Hydrangea macrophylla

Hydrangea macrophylla, also known as bigleaf hydrangea, is a popular flowering shrub known for its large, beautiful blooms and its ability to change flower color based on soil pH. Here's a guide to understanding and caring for it:

Care Tips:

1. Light:

• Prefers partial shade.
• Avoid full afternoon sun, especially in hot climates—it can scorch the leaves.

2. Soil:

• Moist, well-draining soil is key.
• Rich in organic matter.
• Soil pH affects bloom color:
  • Acidic (pH < 6): Blue flowers
  • Alkaline (pH > 7): Pink flowers

3. Watering:

• Needs consistent moisture, especially during dry spells.
• Water deeply 1–2 times a week; more often in hot, dry weather.

4. Fertilizing:

• Use a balanced fertilizer in early spring.
• Avoid over-fertilizing; too much nitrogen can reduce blooming.

5. Pruning:

• Blooms on old wood, so prune after flowering, not in spring.
• Just remove dead or weak stems to shape the plant.

6. Winter Protection (for colder zones):

• Apply mulch around the base.
• Cover with burlap or plant in a sheltered location.

7. Pests/Diseases:

• Generally hardy, but watch for:
  • Powdery mildew
  • Aphids or spider mites
  • Leaf spots (if overly wet or crowded)

Bonus Tips:

• To change bloom color:
  • Add aluminum sulfate for blue flowers.
  • Add lime for pink flowers.
• Ideal for borders, containers, or as a showy foundation plant.