By: Bonnie L. Grant, Certified Urban Agriculturist
Plant lovers are always looking for easy to grow, unique plants with a fun aspect. These East African and Arabian natives are wonderful in the interior container garden or as warm climate additions to the patio display. Caring for desert rose plants requires a full sun location and well-drained soil. Properly mimicking their native regional conditions will garner plenty of rose-like blooms on an architectural marvel of a plant.
Desert rose has become a popular ornamental garden plant in United States Department of Agriculture zones 10 to 11. The rest of us in cooler zones will have to resort to growing Adenium indoors, giving the plant a vacation in the summer on the patio or deck. Desert rose plant care can be difficult and requires some knowledge of the life cycle of the species.
Follow some basic Adenium desert rose growing tips for healthy plants that won’t disappoint with full crowns of richly colored tubular flowers.
Adeniums are succulent, tropical plants. They are distinctive among the class because they develop a caudex, or swollen trunk. All succulent plants have some sort of water storage system, be it leaves, stems or roots. In desert rose, the trunk swells to conserve moisture for times of drought. A nice fat trunk is an indicator of plant health. A skinny stem can indicate that the plant requires more moisture.
An interesting bit of desert rose plant info is its natural resemblance to a bonsai plant, with a short stature when mature, and tidy canopy perched atop the graduated stem. Many growers seem to have trouble caring for desert rose plants, but these can truly be easy to maintain if you keep in mind the water, temperature and lighting needs of Adenium.
First, remember that Adenium plants are native to regions with poor, gritty soil and hot, sunny climates. You can’t expect the plant to thrive in overly moist soil, in a site with limited light. They are also not frost tolerant and will succumb to a freeze if exposed. The plant will not survive long if exposed to temperatures below 40 degrees F (4 C) but will thrive in temperatures reaching up to 90 degrees F (32 C).
Desert rose succulents like bright light, so a southern window exposure provides enough sun for the plants to flourish and bloom. In the garden, choose a sunny location that has some protection from noonday sun, as this can scorch the foliage.
Soil is very important. Adenium plants should have a mixture of cactus soil with gritty sand or lava rocks for good drainage.
The one thing that will kill these plants quickly is improper watering. They are succulents but are used to rainy periods during which they grow, followed by a dormant, dry period. Match your watering practices to these needs for best success. Keep soil moderately moist in spring and summer, but reduce watering in fall and especially winter when the plant is dormant.
Fertilize with a dilution by half of a 20-20-20 liquid plant food once per month when the plant is actively growing. Do not feed the desert rose during winter.
The most common pests are scale, mealybugs and spider mites. Use cotton balls soaked in alcohol to wipe away these insect rogues.
Be cautious, as Adenium desert rose is in the Dogbane family, with all species bleeding a poisonous sap that can irritate skin and mucous membranes.
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Adenium desert rose is widely known by its deep red flowers and a swollen succulent stem. It is frequently referred to as Adenium Obesum, the plant which growth mainly depends on pruning and variety. Be very careful with the sap of Adenium desert rose, as it is poisonous and should not come into contact with pets and children.
When desert rose, or Adenium Obesum, grows on its own, it can reach 10 feet, though there are common cases, when the plant reaches 15 feet. To ensure that the plant has enough soil for proper growth, it should be repotted in a large container. New growths can be pruned and the plant can be easily shaped during the time of its most active growth (during spring and summer months).
Adenium obesum (also known as a Desert Rose or a Karoo Rose) is a succulent plant that is able to store water within its stem and branches through periods of little to no rainfall. As such, it is a wonderful plant for containers due to its drought tolerant nature and its unusual, beautiful shape.
At SummerWinds Nursery, we have many sizes and varieties to choose from available seasonally, while supplies last.
April through October, Adeniums grow best outdoors in the full sun (if large and well established - 10" pot or larger), otherwise outside in filtered full sun/light shade.
Bring Adeniums in containers indoors for the winter to avoid freezing and place in a south or west window.)
For the best rate of growth and healthiest Adeniums, water regularly. Wait to water the Adenium until the soil is almost dry at 1-2" deep.
Fertilizers should only be applied while your Adenium is actively growing (not during winter dormancy—usually some time in November until late March).
During it's growing season (approx. April thru November), Adeniums in outdoor containers can be fertilized with a full strength application of general purpose fertilizer every two weeks alternatively a half-strength solution applied once a month during April - October will be adequate if being grown indoors in a very well lit location with many windows.
Adeniums will not survive a frost. If brought indoors and the temperature is over 55 degrees, dormancy may need to be forced by withholding all water until the leaves drop. Adenium plants may try to grow indoors over the winter if temperatures are too high (70 degrees or higher). Winter growth is NOT recommended, as dormancy will provide a stronger, more beautiful plant and structure.
Adeniums can be overwintered outdoors under a porch roof or on the south side of your home, etc. if the temperature is under 50 degrees and they are kept in a place that is absoutley frost-free and DRY (from both rain and watering). If temperatures drop under 20 degrees, then extra care and frost protection measures are required.
Adeniums are naturally slow growing mostly due to their need for minimal water. This makes for their interesting and unusual growth forms. Water them according to the growth rate and shape you desire.
Flowering generally begins late winter or early spring, often before the plant leafs out. It may stop during the hottest part of the summer (mid-May thru June), and then continue to bloom again into the fall.
Adeniums prefer well drained soil (soil drains within a matter of seconds after being applied). A soil such as E.B. Stone Cactus Mix will work well. Alternatively, you may choose to use your own soil recipe.
Adeniums will tolerate being pot bound without ill effects. Repotting should only be done early/mid-way through the growing season. Make certain not to replant it any deeper than it was. Adeniums can be watered within a day or two of repotting.
Adeniums are rarely subject to diseases, but are occasionally hosts for one of three insect pests--mealy bugs, aphids and spider mites. Outdoor growing often prevents these problems. However, if they occur, a treatment may need to be repeated several times for complete control.
Source: The Desert Botanical Garden, Desert Gardening Guides.
The desert rose needs plenty of water, but cannot survive in standing water. Make sure that the pot you choose has superb drainage to prevent standing water. Terra cotta or ceramic pots are best. You also want to ensure that it has full sunlight daily and has soil that allows proper drainage for its best growth. Using a mixture of two parts loam and one part course sand will allow proper drainage. Making sure the desert rose is planted in a container that can be easily moved when the weather demands and has great drainage will allow you to have a succulent plant year round.
This is the most important thing in desert rose care:
Sunlight: The desert rose is perfect for a sunny window because it needs full sunlight daily. To help the plant grow a straight, strong, stem it is important that your rotate the pot every two to three days especially in young plants.
Temperature: The plant's natural habitat is in the rainforests of Africa and Arabia so it is important that the temperature is kept at a minimum of 50ºF at all times. At 60ºF or higher it may retain its leaves all winter.
Soil: The soil needs to allow for optimal drainage and an ideal pH of 6.0 (slightly acidic).
Humidity: Modern heating systems will cause the water to evaporate more quickly. During the winter months placing your pot into a shallow tray of pebbles with water added is a great way to help the plant retain moisture.
Test the moisture of the soil by inserting your finger into the soil, if it feels dry it is time to water your desert rose. Use a drip pan when you water your plant. Water the plant until the water begins to drip into the drip pan. Empty the drip pan after each watering, you may have to check back after a few minutes to see if it needs to be emptied again. You always want to water your adeniums thoroughly each time 2-3 times a week during spring and summer, and 1 time a week during fall and winter. Do not be afraid to leave the plant while you go on vacation, it can live several weeks without water. You do want to watch for excess water though, as the desert rose is extremely susceptible to root rot. If you use a proper soil and pot, you will not have a problem.
Spring, Summer & Fall: As long as the nightly temperatures do not drop below 40ºF, the bonsai can be left out on the patio or in the garden.
Winter: During the winter when the temperatures begin to near 40ºF, it is time to bring the bonsai inside. Place the plant in a window that is facing the south so that it can receive as much sunlight as possible. It is normal for the Desert Rose to lose some of its foliage, if not all during the winter months.
Always use the products label recommendation for pot size to ensure you use the proper amounts of fertilizer. In the spring you want to use a soluble fertilizer every two weeks. In early summer, when the plants' growth rate slows, stop using the soluble fertilizer and make one application of a slow-release palm specialize fertilizer. In early fall, about two months later, apply the slow-release palm specialized fertilizer one more time.
This desert rose care tip in essential to promote growing. Trimming and pruning your desert rose in the spring will help it grow more branches and more foliage for a fuller more lush plant. When trimming and pruning you want to cut back the new growth as far as you can without cutting off too much. The plant needs some new growth to help it remain healthy. How much you trim back depends on how small you want your desert rose to remain.
Mid spring is the best time to repot your desert rose. You want to wait for warmer weather as not to damage your plant. You also want to wait for some of the new growth to develop so that you can do some trimming and pruning before you repot. Stop water your plant so that the soil can dry out, you want the soil to be dry before you repot. Make sure you knock the dirt of the roots and remove any dead or rotted roots and treat any cuts it may have with a fungicide. When you put the plant into its new pot, fill with dirt as you go along so that you can spread the roots and give them room to grow. After you have repotted the plant, wait a week or two before you give it water. Slowly build back up to its large amounts of water to prevent root rot.
Propagation from a Seed:
Make sure your seed is fresh and place it in a container filled with a well-draining growing medium such as perlite or a sand and soil mix and just cover. While keeping your seed between 80ºF and 85ºF you need to water them from below daily and from above once every three days. Once the seedling appears only water it from below until it is large enough to transplant. You will see the seedling bloom in the same year.
Propagation from Cuttings:
After you have let the cutting from the tip of a branch dry out for a day or two, water the end of the cutting. Then dip the end into a rooting hormone and plant it in a well-draining growing medium. Water and spray with a mist daily making sure it is draining well. In about 2-6 weeks it will take root. When it is big enough, transplant into a more permanent container.
Root Rot: Root rot can kill the desert rose if not treated quickly and properly. Although the stem may feel slightly soft when it needs water, root rot will gradually spread through the entire plant. If the area is soft and fleshy in small areas you need to use a sterilized knife to cut out the rot. You can use household disinfectant and the wound will heal after a few weeks of proper care and watering.
Pesky Pests: Spider mites, scale and meal bogs commonly plague the desert rose. Use an insecticidal soap (oil-based insecticides will damage the foliage) to saturate the plants foliage, then repeat one week later. If the bugs are still present use the insecticidal soap on a cloudy, cooler day.
Simply ensure your plant has plenty of sun, remains warm, and has adequate amounts of water. With proper care and treatment you can grow your desert rose anywhere. Learn more about how to grow desert rose and desert rose care tips in this video:
The Desert Rose plant have acquired a reputation for being slow growing, but they are in fact fast growing and easy to grow when given proper care.
One common myth is they can't tolerate regular watering. I have had seedlings that have gone soft at the base because I didn't water them enough. Once this occurs it is hard to correct. They grow like a tropical plant, except when they are in dormancy (which is around winter). Dormancy is caused when night temps start getting around 15 degrees. This is the time to reduce watering and feeding. Dormancy is often signaled by sudden yellowing and dropping of most or all of the leaves in the colder months. I have also seen this happen if plants are too dry or a change in weather, but plants usually recover quickly.
If you want a display around the outside of the house I find they grow well in clay, stone or concrete pots with slow release fertilizer mixed in the soil and you can add some organic fertilizer with it also. Maybe these types of pots keep them warm in the cooler months.
Potting mixes are a hot topic among growers and are subject to a lot of debate, but if you stick to a well drained and aerated mix for your plants they should grow fine. Some people suggest sand, volcanic rock, crusher dust etc but there is no set rule from my experience, just regular watering and feeding in the hotter months and a well drained mix. Full sun is the best to grow in my experience but adenium can also grow well in at least half a day sun like up against a house or on a patio. In extreme parts of Australia plants can get burnt on the extreme hot days but is usually more of a problem in younger plants.
You can also graft them to produce a plant with different colours. I find the v graft the easiest but remember to sterilize the knife!
Root rot can be a problem if plants are too wet but this is normally not a problem if you have a well drained and aerated mix. If you have an issue with this treat plant with fungicide and there is a chance you could save it.
Pests are mainly mealy bugs, spider mites and stink bugs (orange with black spots). In my location spider mites are the most common pests.
Remember this is my adenium growing guide and different methods will work in different locations in Australia. Contact our garden nursery if you want to purchase these versatile drought hardy plants.
If you want more information on pests and diseases visit the link.
The best bonsai pots for Adenium obesum are shallow because this promotes a larger exposed root or caudex while simultaneously providing ample width for the spread of the caudex.
A standard bonsai pot or creative use of some other shallow container will work well.
Just be sure the container has ample drainage holes.
Generally speaking, mid-summer is the best time to repot a bonsai.
At this time, you should gently remove the tree and surrounding soil from its pot and rinse the roots clean.
Prune off about a quarter of the plant’s root mass from the sides and bottom.
Clean and prepare the plant’s original pot or give it a new pot not significantly larger than the original.
Remember to place a piece of plastic screen over the drainage holes to prevent loss of substrate when watering.
Pour a thin gravel layer over the entire surface of the bottom of the pot, then add a layer of well-draining potting mix thick enough to elevate the tree to the proper height within the pot.
Place the tree on this layer of soil and add soil around the root mass.
Be careful to tamp the soil gently to fill any vacant spots.
Work the new soil under and around the root mass so there will be no air pockets.
Water the repotted bonsai thoroughly by submerging the entire pot into a tub or bucket of water.
Allow it to soak for a few minutes then set it out to drain.
At this time, decorate the surface of the soil with stones, bark, moss, and other natural ground coverings to help hold the soil in place and retain moisture.