How do I get a hydrangea bush to be purple?? I know to use lime for pink color, but how do I get purple?

To get the pH of the soil slightly lower than it is at the moment. Strong Alkali makes the hydrangea go blue and with the lime you have made it more acidic so it needs to be slightly less acidic but not too acidc for pink as you have them already. It may take a bit of time to get the right coulour.

How do I get a hydrangea bush to be purple?? I know to use lime for pink color, but how do I get purple?
There are a lot of myths about PH being a factor - but the PH just affects the absorption of Aluminum by the plant in this case. Hydrangeas with Aluminum and acidic soil will be blue - but they need both, which is why Aluminum Sulphate is the proper additive. You can buy it at the garden store and they even sometimes sell it as "Hydrangea Blueing Additive" - but it is just plain old Aluminum Sulphate. Wash your hands after handling or wear gloves to apply it around the base of the plant. It is most effective when applied before the leaves start to come out, but it will eventually make the later blooms more blue (or purple) even if it is already blooming now.
Reply:I have heard to enhance blue and purple colors you need to add iron to the soil. This could be baloney - but my Grandma once told me that they used to hammer an iron nail into the base of the bush to make it really blue. I've never tried this and I don't know if it would work - but I've heard it from other sources too.





The ph of the oil will also enhance the color. so you may want to try adding iron that way first so you don't kill your bush!
Reply:Appears to be an aluminum additive, but the PH level of your soil plays a role in what gets absorbed into the plant. See the article attached.





http://edis.ifas.ufl.edu/EP330
Reply:Go to a gardening center and ask them what to put in the soil to make them purple.
Reply:you have to just mess around with the pH of the soil, which is what determines the flower colour.
Reply:...grape juice concentrate