The attractive desert rose (Adenium obesum) is a pleasing ornamental plant. Also known as Mock Azalea or Dwarf Bottle Tree, these tropical succulents are pleasingly low maintenance. Prized for their showy, trumpet shaped blooms, desert rose is also easy to grow. When in flower these plants are an eye catching feature, standing out in any home or garden.
An attractive ornamental plant, Adenium obesum is surprisingly easy to care for.
Hardy in the warm, tropical climates of USDA Zones 11 and 12. In other areas it is popularly grown as a colorful houseplant. You can also grow Adenium obesum in pots, placing the plants outside in the summer and bringing them undercover for the fall and winter months.
The ideal plant for a novice or an experienced gardener, here is your complete guide to growing a desert rose.
What is a Desert Rose?
Desert rose is an attractive succulent. It is primarily grown for its deep pink flowers and thick succulent stem.
The only Ademium in wide cultivation, desert rose is a member of the Apocynaceae family. The plant originates in Madagascar, the Middle East and Africa. While it is the only Adenium in common cultivation, the range of hybrid varieties on offer means that you can also find different colored, striped and variegated varieties.
A slow growing plant, Adenium obseum rarely grows more than 12 inches a year. This makes it an easy plant to maintain because it rarely overgrows its position. If allowed to, the plants can reach a height of about 6 ft.
The distinctive caudex of the plant helps Adenium to stand out amongst other succulents.
It is the swollen trunk, or caudex, that sets desert rose apart from other tropical succulents. A fat trunk is a sign of a healthy plant. If your plant has a skinny trunk it requires more moisture.
Warning desert rose has a milky sap that contains lethal toxins. This means that all parts of the plant are considered toxic. Dogs and cats become sick just by licking the plant. Contact a vet or animal poison control immediately.
Keep your desert rose plant out of reach of children and pets. Always wear gloves when handling the plant, and wash your hands afterwards.
Different Varieties of Desert Rose
The standard variety of Adenium obesum produces attractive pink flowers. If you want something a little different there are a number of other, mainly hybrid, varieties available.
Red desert rose produces dramatic scarlet blooms. While white desert rose produces single or double white blooms.
Double desert rose has two to three times more petals than the more common single flowering varieties. The double desert flowers are less trumpet-like in shape. Instead they bear more of a resemblance to the typical rose flower. Purple desert rose produces blooms in shades of lavender or purple.
Single flowering pink blooming varieties are most common. But with a little research you will find a range of colorfully attractive plants.
Picotee types produce flowers edged in contrasting colors, usually white blooms with pink or red edges. You may also find striped Adenium obesum varieties for sale. These produce eye catching blooms with petals that are striped, or streaked, in contrasting colors.
Variegated cultivars produce foliage that is of interest even when the plant isn’t flowering. These eye-catching plants produce leaves edges or striped in shades or yellow, cream and white.
Most garden centers and stores stock at least one variety of desert rose. The plants are also commonly seen in department stores and home improvement centers. However if you want a slightly more dramatic plant, you may need to contact a specialist nursery.
Finding the Ideal Position For Your Desert Rose
Desert rose prefers full sun locations and well draining soil. The closer you are able to replicate its native conditions the more the plant will flower.
Adenium obesum is a full sun loving plant. If you are growing the plant outside it appreciates a little shade from the afternoon sun. This helps to protect the leaves from sunburn.
Hardy only in USDA Zones 11 and 12, desert rose won’t survive frosts or cold winters.
The soil should be dry and well-draining. A sandy or gravelly soil is ideal. The soil pH level should be about 6.0. Try to avoid planting in extremes of this. Soil testing kits are easy to use if you are unsure of the makeup of your soil. A reliable soil test kit provides you with valuable information that makes plant care a lot easier.
Desert rose plants like temperatures to be consistently warm. If growing as a houseplant, avoid placing near heaters or in draft positions.
A light, well draining position helps the plants to thrive.
Adenium obseum won’t survive exposure to temperatures below 50 ℉. If you are growing it as a houseplant, aim to keep the temperature 65 and 90 ℉.
Humidity is less important than constant, consistent heat. Remember, these plants thrive in the hot, dry desert climate.
A south facing window in a bright room is ideal. Rotate the plant regularly to encourage even growth. If you are unable to provide an indoor position that is light enough, place the plant under a grow light.
Desert rose is deciduous in cooler positions. Those growing in pots or as houseplants can be kept in leaf throughout the year if placed in a warm position and watered correctly.
How to Plant
Desert rose is best planted in the spring.
Remember to wear gloves when handling the plants.
While commonly grown as a houseplant, gardeners in the warmest climates will be able to grow desert rose as an outdoor plant.
If you are planting outside, try to plant on a slope. This encourages water to drain away quickly after periods of heavy rain. Alternatively, mound the soil up and plant your desert rose on top of the mound. This elevates the plant above the natural level of the soil and encourages water to drain away from the plant.
Work the soil over well before planting. Remove any weeds that may smother your plants. Stubborn weeds can be treated with an effective homemade weed killer.
Make a shallow hole in the soil. Spread the roots of the plant out and place in the hole. Cover lightly with soil. Don’t water immediately. Instead wait a week before watering, this gives the plant time to settle in its new position..
Planting in Pots
Most people find it easier to grow desert rose plants in pots.
Repot when the plant shows signs of being rootbound. This is about once every 3 years. You also need to report if you suspect the plant is suffering from root rot. Repotting can be done at any time of year, but is best done during the spring or summer months.
Thick, bowl shaped pots, such as these Zoutog Ceramic Succulent Pots, are preferred. These pots provide ample room for the roots of the plant to fan out. They are also shallow enough for the soil to dry out quickly, preventing root rot. Porous containers, such as terra-cotta pots are also a good choice. These allow air to circulate through the soil, helping it to dry out and preventing plants from becoming overwatered.
Fill the pot with either succulent or cacti potting soil. You can also use potting soil mixed with equal parts sand or perlite. This creates a well draining mix.
When repotting, make sure that the soil is completely dry before carefully removing the plant from the pot. Brush old soil away from the root system. Remove any rotten or dead roots. Cuts on the roots can be treated with a fungicide or antibacterial solution.
Make a shallow hole in the fresh potting soil. It should be large enough to hold the spread out root system of the plant. Position the plant in the hole, spreading out the roots as you pot. Lightly cover the roots with fresh potting medium.
Allow the plant to dry out for about a week before starting to lightly water. This gives the plant time to repair any damaged roots. Gradual watering also helps to prevent root rot.
Many growers like to lift their plants to expose the engorged caudex above the soil line. Don’t begin lifting and exposing the caudex until the plant is at least 3 years old. To do this, when repotting, mound the soil so that you can pot slightly higher than the soil line. A newly exposed caudex is prone to sunburn. Gradually increase the amount of direct sunlight the plant is exposed to.
Caring for a Desert Rose
If cared for properly desert rose plants will reward you with a thick caudex and lots of blooms. They are also surprisingly resilient and hard to kill.
How Often Should I Water?
Remember that these plants are succulents. In the wild they enjoy wet periods, during which they grow, followed by dormant, dry spells. Replicating this natural cycle with your watering routine helps the plant to thrive.
It may help if you try to treat the plant as a tropical during the spring and summer months and a succulent during the fall and winter. This means keeping the soil evenly moist during the spring and summer months. In the winter and fall reduce watering to no more than once a month.
If you are unsure when to water look at the caudex of the plant. A hydrated plant has a thick central stem. A thin stem is a visible sign that the plant requires more water.
The gentle spray of a watering can helps to ensure that you aren’t overwatering your plants.
Check the soil every few days during the growing season. Water only when it is completely dry. The Gouven Soil Moisture Meter provides an accurate reading of the soil’s moisture content.
Water slowly, carefully saturating the soil. Don’t allow pools of standing water to form on the soil. This can cause roots to become waterlogged and rotten. You may find it easier to water with a watering can than a hosepipe. This allows you to better control the amount of water you are giving your plants.
If you are watering outdoor plants, water during the coolest part of the day.
Do I Need to Fertilize my Plants?
Fertilize the plants only when they are actively growing.
To fertilize, dilute an evenly balanced fertilizer to half its strength. Apply once a month during the spring and summer. Don’t apply during the fall and winter.
A water soluble or liquid fertilizer is easily incorporated into watering routines. A slow release granular fertilizer can also be used. This can be applied once in the spring and, if necessary, again in the summer.
Outdoor plants growing in pots that are brought inside in the fall can also be given a light or weak dose of balanced fertilizer during midwinter. This is not always necessary, particularly if the plant is semi-dormant.
How to Prune a Desert Rose
Pruning is useful for a number of reasons. Firstly, cutting back Adenium obesum encourages more stems and therefore more flowers to emerge. Regular pruning and under-potting you plants, allowing them to sit in pots that are slightly too small for their root system, helps to keep growth incheck. Finally, regular pruning during the growing season also keeps your desert rose looking fresh and neat.
Prune as early as possible, before new growth begins. Desert rose sets blooms on new growth. Pruning as new growth emerges can deter flowering. Cold damage should be removed as soon as new growth emerges.
Remember to sterilize your tools before and after use. Sterilize the blades between each cut if you are pruning away diseased growth.
When pruning try to make cuts just above the leaf node, this is the point where one stem joins another. Making cuts at a 45 degree angle helps to create a more natural appearance.
During the growing season pinch back or prune unruly growth and unwanted stem tips.
Prune away leggy branches to improve the shape of the plant. These cuttings can be used for propagation. Cut back long or lanky shoots to the same height as the rest of the plant. Finally, remove any contacting or cross branches.
If the plants are placed outside for the summer, prune as you bring them in for winter. Use a sharp garden scissors to remove unnecessary growth. This enables the plant to make the most of its dormant period. You can also trim the plant, removing dead or damaged vegetation in the spring before you place it outside.
Common Problems and How to Solve Them
If cared for correctly this succulent is pleasingly problem free. Regularly check your plants for signs of infestation. Spider mites, scale and mealybugs can all target the plants. Remove infestations by wiping the foliage with insecticidal soap or cotton wool dipped in an alcohol wipe.
Pay particular attention to your desert rose plants during warm spells, or if humidity is high. Remove any stems and foliage that display signs of powdery mildew.
Plants may fail to flower for a while after repotting, while they adjust to their new environment. Not watering for a week after planting helps the plant to adjust. A lack of light can also prevent flowering. An application of phosphorus fertilizer or bone meal encourages flowering.
Flowering can take time to resume after repotting. Be patient and give your plants time to settle in their new position.
Yellowing foliage can be a sign of underwatering. It can also be a sign of stress. This is common after purchasing a new plant or repotting.
How to Propagate
Propagation via cuttings is the easiest method.
Take a cutting from the tip of a healthy branch. Place the cutting in a safe place and allow it to dry out. After a few days a callus should form over the cut area.
Take cuttings from healthy branch tips.
Plant the cutting, callused end down, into a pot filled with well draining potting medium. Some growers like to dampen the callused end of the cutting and dip it in rooting hormone before planting but this is not necessary.
Gently water the soil every day. Allow the water to drain away. Don’t allow the soil to become overly saturated. You can also mist the cutting with a spray bottle. The Mayev Spray Bottle has an adjustable nozzle, meaning that you can dampen the plants with a fine spray that won’t overly disturb them.
Roots should form in 2 to 6 weeks.
As the plant grows gradually expose the caudex. To encourage the plants to develop the bulbous stem start off your cutting in a tall thin container. As the plant grows, transplant it into a shorter container.
While you can produce plants with the distinctive bulbous stem from cuttings, the only way to guarantee producing new plants with the distinctive bulbous stem like structure is to propagate from seed.
Growing from Seed
Adenium obesum can be slow to mature. It can take months to flower and years to produce a seed pod. While plants as young as 4 years old can form seed pods it is not until the plants are at least 8 years old that the seeds become viable.
Desert rose seeds form inside bean shaped seed pods. The seeds are small and attached to a fluffy pappus, similar to dandelions. Allow the pods to mature and ripen on the plant. To prevent the pods from splitting and spreading their seeds before you are ready, place a bag over the pod and tie in place.
Seed pods usually appear in pairs. As it ripens the pod swells. It can take several months for the pod to ripen and open. Once the pod splits carefully remove the bag, taking care not to spill any seeds.
Fresh seeds are more viable than older seeds. The seeds can be planted with the fluffy pappus attached but it can also be removed if you find it easier.
Sow the seeds in a tray filled with fresh potting soil mixed with vermiculite. Cover the seeds lightly.
Place the tray in a warm area or on a heat mat such as the iPower Seedling Heat Mat. This helps you to maintain a constant temperature of between 80 and 85 ℉. In ideal conditions, germination takes 3 to 7 days.
Following germination allow the seeds to grow on. Carefully repot the seedlings into individual pots once they are large enough to handle. This is usually about a month after germination.
As the young plants grow, care for them as you would larger desert rose plants.
Adenium obesum is an eye catching, easy to care for plant that, with a little care, grows in a range of conditions.
Desert rose is an eye catching addition to any garden or houseplant collection. A low maintenance succulent, with careful care these plants can reliably flower for many years.
Pleasingly easy to grow, it is easy to see why the desert rose is such a popular houseplant. Why not add one to your collection?