Succulent Euphorbia are flowering plants in the Euphorbiaceae, not true cacti. Convergent evolution has produced ribbed, columnar and globular forms that resemble cacti, but their flowers, tissues and milky latex are different.
This guide covers tender collector species grown indoors or under glass in the UK. For available plants, visit the Cacti & Succulents collection.
Light
Provide a bright position and introduce direct sunlight gradually. Insufficient light can produce weak or distorted growth, while a sudden move from protected conditions into intense sun can scorch stems. Highly variegated plants need enough light to support their limited green tissue but their pale areas are also more vulnerable to damage.
Watering
Water according to active growth, temperature, root condition and drying rate rather than a rigid calendar. Saturate the root ball, allow water to drain and do not leave the pot standing in water. Wait until the mix has dried before watering again. During cool, low-light UK winters, water much less frequently because slow water use increases the risk of stem and root rot.
Substrate and pots
Use a stable, sharply draining mix with persistent air spaces. A combination of peat-free organic material and mineral particles can work well, but particle size and pot depth matter more than a branded recipe. Pots must have drainage holes. Terracotta dries faster than plastic and may suit cool or humid rooms, while small plastic pots can be useful where plants dry too quickly.
Temperature and ventilation
Most tender succulent Euphorbia should be kept frost-free. A practical minimum for the collector plants covered here is around 10°C, with warmer conditions preferred during active growth. Avoid the combination of low temperature and wet substrate. Gentle ventilation helps moisture evaporate and reduces persistently humid conditions around the stem.
Feeding and repotting
Feed lightly during active growth with a dilute, low-nitrogen fertiliser. Repot when roots have filled the pot, the substrate has broken down or the plant has become unstable. Do not automatically overpot: a large volume of wet mix around a small root system can remain damp for too long.
Pests and problems
Inspect ribs, growing points and roots for mealybugs. Soft, dark or translucent tissue can indicate rot, especially after cold or prolonged moisture. Wrinkling can reflect thirst, root loss or seasonal rest, so check the root zone before simply adding more water.
Latex safety
All Euphorbia should be handled as irritant plants. Their white latex can damage skin and eyes and is harmful if ingested. Wear gloves when cutting or repotting, avoid touching your face and wash tools after use.