Why do hydrangea flowers turn green. How do you turn back pink?

Answer 1

According to this article I found it depends on the pH of the soil. I personally like the green flowers which turn a light pink as they mature. However, my hydrangea is not a florist hydrangea and yours may not be either, but I think it still holds true about the pH. The article asserts that, "Hydrangea macrophylla -- Hortensia or Florist Hydrangea This is a commonly grown hydrangea with large globe-shaped flowers. It is frequently forced by florists and sold as an indoor pot plant during the spring season. Once moved outdoors, however, color is dependent upon the pH of the soil in which it is grown: blue if acid; pink if alkaline".
Here is the full article:
http://www.uri.edu/ce/factsheets/sheets/hydrangea.html

Try feeding it an acidic fertilizer for Camellias, Rhododendrons, or Azaleas.

Answer 2

There are some varieties that naturally have green flowers (they may be classified as white). The level of acid and aluminium in the soil determines whether coloured varieties are pink or blue and how strong that colour is. The white ones' colour can't be changed as far as I know. Also, it can take a full year before transplanted plants show their true flower colour.

Answer 3

In most species the flowers are white, but in some species (notably H. macrophylla), can be blue, red, pink, or purple. In these species the exact colour often depends on the pH of the soil; acidic soils produce blue flowers, neutral soils produce very pale cream petals, and alkaline soils results in pink or purple.
In most species the flowers are white, but in some species (notably H. macrophylla), can be blue, red, pink, or purple. In these species the exact colour often depends on the pH of the soil; acidic soils produce blue flowers, neutral soils produce very pale cream petals, and alkaline soils results in pink or purple.

Answer 4

Add lime to the dirt around the plant.

Answer 5

amend the soil