Mottled spurge (Euphorbia lactea) is a spurge species native to tropical Asia, particularly in India. Mottled spurge is commonly planted as an ornamental species in tropical regions and grown as a houseplant in temperate regions. This species is also commonly known as dragon bones and is highly toxic if consumed.
I. Appearance and Characteristics
Euphorbia lactea is a species of spurge native to tropical Asia, mainly in India.
It is an erect shrub growing up to 5 metres (16 ft) tall, with succulent branches 3–5 centimetres (1.2–2.0 in) diameter, ridged, with a triangular or rhombic cross-section; the ridges are spiny, with short spines up to 5 millimetres (0.20 in) long. The leaves are minute, and soon deciduous. All parts of the plant contain a poisonous milky latex. Common names include mottled spurge, frilled fan, elkhorn, candelabra spurge, candelabrum tree, candelabra cactus, candelabra plant, dragon bones, false cactus, hatrack cactus, milkstripe euphorbia, mottled candlestick.
Mottled candlestick is entirely poisonous, from root to sap. If you have curious pets or children, this is not the plant for you. Be cautious when handling crested cactus. The toxic sap, called latex, will ooze from stem cuts and can irritate your skin. Gardeners should always wear gloves when handling E. lactea.
II. How to Grow and Care
Sunlight and emperature
Full to partial sun is ideal for mottled spurge. Be cautious placing it in full sun though. When exposed to direct light and heat, it can easily sunburn. It can also be burned if exposed to bright light suddenly. When moving your mottled spurge, do so gradually so it can acclimate.
Euphorbia lactea cannot handle frost! 40° F is the lowest temperature this plant may tolerate. This shrub grows best when it’s warm, so we recommend not testing lower temperatures.
Watering and Humidity
False cactus responds well to the ”soak and dry” method, with a few exceptions. For this method, soak the soil until water leaks out of the drainage hole. Let the soil dry out completely before watering again. Because it comes from a tropical climate, false cactus handles humidity well.
During the summer, water your Euphorbia lactea at least once a week. Alternately, drastically cut down on water during the winter. Only water it once or not at all during this time.
Because of its varying water demands, you should know how to tell if your false cactus needs more or less water. When overwatered, it will turn yellow, brown, and mushy. If left unchecked, the messiness can quickly turn to rot. Underwatered false cactus will begin to wrinkle and wilt. This plant will bounce back faster when underwater than overwatered.
Soil
The soil needed for dragon bones is typical for any cactus or succulent. It has to be well-draining so that your plant is never sitting in water. This is vital to keeping it alive.
There are many soils out there made specifically for succulents and cacti. If you already have the materials though, you can mix your own well-draining soil. Just add one part perlite or sand to one part potting soil. After planting, regularly check that the soil is draining well and make adjustments as needed.
Fertilizing
Give your mottled spurge half-strength fertilizer every month from spring to fall. This will give it an extra boost for the growing season. Fertilizer low in nitrogen will provide the best results.
The roots of mottled spurge can sometimes be burned by fertilizer. To prevent this, dilute your liquid fertilizer to ½ or ¼ strength and apply it right before watering.
Pruning
Mottled spurge rarely requires pruning. The only time it’s necessary is if part of the plant is rotting or otherwise injured. Simply cut back the damaged parts with a clean knife. The plant will heal by itself as long as you keep the cut section dry.
Propagation
When it comes to propagation by cuttings, you’ll have the best luck with the basic Euphorbia lactea. The crested and variegated forms don’t root well, so they’re often propagated by grafting. Before getting started on either, remember to cover up! You’ll be cutting into the plant, so toxic sap will definitely be present.
Take your cutting during the spring or summer, when your mottled spurge is growing the most. Using a sharp, sterile knife, slice off one of the arms where it connects to the stem. If you encounter a flow of sap here, wash it away with cold water.
After taking your cutting, dip it in rooting powder and let it dry out for a week to two weeks. Once the cut is calloused over, stick your cutting upright in the soil. Mist the soil with water or leave it dry until the roots are established. Euphorbia lactea roots best in heat, so place it outside or on a heating mat.
Grafting
It’s a complicated process, but if you want to make yourself a coral cactus from your Euphorbia lactea, you’ll have to graft it to a Euphorbia neriifolia. Here’s how to do it:
- Choose an E. lactea cutting and Euphorbia neriifolia that are young and healthy and which look like they’ll fit together.
- Cut a V in the neriifolia, removing the upper portion to make the base of the plant.
- Cut a matching V in the lactea that will fit exactly into the neriifolia.
- Piece together the two V cuts with lactea on top. Check that there aren’t any gaps between the two, which can lead to rot.
- Seal the V with grafting wax.
- Wrap the whole graft in twine.
- Wait 2-3 weeks for the plants to heal and then remove the twine.
- Enjoy your new Frankenstein cactus!
Repotting
When you buy it, your Euphorbia cactus will probably come in a small container and general garden-store soil. You’ll need to repot it into something bigger and better draining. Choose a container that’s about two inches larger in diameter and is heavy enough to balance out the height of your E. lactea. You don’t want it to become top-heavy and fall over.
For such a tall plant, dragon bones has small roots. This gives it the benefit of rarely being rootbound. When you remove it from the pot, gently dust off the roots and massage them out if they’re clumped together. Repot it in dry, well-draining cactus soil. It may be tempting to treat your dragon bones to a drink, but hold off on the water for a couple weeks. This will give the roots time to heal from any damage.
Because of its spines and toxic sap, safety is your top priority when repotting. Remember to always, always wear gloves! For added protection, cover your arms and legs and wear safety goggles – especially if you’re repotting a large Euphorbia lactea. If your plant has multiple stems growing close together, protect them from each other by padding them with newspaper before moving.
Pests and Diseases
- Common Pests
Mealybugs are a common pest that are always hungry for succulent sap. These scale insects are small and build cottony white nests. Infestations will cause the plant to turn yellow, wilt, and eventually die.
Remove mealybugs by dabbing them with a q-tip dipped in diluted rubbing alcohol (70% or lower). Insecticidal soap is a common remedy for mealybugs, but not recommended for Euphorbia lactea as it can damage the plant.
Spider mites may also appear on your mottled spurge. These are exceptionally tiny arachnids that make small webs on plants. Wash them away with a strong spray of water. Alternatively, apply thoroughly diluted neem oil to the stem.
- Common Diseases
Powdery mildew looks exactly how it sounds: white and moldy. Dragon bones is prone to it when there’s poor air circulation and humidity. Like every disease, it’s best eradicated early on. To remove powdery mildew without damaging your plant, wash the plant with a baking soda mixture. Dissolve one tablespoon of baking soda into a gallon of water for the perfect mildew remedy.
The most common threat to succulent-like plants is root rot. Even though it usually starts in the roots, any part of your Euphorbia lactea can fall victim to this condition. Rot begins when the plant is constantly wet – a result of overwatering and/or poor drainage. Rotted sections will become brownish-black and mushy.
If you notice even the smallest amount of rot, you’ll need to take action right away. If left to spread, the entire plant can quickly die.
Remove your plant from its container so you can examine the whole thing. Carefully cut off any parts that are rotted. Once the plant is rot-free, leave it out of the soil to dry for several days. Once the wounds have scabbed over, replant your Dragon Bones in new soil.
III. Uses and Benefits
It is used medicinally in India. It is widely grown as an ornamental plant, both in the tropics, and as a houseplant in temperate regions; a number of cultivars have been selected for ornamental use, notably ‘Cristata’ with frilled branching.
