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Only occasionally used for bonsai, Adenium is a genus of one to a dozen different species
(depending on the source) of succulents in the family Apocynaceae, from Africa and the
Middle East. Most commonly known as Desert Rose, they are also called Karoo rose, impala
lily, and Sabi star. The species range from 'shrublets' to small trees with swollen trunks
(caduex), growing up to about 15 feet (5m) tall. The main draw of these plants are their
showy flowers in white, pink and red that are in bloom for much of the year in their native
habitat.
With a reputation for being slow growing and finicky, Adenium are actually fast growing
and easy to grow when given the right conditions and the proper care. Desert Roses readily
adapt to container culture, making them well suited for interesting and untraditional bonsai
specimens.
Hardiness: Desert Roses will not survive at temperatures below 50F (10C). For best results,
keep them above 65F (17.5C) at all times. They can be kept outdoors in the summer if you
live in a temperate zone, but bring them in when the temperatures start to drop at nights.
Flower growth becomes suppressed at temperatures above 100F (38C).
Light: Full sun in temperate climates. In very hot, dry climates, they can benefit from afternoon shade. Make sure they receive no
less than a half day or full sun. Young plants can be sun tender, and you can keep the lower portion of the pot in shade to protect
trunks less than around three inches thick.
Soil: A well draining, soiless mix (no organic matter) is a must. They prefer neutral to slightly alkaline conditions.
Watering: While succulents, adenium are *not* cactus. If you think of your Adenium as two different plants, with two different
requirements for watering (active growth and dormancy), you will have little issue. If you ignore this, you are going to have a
very unhappy desert rose.
Popular literature tells us to water them like cactus, but they enjoy, and thrive, when watered more heavily, especially during
warm weather. Water the soil, not the leaves. Do no allow the soil to remain waterlogged, but water thoroughly and allow the soil
to partly, but not completely, dry out between waterings. If you have a fast draining soil mix (like pure akadama/pumice, etc) you
can even water every day with no ill effects. If the soil is allowed to remain dry for a day or two, the tree will be okay, but they
prefer more water than what is simply needed to survive. If treated like a cactus, allowed to remain dry for days, even weeks at a
time, they will become dormant until watering increases, which is not desirable for trees in development. By not allowing the
potting mix to dry out completely in the growing season, you will be greeted with far more vigorous growth than you might
expect.
In winter, unless you can keep them at a temperature of 80F (25C) or higher, then you should start watering them more like a
cactus. Slowly cut back on the amount of water they are given after they are brought inside (this may go down to as little as once a
month). Dormant adenium are very susceptible to over watering, or if kept waterlogged in any season, which can cause root death
and rot.
If you live in a tropical climate, where these can be kept outdoors all year, water well as long as the plant is in active growth. As
growth slows down, decrease the amount of water. Most Desert Rose require a period of dormancy, so watch your plant carefully.
Dormancy is heralded by a drop in water consumption and sometimes the yellowing and dropping of the plant's leaves. Decrease
watering immediately if this occurs. Especially in temperate climates, this will usually coincide with the shortening of days in
autumn. Keep in mind however that partial defoliation of these plants can also occur due to missed waterings and drastic and
sudden changes in weather. Your best bet is to pay attention to your own habits in caring for these plants. Dormancy ranges from
complete defoliation to just a slowing of growth, and some Adenium flower exclusively during their dormancy stage.
In spring, slowly increase water again, watching for new growth. Adenium cannot come out of dormancy without the increase of
water, but too much too soon can cause root death as well.
Adenium love humidity during the growing season. They do not prefer high humidity during their dormancy.
Fertilizer: Adenium respond well to regular feedings. Use an organic gentle balanced liquid twice a week
or a time release fertilizer, something in the 5-5-5 or 10-10-10 range. Unlike many flowering plants,
Adenium require high nitrogen to flower well. Be careful not to get any on the lower trunk or exposed
roots. Inadequate watering and feeding are the primary reasons adeniums have been regarded as
slow-growing. Reduce feed strength in mature specimens. Adeniums prefer constant low levels of feed to
infrequent high doses.
Pests and Diseases: When grown in tropical climates, these plants are rarely bothered by pests (occasional
thrips). In temperate climates when grown indoors part of the year they can have issues with aphids,
scale/mealy bugs, spider mites and whiteflies. Adeniums are sensitive to most pesticides. Insecticidal soaps
and micro-encapsulated diazinon are safe for the plants.
Repotting: Once a year for younger plants in development in temperate zones. Possibly twice a year in tropical areas where they
are growing actively all year round. Growth is severely curtailed in root bound Adeniums, so keeping a more mature tree that has
reached the desired size in a pot for two or three years is fine. Keep in mind that the thick, expanding upper roots of Adeniums
don't care too much how expensive your pot is. Plant quickly growing trees in plastic or wide mouthed, bowl shaped containers
with thick walls or risk pots breaking if you aren't paying attention during the growing season. This tends to be more a problem in
tropical climates than in temperate ones. Repot only during the active growing season. Do not water for a week after repotting if
any large roots were removed or damaged. Root prune lightly, up to about a third of the root mass. If necessary, a single large
root can be removed. If no roots were removed or disturbed, water as normal for the growing season. Adeniums can be
completely bare-rooted with no problems.
Soil level can be slightly lowered with each repotting to slowly expose the thick, fleshy roots. Keep in mind that the newly exposed
roots are sensitive to light, and benefit from being partially shaded for the first few months.
Pruning and Styling: Adeniums branch sparsely without attention, but good pruning will increase branching. And as they bloom
on the tips of branches, better branching also means better flowers.
For best results prune during the growing season. Cut back a branch to the desired length, and several more will sprout from the
area as well as further down the branch and trunk. Remove all but two or three of the new branches from the wounded area.
Pinch new growth down half way to increase branching. These trees will never have delicate ramifications, but they can have fairly
impressive branch structures nonetheless. Healthy, vigorously growing plants can be pruned back hard and drastically to introduce
budding and branching further down the trunk.
Remove weak or inward growing branches. Prune unwanted branches flush with the trunk. Occasionally during a very wet season
a branch may begin to rot. If this occurs, cut down until there is no rot evident (black or brown), and the flesh beneath it all white
and healthy. Be sure to sterilize after each cut, so you do not reinfect the tree when you reach a clean area.
Thick, fleshy basal caudex develop in time on most Adenium without specific help beyond correct watering and fertilizing. Rooted
cuttings may take longer to develop this feature than seed grown plants. Some varieties flower early, in as little as six to eight
months after germinations, while others take several years to reach maturity.
Do not use wire. The branches are fleshy and break easily when bent.
Adeniums do bleed a toxic sap. This is generally not a danger, but take precautions as the sap can cause skin irritation in some
people. Do not eat (this seems like a very obvious thing but...) and do not allow it to get in your eyes.
Propagation: Cuttings (4-6inches) during the growing season. Can benefit from rooting hormone and bottom heat, inserting in to a
coarse rooting mixture (sharp sand is good).
Adenium are not self fertile, requiring two plants to set seeds. Seeds germinate in about a week at temperatures around 85F (28C).
Treating with a fungicide before sowing can increase viable seedlings. Most seedlings will grow through the first winter if kept in
tropical conditions, only hitting a mandatory dormancy in the second year.
Styles and Forms: Styling is limited to the natural growth habits of the plant. If you try to force a particular style on these you will
be sorely disappointed.
Species and Cultivars: Depending on the source, these are listed as separate species or simply varieties of a single species.
A. obesum - This is either one species of several, or the species while all others are varieties of this species. Sources disagree on that.
Relatively long Summer blooming period and it can be kept in growth through winter in a warm and bright location, requiring no
dry dormancy, though if growth slows, decrease water slightly. It is the most widely available species in cultivation and has been
used as one of the parents in many of the hybrids.
A. arabicum - Thick, caduex forming, with thick, fleshy leaves. The most 'succulent' like. Sets seeds with difficulty.
A. bohemianum - Broad leafed with long dormancy requirements and poor flowering. Not generally recommended.
A. multiflorum - Lanky, tall growing, with reddish tinge to the leaves. Will not flower if kept warm and moist through the
dormancy period.
A. somalense - robust and fast growing.
A. swazicum - Uncommon, native to Swaziland. Hardiest of the Adeniums, though rarely set seeds. Slightly droopy habit.
Susceptible to spider mites.
Other Information:
(depending on the source) of succulents in the family Apocynaceae, from Africa and the
Middle East. Most commonly known as Desert Rose, they are also called Karoo rose, impala
lily, and Sabi star. The species range from 'shrublets' to small trees with swollen trunks
(caduex), growing up to about 15 feet (5m) tall. The main draw of these plants are their
showy flowers in white, pink and red that are in bloom for much of the year in their native
habitat.
With a reputation for being slow growing and finicky, Adenium are actually fast growing
and easy to grow when given the right conditions and the proper care. Desert Roses readily
adapt to container culture, making them well suited for interesting and untraditional bonsai
specimens.
Hardiness: Desert Roses will not survive at temperatures below 50F (10C). For best results,
keep them above 65F (17.5C) at all times. They can be kept outdoors in the summer if you
live in a temperate zone, but bring them in when the temperatures start to drop at nights.
Flower growth becomes suppressed at temperatures above 100F (38C).
Light: Full sun in temperate climates. In very hot, dry climates, they can benefit from afternoon shade. Make sure they receive no
less than a half day or full sun. Young plants can be sun tender, and you can keep the lower portion of the pot in shade to protect
trunks less than around three inches thick.
Soil: A well draining, soiless mix (no organic matter) is a must. They prefer neutral to slightly alkaline conditions.
Watering: While succulents, adenium are *not* cactus. If you think of your Adenium as two different plants, with two different
requirements for watering (active growth and dormancy), you will have little issue. If you ignore this, you are going to have a
very unhappy desert rose.
Popular literature tells us to water them like cactus, but they enjoy, and thrive, when watered more heavily, especially during
warm weather. Water the soil, not the leaves. Do no allow the soil to remain waterlogged, but water thoroughly and allow the soil
to partly, but not completely, dry out between waterings. If you have a fast draining soil mix (like pure akadama/pumice, etc) you
can even water every day with no ill effects. If the soil is allowed to remain dry for a day or two, the tree will be okay, but they
prefer more water than what is simply needed to survive. If treated like a cactus, allowed to remain dry for days, even weeks at a
time, they will become dormant until watering increases, which is not desirable for trees in development. By not allowing the
potting mix to dry out completely in the growing season, you will be greeted with far more vigorous growth than you might
expect.
In winter, unless you can keep them at a temperature of 80F (25C) or higher, then you should start watering them more like a
cactus. Slowly cut back on the amount of water they are given after they are brought inside (this may go down to as little as once a
month). Dormant adenium are very susceptible to over watering, or if kept waterlogged in any season, which can cause root death
and rot.
If you live in a tropical climate, where these can be kept outdoors all year, water well as long as the plant is in active growth. As
growth slows down, decrease the amount of water. Most Desert Rose require a period of dormancy, so watch your plant carefully.
Dormancy is heralded by a drop in water consumption and sometimes the yellowing and dropping of the plant's leaves. Decrease
watering immediately if this occurs. Especially in temperate climates, this will usually coincide with the shortening of days in
autumn. Keep in mind however that partial defoliation of these plants can also occur due to missed waterings and drastic and
sudden changes in weather. Your best bet is to pay attention to your own habits in caring for these plants. Dormancy ranges from
complete defoliation to just a slowing of growth, and some Adenium flower exclusively during their dormancy stage.
In spring, slowly increase water again, watching for new growth. Adenium cannot come out of dormancy without the increase of
water, but too much too soon can cause root death as well.
Adenium love humidity during the growing season. They do not prefer high humidity during their dormancy.
Fertilizer: Adenium respond well to regular feedings. Use an organic gentle balanced liquid twice a week
or a time release fertilizer, something in the 5-5-5 or 10-10-10 range. Unlike many flowering plants,
Adenium require high nitrogen to flower well. Be careful not to get any on the lower trunk or exposed
roots. Inadequate watering and feeding are the primary reasons adeniums have been regarded as
slow-growing. Reduce feed strength in mature specimens. Adeniums prefer constant low levels of feed to
infrequent high doses.
Pests and Diseases: When grown in tropical climates, these plants are rarely bothered by pests (occasional
thrips). In temperate climates when grown indoors part of the year they can have issues with aphids,
scale/mealy bugs, spider mites and whiteflies. Adeniums are sensitive to most pesticides. Insecticidal soaps
and micro-encapsulated diazinon are safe for the plants.
Repotting: Once a year for younger plants in development in temperate zones. Possibly twice a year in tropical areas where they
are growing actively all year round. Growth is severely curtailed in root bound Adeniums, so keeping a more mature tree that has
reached the desired size in a pot for two or three years is fine. Keep in mind that the thick, expanding upper roots of Adeniums
don't care too much how expensive your pot is. Plant quickly growing trees in plastic or wide mouthed, bowl shaped containers
with thick walls or risk pots breaking if you aren't paying attention during the growing season. This tends to be more a problem in
tropical climates than in temperate ones. Repot only during the active growing season. Do not water for a week after repotting if
any large roots were removed or damaged. Root prune lightly, up to about a third of the root mass. If necessary, a single large
root can be removed. If no roots were removed or disturbed, water as normal for the growing season. Adeniums can be
completely bare-rooted with no problems.
Soil level can be slightly lowered with each repotting to slowly expose the thick, fleshy roots. Keep in mind that the newly exposed
roots are sensitive to light, and benefit from being partially shaded for the first few months.
Pruning and Styling: Adeniums branch sparsely without attention, but good pruning will increase branching. And as they bloom
on the tips of branches, better branching also means better flowers.
For best results prune during the growing season. Cut back a branch to the desired length, and several more will sprout from the
area as well as further down the branch and trunk. Remove all but two or three of the new branches from the wounded area.
Pinch new growth down half way to increase branching. These trees will never have delicate ramifications, but they can have fairly
impressive branch structures nonetheless. Healthy, vigorously growing plants can be pruned back hard and drastically to introduce
budding and branching further down the trunk.
Remove weak or inward growing branches. Prune unwanted branches flush with the trunk. Occasionally during a very wet season
a branch may begin to rot. If this occurs, cut down until there is no rot evident (black or brown), and the flesh beneath it all white
and healthy. Be sure to sterilize after each cut, so you do not reinfect the tree when you reach a clean area.
Thick, fleshy basal caudex develop in time on most Adenium without specific help beyond correct watering and fertilizing. Rooted
cuttings may take longer to develop this feature than seed grown plants. Some varieties flower early, in as little as six to eight
months after germinations, while others take several years to reach maturity.
Do not use wire. The branches are fleshy and break easily when bent.
Adeniums do bleed a toxic sap. This is generally not a danger, but take precautions as the sap can cause skin irritation in some
people. Do not eat (this seems like a very obvious thing but...) and do not allow it to get in your eyes.
Propagation: Cuttings (4-6inches) during the growing season. Can benefit from rooting hormone and bottom heat, inserting in to a
coarse rooting mixture (sharp sand is good).
Adenium are not self fertile, requiring two plants to set seeds. Seeds germinate in about a week at temperatures around 85F (28C).
Treating with a fungicide before sowing can increase viable seedlings. Most seedlings will grow through the first winter if kept in
tropical conditions, only hitting a mandatory dormancy in the second year.
Styles and Forms: Styling is limited to the natural growth habits of the plant. If you try to force a particular style on these you will
be sorely disappointed.
Species and Cultivars: Depending on the source, these are listed as separate species or simply varieties of a single species.
A. obesum - This is either one species of several, or the species while all others are varieties of this species. Sources disagree on that.
Relatively long Summer blooming period and it can be kept in growth through winter in a warm and bright location, requiring no
dry dormancy, though if growth slows, decrease water slightly. It is the most widely available species in cultivation and has been
used as one of the parents in many of the hybrids.
A. arabicum - Thick, caduex forming, with thick, fleshy leaves. The most 'succulent' like. Sets seeds with difficulty.
A. bohemianum - Broad leafed with long dormancy requirements and poor flowering. Not generally recommended.
A. multiflorum - Lanky, tall growing, with reddish tinge to the leaves. Will not flower if kept warm and moist through the
dormancy period.
A. somalense - robust and fast growing.
A. swazicum - Uncommon, native to Swaziland. Hardiest of the Adeniums, though rarely set seeds. Slightly droopy habit.
Susceptible to spider mites.
Other Information:
Desert Rose (Adenium)
I dream of fire
Those dreams that tie two hearts that will never die
And near the flames
The shadows play in the shape of the mans desire
Those dreams that tie two hearts that will never die
And near the flames
The shadows play in the shape of the mans desire
This desert rose
Whose shadow bears the secret promise
This desert flower
No sweet perfume that would torture you more than this
Whose shadow bears the secret promise
This desert flower
No sweet perfume that would torture you more than this
-Sting, Desert Rose
| Open Source image from wiki commons. Adenium showing swollen basal caduex |
| Open Source image from wikicommons. |