Question
My Hydrangas have lots of flowers but they are green with just a hint of pink.  I would like them to be blue or pink. What type of fertilizer do I need to use?  I can't remember if the soil needs need to be acidic or alkaline.  I live in Southern California, and you probably know it is hot here. My plants face north are about 2-3 years old and are about four feet tall .  Thank you for any help you can give me.

Answer
Donna,
Have your soil tested. You will need to adjust the soil PH to between 5.0 to 5.5 for blue flowers and 6.0 to 6.5 for pink flowers. Also fertilize the plants with fertilizer that contain the micro nutrient aluminum. This is the micro nutrient that causes the coloration in the flowers.
Good luck.
Ed Gulliksen