Question
We live in Richmond Virginia.  What type of fertiziler do you use to produce blue blooms?  We have had them in the past but this year they were white, then changing to a brownish color.

Answer
Some hydrangeas are naturally white and will not change color in response to soil pH. E.g. Hydrangea "Annabelle" or Hydrangea "Snow Queen".

Other hydranges, such as the mopheads (Hydrangea Macrophylla) will change color of their blooms according to soil pH. Usually blue in acidic soils (low pH) and pink in sweet (alkaline) soils (high pH).

You can buy some "Gardeners Sulphur" in 5 lbs bags at a garden center. Spread this LIGHTLY (L-I-G-H-T-L-Y) as a fine dusting every few weeks over the next season to lower the soil pH. Do not spread too much too quickly or your risk chocking the plant. Sulphur will lower the soil pH.

You can also use fertilizers which are based on acidifying elements, such as Miracle Grow's cousin: MIRACID (30-10-10). Another excellent - organic - version is ESPOMA's "HOLLY TONE". However, for fastest and most consistent response, use Sulphur to lower the soil pH.

I don't know which Hydrangea you have in your yard, but typically white flowering varieties can not be made to flower blue.