Reviving Yellowing Hydrangeas in Clay Soil

Yellow leaves and color shift from blue to pink on mophead hydrangeas often signal high soil pH and low organic matter in clay soils.

Diagnosis

• Test soil pH – hydrangeas need 5.0–5.5 for blue flowers.
• Check drainage – clay holds water, causing root stress.

Treatment Plan

1. Amend with peat moss or pine bark to lower pH and improve structure.
2. Fertilize with a product for acid-loving plants (high nitrogen, with sulfur).
3. Mulch with pine needles or shredded oak leaves.
4. Water deeply but infrequently to avoid waterlogging.

Retest pH annually and adjust as needed.