Marietta Daisies Garden Club

Hydrangea macrophylla (Bigleaf Hydrangea)

are popular deciduous shrubs known for massive, summer-blooming flower clusters in blue, pink, or white, thriving in partial sun and moist, well-drained soil.

Key Care and Growing Conditions

• Light: Part sun is best, ideally with morning sun and afternoon shade.

• Water: Keep soil consistently moist but not waterlogged.

• Soil: Rich, porous, well-drained soil is essential.

• Color Control: To get blue flowers, lower the soil pH by adding aluminum sulfate. To get pink flowers, raise the pH by adding lime.

• Fertilizing: Feed in spring and early summer; stop after mid-August to allow growth to harden off.

Common Problems

• No Blooms: Often caused by improper pruning (pruning too late, as they bloom on old wood) or, in colder climates, by late winter frosts killing the flower buds.

• Wilting: These plants (name means "water vessel") need constant moisture, especially in high heat.

• Leaf Spot/Powdery Mildew: Can occur in humid conditions.

Pruning and Maintenance

• When to Prune: Prune Hydrangea macrophylla in summer, immediately after the flowers fade, as they set next year's buds on old wood.

• Winter Care: In cold climates, protect the shrub's base with 18 inches of mulch to protect buds for the following year.