What’s the problem?
My African milk tree has started growing tall and spindly, with a lighter green colour.
Diagnosis
Your African milk tree (Euphorbia trigona) has become “leggy” due to insufficient sunlight. This succulent originates from west Africa, where it thrives in bright, indirect light and is adapted to arid environments. The technical term for this issue is etiolation – when a plant doesn’t receive enough light, it stretches towards the light source, resulting in elongated growth and paler colouring as it tries to maximise photosynthesis.
Prescription
While you can’t undo the leggy growth, you can stop it from getting worse by moving your plant closer to a south-facing window where it can bask in bright, indirect sunlight. If the leggy look bothers you aesthetically, you can prune the elongated parts.
Prevention
Regularly rotate your plant to ensure even exposure to light. Monitor its growth and tweak its position as light levels shift with the seasons. Look out for rich green colour in new growth; this means your plant is getting the right amount of light.
Got a plant dilemma? Email saturday@theguardian.com with ‘Houseplant clinic’ in the subject line
• This article was amended on 20 January 2025. An earlier headline incorrectly described the plant as a cactus.
