Decode red/purple stress colors and use them (safely) as ID clues.
Why leaves redden
Bright light, cool nights, and drought can trigger anthocyanins that turn leaves red, purple, or bronze, especially at tips and margins.
Use color for ID
Sedum rubrotinctum reddens strongly; Aeonium arboreum darkens in sun/cool; many Echeveria blush at edges.
Care caution
Color should not come from scorch—if patches turn crispy, step back from intense midday sun.
