Question
QUESTION: I have read that roses like the PH of the soil on acidic side, around 6.
Are there any chemicals to help to drop PH of the soil?
Currently I have it 7.2



ANSWER: Most roses are very tolerant in regards to soil. But if you want to change the PH then lime application would be the best. There is a pelleted lime called Dolopril and this is the easiest way to do it as the other powdery type  is really messy especially on a windy day. Dolopril will cover about 500 square feet with 22 pounds. I usually just use a cup and scatter it in a 2 foot circle all around a rose bush. Hope this helps.

---------- FOLLOW-UP ----------

QUESTION: Just to confirm - I need to make PH lower. Will the "lime"
make the soil more acidic?
Thank you.

Answer
Just to clarify. You want to make the soil less acid in other words you want to sweeten the soil for roses. To drop or lower the acidity in soil you need to use something that neutralizes the acid in it. Like Tums when you get too much acid in the stomach! Here is a good explanation on how to go about it for you.
http://hgic.clemson.edu/factsheets/HGIC1650.htm