat base of the plant.

Like most all succulents, adeniums, especially when dormant, are susceptible to root rot (which can rapidly kill the entire plant) caused by prolonged, overly wet soils. Therefore, they should be potted in a well-drained soil mix. Any light commercial mix can start as a base, but should be augmented with about 1/3 to ½ drainage material such as coarse (screened and washed) sand, clean poultry grit, gravel, or sponge rock (such as Perlite). If you use a peat-based mix, you should repot into fresh soil about every two years. Any type of pot (clay, plastic, or ceramic) is acceptable, but must have good drainage (be sure the saucer does not retain water). The pot should only be a bit larger than the size of the root mass; significant overpotting can result in soil moisture retention and root rot. However, these plants are easily potbound, which restricts overall growth. So every year or two increase the pot size until the plant achieves the desired size.

There are a few pests that attack adeniums. Spider mites and mealybugs are the worst problems but are readily treated with normal remedies. These pests are more of a problem if plants are grown indoors or in a greenhouse than if grown outdoors where natural controls (predators, rain) are so important. Mites can be particularly bad on some species and cultivars, building up very rapidly and resulting in total leaf drop. Affected plants will rapidly re-leaf once the mites are controlled. Plants grown outdoors during the summer can occasionally get colonies of large yellow aphids with black legs. This is the same aphid that commonly attacks wild and garden milkweeds.

Desert Rose plants form seed develop vastly the best character with no two plants alike in shape. When your seed pod is fully ripe on the plant, it will split open revealing seeds with beautiful "wings" so that seeds will quickly blow away.

It is an evergreen succulent shrub in tropical climates and semi-deciduous to deciduous in colder climates, is also dependent on the species. It can grow to 1 to 3 metres in height. The leaves are spirally arranged, clustered toward the tips of the shoots, simple entire, sexy in texture, 5 to 15 cm long and 1 to 8 cm broad. The flowers are tubular, 2 to cm long, with the outer portion 4 to 6 cm diameter with five petals, resembling those of other related genera such as Plumeria and Nerium. The flowers tend to red and pink, often with a whitish blush outward of the throat.

The leaves are a glossy green and semi-deciduous, depending on your care and your climate outdoors.

These plants can make massive roots. They are capable of breaking through the sides of plastic and even thin-walled ceramic pots. Many growers use a relatively shallow, bowl-like pot somewhat larger than the root system would dictate. The shallow nature of the pot allows for more rapid drying of the soil mass, while allowing room for root expansion.

Adenium is a genus of spectacular succulents from tropical Africa and Arabia. The species range from shrublets with subterranean or above-ground caudexes to small trees with swollen trunks and stems to 15 feet tall. Their striking forms are further enhanced by some of the showiest flowers of all succulents, often borne in masses over a long season. They adapt readily to container culture in the warmer parts of the world.

Adenium is a small group of plants known from dry climates in sub-Saharan Africa and the very southern part of the Arabian Peninsula. Wild adeniums vary dramatically from location to location, from short fat trees that resemble a small baobab to quite small shrubs arising from huge tuberous roots. One thing that they all have in common is that they live in relatively dry climates (or at least areas that have extended annual dry seasons) and therefore they have adopted the succulent way of life, that is, they store water in their soft, swollen roots and stems to allow them to survive through periods of drought.

If left without added water and no rain for a long time or after a cold night, the desert rose can lose most or all of its leaves. They will re-grow after watering or after warm weather returns. If caterpillars defoliate your plant, its leaves will re-grow anew.

To make your plant develop a large swollen base/trunk, you need a good quality fertilizer. Fertilizer requirement for swelling up trunks is also used to increase flowering. Never apply fertilizer directly on roots and do not liquid feed when a plant is thirsty: always water first slightly to avoid root burn and leaf drop.

Adeniums need bright light for normal growth and flowering. They love the summer thunderstorms and full, day-long sunlight is ideal. If kept too shaded during the growing season, adeniums will develop unnatural, weak growth and will not bloom. All adeniums are very sensitive to frost and cool weather. As evenings begin to cool in the fall, plants should be brought back indoors and placed in a bright location where the temperature will stay above 10°C. Full sun is not necessary for dormant plants. For people with greenhouses, adeniums will thrive under greenhouse conditions throughout the year, but seem to enjoy at least a few good warm, soaking summer rains. These are drought-adapted plants.

In nature, Adenium obesum can assume the proportions of a large shrub or small tree. However, they live quite happily if their size is restricted, and they will bloom faithfully. Size can be restricted by under-potting.

Position Desert Rose in full sun or some afternoon shade for best flowering, but use even less water in partial shade conditions. Select an acid soil mix with plenty of peat moss and organic elements and coarse sand. Be certain the soil mix and the pot drain very well.

The most commonly available forms of the desert rose are Adenium obesumand its various cultivars and hybrids. The most commonly available plants currently are grown from seed and are very similar to the true species found in nature. Young plants have an inflated trunk, sometimes called the caudex. From this fattened caudex arise several slender but soft and succulent stems which are sparsely branched in youth. Even young plants 2 to 3 years old and 6 to 8 inches tall can put on a beautiful floral display, with the pink to red flowers arising from the tips of the stems.

Desert Rose responds amazingly well to food so use plenty of time-released pellet food. Growth will be much faster and flowers will be more prolific as well. With a very well drained soil and pot and with quality fertilizer available, you can water often to stimulate maximum growth and flowering.

Adenium hybrids can be multi-grafted with several colors/varieties on the same plant. The swollen base will be formed only when the rod stock plant is grown from seed.

Many adeniums branch rather sparsely and, even when grown hard, can look leggy after time. Judicious pruning will result in better branching and a fuller-looking plant. Because the flowers are developed at the ends of the stems, a more fully-branched plant will also produce more flowers.

Adenium is a popular houseplant in temperate regions. It requires a sunny location and a minimum indoor temperature in winter of 10 °C. Adenium is typically propagated by seed or stem cuttings. The numerous hybrids are propagated mainly by grafting onto seedling rootstock. While plants grown from seed are more likely to have the swollen caudex at a young age, with time many cutting-grown plants cannot be distinguished from seedlings.

From time to time the plant may be attacked by aphids. Use a water spray or soap solution to keep it clean of pests. Never use chemicals.

Do not wet the leaves. Adeniums need lots of light for heavy flowering. Most hybrids and species start blooming in the spring when the conditions are warm and days get longer and continue blooming through the fall and winter in warmer climates.

Provide ample water during the growing season. If your soil is well drained and the weather is warm and sunny, the roots rapidly absorb soil moisture which is lost through normal transpiration. In well drained soils during active growth in the heat of midsummer, plants can literally be watered daily. Adeniums are becoming favorite landscape plants in tropical parts of the world such as Asia and southern Florida, where rains can be heavy and almost daily through the summer; the plants thrive under these conditions.

All adeniums have highly toxic sap. In Africa the sap has been used to make poison arrows for hunting game. On the island of Socotra where introduced goats have decimated much of the native vegetation, the adeniums are left totally untouched. Use care when handling and pruning plants. Do not get sap in your eyes. If you get sap on your skin, wash promptly. Commercial propagators handle hundreds of plants daily without problems; however, precautions are prudent.

In nature, Adenium obesum is quite variable but can form a small, thick-trunked tree or large shrub. However, its size can be restricted by pot culture, and 20-year-old plants can be quite happy in a 10" pot, being only a foot or two tall. Because their size can be restricted, and because of the unusual shapes, they are becoming increasingly popular subjects for tropical or succulent bonsai. Given the right conditions, they can be fast-growing and rewarding houseplants in most any climate.

The plant exudes a highly toxic sap which is used by some people to coat arrow-tips for hunting.

Adeniums are relatively easy to care for as long as you think of your plant as actually being two quite different plants with different requirements at different times of the year. In summer while in full growth, they should be treated as a tropical plant, watered abundantly and frequently, and fertilized rather generously. In the winter time they need a dry rest, and should be treated like a cactus, with only light occasional waterings during warm bright days.

Restrict water a bit during cooler, cloudy periods, and cut back on watering as fall approaches. Adenium obesum can be kept in leaf almost throughout the year, especially under ideal conditions such as in a warm greenhouse. In this case, light watering is acceptable, especially on warmer days, perhaps every week or two throughout the winter. But in many cases all the leaves will fall off your plant in the early winter. Be particularly careful when watering leafless plants; a monthly watering from October through February is adequate. Some adenium specialists believe that there is better flowering after a totally dry dormant period. Adeniums can be fertilized weekly during the growing season, using any good quality balanced houseplant fertilizer, but only at half the recommended label rate.

Adenium obesum is a shrubby plant. The thickened stems taper gradually upwards and may be rigid and upright or, less commonly, rather weak and spreading. Young plants have a small, ovoid caudex, and old specimens in habitat have large caudexes. Mature plants in cultivation, however, usually lack a distinct one.

Adeniums are generally not self-fertile; it usually requires two separate clones to produce viable seed. They have a complex flower structure and are a bit difficult to pollinate by hand until you learn the trick. However, fresh seeds germinate rapidly, usually in 3 to 7 days, and seedlings tend to be vigorous. Seeds are occasionally available from seed dealers who specialize in tropical or exotic plants.

Adenium obesum is potentially semi-evergreen: if kept warm and well watered, plants will grow and often flower through the winter. Under such conditions they undergo only a brief leaf-drop and dormancy, usually a few weeks in spring or early summer. They can also endure a drought or cold-induced dormancy of several months, which is the normal condition in nature.

Flowering habit is extremely variable and is influenced by both cultural and genetic factors. When grown under ideal conditions of ample heat and water, some clones flower for two to four months; some clones are nearly everblooming. Most plants slow their growth and stop flowering when temperatures exceed about 37 degrees celsius.

Desert Rose is excellent in pots especially for people (like me!) who "kill everything" because Adenium lives with little care and can take a good deal of neglect.

Seed-grown plants are typically vigorous and can be flowered in as little as 8 to 12 months. Cutting-grown plants are equally vigorous; their roots become greatly enlarged in a couple of years and can be exposed when the plant is repotted to make a more interesting specimen. After several years the stems also will have thickened such that cuttings are indistinguishable from seed-grown plants.

Always at its best with some attention, the desert rose will become larger, more interesting and more valuable every year. Large specimens can cost more than S$1,000 for older plants with large bases and a multitude of branches. More branches mean more flowers which are extremely attractive.

(1) Wikipedia

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