Yellowing and Scaly Outdoor Cacti: Diagnosis Checklist

Naomi's two large outdoor cacti declined after blooming: one yellowed, the other developed scaly edges. The expert needed more info to distinguish cactus from succulent and pinpoint causes.

Key Questions for Diagnosis

1. Spine arrangement: pairs along edges (typical cactus) or clusters from fuzzy areoles?
2. Are yellow areas soft/mushy (rot) or firm (sunburn/corking)?
3. Do scaly patches peel off easily (scale insects) or are they part of the skin?

Common Causes

• Yellowing: overwatering, poor drainage, nutrient deficiency, or post-bloom exhaustion.
• Scaly edges: scale insects, fungal lesions, or natural corking with age.

Next Step

Email photos to gregandkat@msn.com for precise ID and treatment plan.