
Alkaline soil means hydrangeas are Pink,
Acid soil means hydrangeas are Blue :) :)
Good way of finding out your soil type without using kit!!!
So if you want Blue hydrangeas and have alkaline soil, you need to treat them as you would Rhodedenrons, Azaleas etc. Plant them IN TUBS in ericasious compost and only water with rain water. If you have to water them with tap water you use a special azalea etc feed of sequescence of iron!!!!
As for whites, I presume it is in neutral soil but I am not 100% sure, I just know I have never seen white hydrangeas in gardens!!! LOL
HTH
Lea :)