Question: I received a pretty blue flowering hydrangea for Mother’s Day. I already have white-flowering hydrangeas that I would like to turn blue. I was told I could put nails in the soil around the roots to turn them blue. Is that true, and if so, what kind of nails do you use?
Answer: It is not true that nails or pennies should be put in the soil around plants for any reason. They will not help the hydrangea have blue flowers.
There are two species of hydrangeas that can have blue flowers. Hydrangea macrophylla (bigleaf hydrangea) is native to the coastal areas of Japan. Hydrangea serrata (mountain hydrangea) is native to the mountainous areas of Japan but is much less common in the U.S. than the big-leaf hydrangea. They are so similar that some people think they are one species, but the mountain hydrangea has hardier flower buds and can bloom better in the northern states….