What determines the color of hydrangea flowers?
Hydrangea grow in many of the gardens in Theodore Roosevelt Park. Their colors range from indigo blue to purple to bright pink. Hydrangea macrophylla, a plant that is native to China and Japan, produces different colored flowers depending on the soil pH.
Acidic or alkaline soil
When the soil is acidic, meaning the pH is below 7, Hydrangea macrophylla produces flowers that are closer to blue. Hydrangea growing in alkaline soil (pH above 7) produce flowers in the pink and lilac color range.
Hydrangea Macrophylla will bloom until late autumn, and they can grow six feet tall. These plants can do well in full sun or partial shade. Look for these beautiful flowers in our gardens at the 81st Street side of the park, near Central Park West and Columbus Avenue, and in front of the Hayden Planetarium and the Bull Moose dog run.