Ask The Expert: This is the first time I've tried to grow hydrangeas in pots; they are actually doing very well. My first plant was purple that I bought in April, the color now is a greenish color, (very beautiful color). I also have a light pink (called white spirit) and burgundy color. How do I keep the color purple, pink or even blue? What plant food is best, and anything else that keeps my hydrangeas beautiful in pots. Thank You for your help in this matter. -Juanita Flower Shop Network Plant Expert Reply: Juanita, Eventually you will need to re-plant the hydrangeas in the ground. I am assuming that you have Mophead hydrangeas (Hydrangea macrophylla). These types of hydrangea bloom-colors are controlled by soil conditions, specifically the pH of the soil. To keep a hydrangea pink you would amend the soil with lime. To keep it blue you would use aluminum sulfate. Purple blooms are usually the result of a more neutral soil pH. This would be done in late [...]