Euphorbiaceae
Euphorbia geroldii (Thornless Crown of Thorns)
Euphorbia geroldii
Give this fast-growing succulent as much bright light as possible, water thoroughly only once the soil has dried out, and pot it in a gritty, fast-draining cactus mix. It tolerates heat and coastal conditions well but is not frost-hardy and must be protected below about 10 C (50 F). Handle with gloves, since the milky latex sap is an irritant.
Every 10 days
Bright indirect
10° - 35°C
% - %
Categories
What is Thornless Crown of Thorns?
Thornless Crown of Thorns (Euphorbia geroldii) is a medium-care plant from the Euphorbiaceae family. Euphorbia geroldii, commonly known as the Thornless Crown of Thorns or Gerold's Spurge, is a succulent shrub in the spurge family (Euphorbiaceae), endemic to the dry coastal forests of northeastern Madagascar. Unlike its thorny relative Euphorbia milii, E. geroldii produces smooth, unarmed woody ste...
Thornless Crown of Thorns grows up to 2.0m, watering every 10 days, 10°C – 35°C. It is suitable for indoor environments and not safe for pets.
Without precautions, ingestion can cause irritation in pets. Keep out of reach of cats and dogs. Without adequate drainage, root rot can develop within 20 days.
How to Care for Thornless Crown of Thorns?
TLDR: Thornless Crown of Thorns needs Bright indirect, watering every 10 days, and temperatures between 10-35°C with 40-70% humidity.
How Often Should You Water Thornless Crown of Thorns?
Let the soil dry out completely between waterings, then soak thoroughly and allow excess water to drain away fully. Reduce watering to about once a month in winter when growth slows, and never let the pot sit in standing water.
How Much Light Does Thornless Crown of Thorns Need?
Provide as much bright light as possible, ideally several hours of direct morning or afternoon sun daily indoors, or a sunny to lightly shaded spot outdoors. Insufficient light causes leggy growth and fewer blooms.
What Is the Best Soil for Thornless Crown of Thorns?
Use a very well-draining mix, such as a cactus or succulent potting mix amended with extra pumice or perlite. Always plant in a container with drainage holes to prevent waterlogging and root rot.
What Pot Should You Use for Thornless Crown of Thorns?
Terracotta or unglazed clay pots with generous drainage holes work best, as they wick away excess moisture and help prevent root rot.
What Is Thornless Crown of Thorns and Where Does It Come From?
Euphorbia geroldii, commonly known as the Thornless Crown of Thorns or Gerold's Spurge, is a succulent shrub in the spurge family (Euphorbiaceae), endemic to the dry coastal forests of northeastern Madagascar. Unlike its thorny relative Euphorbia milii, E. geroldii produces smooth, unarmed woody stems clothed in glossy, dark green, lance-shaped leaves edged in red. Clusters of small, saucer-shaped bracts in vivid red with yellow centers appear almost continuously throughout the year, making this a popular, low-maintenance flowering succulent for bright indoor spaces and warm-climate gardens. In the wild it is classified as Critically Endangered due to habitat loss, so cultivated specimens play a small role in ex-situ conservation.
How to Propagate Thornless Crown of Thorns?
Stem tip cutting
Wear gloves when taking cuttings, as the milky sap is a skin irritant; rinse the cut with water to slow sap flow before letting it callus.
- 1 Cut a healthy stem tip about 10-15 cm long using clean, sharp tools.
- 2 Let the cut end callus over in a dry, shaded spot for 2-3 days to reduce rot risk from the latex sap.
- 3 Insert the callused end into a barely moist, well-draining succulent mix.
- 4 Keep in bright, indirect light and water sparingly until roots establish, then resume normal watering.
Materials needed:
How Big Does Thornless Crown of Thorns Grow?
TLDR: Thornless Crown of Thorns can reach up to 2.0m tall with Fast growth rate.
Max height
2.0m
Growth rate
Fast
Foliage
Evergreen
Warning: Toxic Plant
This plant can be toxic if ingested. Keep out of reach of:
Plant Uses
Ornamental
Great for decoration
Is your plant showing symptoms?
Click on the symptom to discover possible causes:
What Diseases Commonly Affect Thornless Crown of Thorns?
TLDR: Thornless Crown of Thorns is susceptible to 8 known diseases. Monitor regularly for early detection.
Root Rot
Root rot is a serious fungal disease that affects the root system of plants, causing them to decay and die. It is primarily caused by overwatering, poor drainage, or soil-borne fungi such as Pythium, Phytophthora, Rhizoctonia, and Fusarium. The disease thrives in waterlogged conditions where roots are deprived of oxygen, making them susceptible to fungal infection.
Mealybugs
Mealybugs are small, soft-bodied insects covered with a white, waxy, cottony material. They are common pests of houseplants and outdoor plants in mild climates. These sap-sucking insects feed on plant tissue, causing damage, stunted growth, and can lead to plant death if left untreated. They produce sticky honeydew which attracts sooty mold.
Spider Mites
Spider mites are tiny arachnids (less than 1/20 inch long) related to spiders and ticks that feed on plant sap. They thrive in hot, dry conditions and can cause significant damage to ornamental and vegetable plants. During severe infestations, crop losses can reach 14% or higher as these pests disrupt vital plant processes including photosynthesis, carbon dioxide absorption, and transpiration.
Aphids
Aphids are small, soft-bodied, pear-shaped insects (1/16 to 1/8 inch long) that feed by sucking nutrient-rich sap from plants. They reproduce rapidly and can quickly weaken plants, causing distorted growth and transmitting plant viruses. Aphids come in various colors including green, black, red, yellow, brown, and gray. They secrete honeydew, a sticky substance that attracts ants and encourages sooty mold growth.
Fun Facts
Despite resembling a miniature tree, Euphorbia geroldii is a true succulent that stores water in its thick stems.
It is endemic to Madagascar and is classified as Critically Endangered in the wild.
Unlike the popular crown of thorns (Euphorbia milii), this species has no spines at all.
Its colorful red-and-yellow flowers are actually bracts surrounding tiny true flowers, a hallmark of the Euphorbia genus.
Frequently asked questions
Is Euphorbia geroldii the same as crown of thorns?
Is Euphorbia geroldii toxic?
How much light does it need?
How do I propagate it?
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