Sunburn / Stem Scorch
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About this condition
Sunburn and stem scorch occur when the surface tissue of leaves, stems, or the caudex is damaged by intense direct sunlight or a sudden change in light exposure. Plants moved from indoors to outdoors without adequate acclimatization are particularly vulnerable to summer sun.
Common symptoms
- White or brown bleached patches and scorched marks appear on leaf surfaces
- The surface of the caudex or stem turns white to cream-colored and dries out and hardens
- Affected areas develop a dry, slightly sunken texture
- Symptoms progress rapidly within a few days after exposure to intense light
Common causes
- Moving plants from dim indoor conditions directly into intense summer sunlight without acclimatization
- Intense light and high temperatures in summer (especially under south-facing eaves or in greenhouses)
- Concentrated heat from sunlight focused through glass
- Rising pot surface temperatures exposing the caudex to excessive heat
Prevention (growing conditions & routine care)
When moving plants outdoors, gradually acclimate them to sunlight over approximately two weeks by slowly increasing light exposure. Use shade cloth (30–50% shade) in summer to protect against intense direct sunlight, especially around midday. Avoid direct sunlight through glass and maintain plants in a well-ventilated location.
Related guide
→ Browse the species guide for this animalWhen to see a vet
Monitor; consult a specialist if it worsensWhat can a nursery or grower do?
Consulting a specialty nursery or experienced grower for an assessment of sunburn severity and guidance on future light management can provide tailored advice on appropriate growing conditions for the specific caudex species.
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