Clerodendrum myricoides (Butterfly Bush) Not Blooming: Climate & Care Check

Clerodendrum myricoides (Blue Butterfly Bush) is tropical/subtropical (Zone 9b+). Rancho Bernardo (San Diego inland) is borderline Zone 9b/10a—should bloom with proper care.

Why No Flowers?

• Insufficient heat units: Needs long, hot summers. Cool coastal influence delays bloom.
• Over-fertilization (Nitrogen): Lush leaves, no flowers. Use bloom booster (high P, low N).
• Pruning at wrong time: Blooms on new wood. Prune late winter/early spring only.
• Inadequate sun: Requires 6+ hrs direct sun.
• Water stress: Consistent moisture during bud set.

Action Plan

1. Confirm microclimate: USDA zone, heat days, frost dates.
2. Soil test; adjust pH to 6.0–6.5.
3. Switch to 5-10-5 or 10-30-10 fertilizer March–Sept.
4. Prune hard in February (to 12–18").
5. Ensure full sun exposure (thin overhead branches if needed).

Research

Google "Clerodendrum myricoides care" for university extensions (UF, TAMU, UH) and forums (GardenWeb, Dave's Garden).

This plant can bloom in your area—dial in the culture.