Petunia Yellow Leaves: Four Causes and Targeted Fixes

Yellowing petunia leaves with blooms ongoing = four distinct possibilities.

Diagnostic Checklist

1. Overwatering: Most annuals want deep soak every 4-5 days, not daily
2. Underwatering: Periodic drought = shed unsupported leaves (yellow → drop)
3. Natural aging: Lower/older leaves only, new growth fine = normal
4. Insufficient sun: Need 5+ hours direct including noon

Fertilizer Note

Slow-release 10-16-10 at planting is fine. Supplement with liquid feed early August—heat accelerates release.

Maintenance Reminders

• Wave/Supertunias: No deadheading needed
• Traditional: Deadhead by cutting stem below spent flower
• All: Weekly trim 2-3 stems by half from late June for bushiness

Consistent moisture (not wet, not bone dry) + full sun = green leaves, maximum blooms.