The mood ring of the flower world

Hydrangeas are up there with my favorite flowers in Japan, and part of that is probably because they come in such a fun variety of colors. For the pinks/purples/blues, that all comes down to the pH level of the soil, which I think is such a cool little fact. 

With acidic soil (pH below 6), hydrangea blooms tend to be blue or purple. This is because acidic conditions allow aluminum in the soil to be more available to the plant, which results in blue pigmentation.

However, when you have neutral to alkaline soil (pH above 6-7), the blooms lean towards pink or red. In alkaline soils, aluminum is less available, so the flowers develop pink hues instead.