Desert rose

Desert rose: how do you recognise it?

Habit

Succulent shrub or small tree up to 80 cm tall and 60 cm wide in a pot, with a swollen, grey-brown base and thick branches.

Leaves

Spoon-shaped to oblong, 5–15 cm, glossy dark green, in rosettes at the branch tips. They drop during the rest period.

Flower

Trumpet-shaped, 4–6 cm across, with five broad lobes, from May to September.

Colour

Pink to red, often with a white throat; also white, and double or striped in some varieties.

Caudex

A thick, water-storing base that grows with the years. Each time you repot, you can raise it a little so it shows off better.

Sap

White and highly toxic; it oozes from every wound.

Flowering: May–September · Plants: March–April · Pruning: March–April

Why grow it?

• A living sculpture: the thick, gnarled caudex makes every plant unique.
• Large trumpet flowers in pink, red or white, from May to September.
• Needs little water: ideal if you sometimes forget a plant.
• Can live for many years and becomes more beautiful with age.
• Can go outdoors in summer, on a sunny patio.
• Easy to shape by pruning, like a bonsai.

Desert rose: where does it grow best?

• As much sun as possible: a south-facing window or a conservatory is ideal. With too little light it stretches and does not flower.
• Very open, free-draining compost: cactus compost mixed with a third of coarse grit, perlite or pumice.
• Dry: water only when the pot is almost completely dry. Wet feet make the caudex rot.
• Warm: 20–30 °C in the growing season, never below 12 °C in winter.
• From June to September it can go outdoors in a warm, sunny spot sheltered from rain, as long as nights stay above 15 °C.

Light

Sunny

Potting soil

Cactus compost

Acidity

Neutral

Watering

Sparingly

Size

0.8 m tall, 0.6 m wide

Temperature

Minimum 12 °C

Goes well with

• Madagascar palm: A related succulent with a thick, spiny trunk and the same care.
• Aloe: Fleshy rosettes that are just as fond of sun and little water.
• Cacti: A small group on the same sunny windowsill, with the same dry winter rest.
• Jade plant: An evergreen succulent that stays green in winter beside the bare desert rose.

Desert rose: when and how to plant it?

Plant in March–April.

1. Repot in March–April, at the start of the growing season, every two to three years.
2. Choose a wide, rather shallow pot with a large drainage hole; terracotta dries out faster and is ideal.
3. Put a layer of gravel or clay pebbles in the bottom and fill with cactus compost mixed with coarse grit or perlite.
4. Wearing gloves, take the plant out of its pot, shake off the old compost and cut away rotten or dead roots.
5. Set the plant at the same depth or slightly higher, so the caudex remains nicely visible.
6. Wait a week before watering so damaged roots can dry and heal.

Care

Watering

From April to September, water thoroughly as soon as the compost is almost dry. In winter hardly at all, especially once it has dropped its leaves.

Feeding

From April to August, once a month with a liquid feed for cacti or flowering plants at half strength.

Light

Turn the pot now and then so it grows evenly.

Moving outdoors

After winter, let it get used to full sun gradually, or the leaves will scorch.

Repotting

Every two to three years in March–April, in fresh, open compost.

Tip: Give it the sunniest spot in your home and keep it dry in winter when it drops its leaves. Wear gloves when pruning and wash your hands afterwards: the milky sap is highly toxic.

Desert rose: when to prune it?

Pruning months: March–April.

When: In March–April, as growth starts. Pruning is not essential but gives a fuller, better-branched plant.

How:

• Cut back over-long branches to just above a node; several new branches usually grow from below the cut.
• Use a sharp, clean knife or secateurs and wear gloves.
• Let the wounds dry and water less for the following week.
• Use healthy tips you have cut off as cuttings.

Caution: The milky sap is highly toxic and irritates skin and eyes. Wear gloves, do not rub your eyes, and wash your hands and tools after pruning.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Seed

Fresh seed germinates readily at 25–30 °C, laid on the surface of moist seed compost. Seedlings soon form a thick caudex.

Cuttings

In summer, cut tips 10–15 cm long, let them dry for a few days and insert them in dry, sandy compost in a warm place. Plants grown from cuttings form a less swollen caudex.

Desert rose: how does it get through the winter?

• Keep it indoors in a bright spot, never below 12 °C: cold combined with wet compost is fatal.
• In winter it rests and often loses some or all of its leaves: that is normal.
• Then give almost no water, at most a little when the caudex starts to wrinkle.
• Do not place it against a cold window or in a draught. In March, when new leaves appear, gradually give more water again.

Diseases and pests

• Caudex rot: A soft, brown or black caudex caused by too much water or cold. Cut out the rotten part back to healthy tissue, let it dry and water less.
• Leaf drop: Yellowing leaves and leaf drop in autumn are normal. In summer they point to too little light, too much water or a sudden change of position.
• Mealybugs: White, woolly tufts in the leaf axils. Remove them with a cotton bud dipped in methylated spirits.
• Red spider mite: Fine yellow speckles and webbing under the leaves in dry, warm air. Spray the leaves regularly with lukewarm water.
• No flowers: Too little sun or no winter rest. Give it the sunniest spot and let it rest dry and a little cooler in winter.

Through the year

• January: Rest. Almost no water, minimum 12 °C.
• February: Rest. Keep bright and dry.
• March: Prune and repot. Gradually give more water as growth resumes.
• April: Repot or prune. Start feeding.
• May: First flowers. Water as soon as the compost is almost dry.
• June: Move outdoors to a warm, sunny spot. Flowering.
• July: Full flower. Feed monthly. Take cuttings.
• August: Flowering. Last feed.
• September: Flowering. Bring indoors before nights turn cool.
• October: Water less. The leaves start to yellow.
• November: Rest. Dry and bright, minimum 12 °C.
• December: Rest. Almost no water.

Edible and useful

Not edible. All parts of desert rose are highly poisonous, especially the white milky sap: it contains cardiac glycosides, compounds that, like those of foxglove, act strongly on the heart, and in Africa it was used as an arrow poison. Swallowing any causes vomiting, stomach ache and diarrhoea and can seriously disturb the heart rhythm; the sap also irritates the skin and eyes. Keep the plant out of reach of children, cats and dogs, also when it spends the summer outdoors. Wear gloves when pruning, taking cuttings and repotting, keep sap out of your eyes and wash your hands and tools afterwards. Call your vet at once if an animal has eaten some. If any is swallowed, call a poison centre (in Belgium 070 245 245) or your doctor at once.

Did you know?

• In parts of Africa the milky sap was once used to poison arrowheads.
• The species name obesum means ‘fat’ or ‘plump’, after the swollen base.
• In Thailand and elsewhere in South-East Asia countless varieties are grown, with single, double and even striped flowers.