Why One Hydrangea Blooms Sparsely While Others Thrive

A large hydrangea has only two blooms in two years, despite Ironite applications. Other hydrangeas nearby bloom heavily. The gardener wants to increase flowering.

Troubleshooting Checklist

• Light exposure: Compare sun hours. Hydrangeas need morning sun/afternoon shade. Too much shade = few flowers.
• Pruning timing: If it's a macrophylla (bigleaf), it blooms on old wood. Pruning in fall/winter/spring removes buds.
• Winter damage: This plant may be in a colder microclimate (frost pocket, wind exposure) killing buds.
• Soil nutrition: Ironite supplies iron, not phosphorus. Use a bloom booster (high P) like 5-10-5 or 10-20-10 in early spring.
• Root competition: Nearby trees may be stealing water/nutrients.
• Soil pH: Test pH; macrophylla color and health depend on it.

Systematic Approach

1. Verify variety and prune correctly (or not at all).
2. Soil test for pH, P, K.
3. Apply high-phosphorus fertilizer in early spring.
4. Ensure consistent moisture (not wet).
5. If no improvement in one season, consider relocation.

Trial and error with these factors will reveal the cause.