[4seasons]

Looking at the picture that Agla posted, there are some hydrangeas but w/ different colors. I heard of different ways to change from blue to pink-- or vice versa. What are some of the ways you guys and girls go about doing it? What is the time frame associated with each variable.

[agla]

Aluminum sulfate turns those that vary to blue. Lime turns them pink.

I believe that it isactually the Al that affects the color, but lack of acidity binds up the aluminum. We have naturally high amounts of Al here and acidic rain, so we usually don't need an effort to get some really nice blues.

Not all hydrangeas do this.

Some guys put a little lime and a little Aluminum sulfate in patches around the plants to get them to vary on the same plant.

[TrickyDick]

There are a lot of myths out there about this. Agla is right about the why and how. The other important part of the equation is to plant the color you want. If you want blue plant a blue. If you have alkaline soil you may need to add aluminum sulfate periodically to get a nice blue but life will be easier if you don't plant Pink Beauty and try to make it look like nikko blue, or vice versa.

[4seasons]

I planted endless summer for the job in question. So they can go either way. How is the time frame on coloring, I was going to add Al Sulfate in the spring when we mulch. Or should I wait longer closer to blooming time?

[TrickyDick]

It depends what the soil pH is now. If it is high you may have to add it as directed on the label (you can add too much and kill the plants) every few months to slowly bring the pH down to 5 or 5.5 and then continue to add it a couple of times a year to keep it down. If your pH is low you probably don't have to do anything. Mulching with pine needles or peat moss will help too.

Have you tested the soil? Why do you think you need to adjust the pH?

[4seasons]

no I haven't tested it yet. I just want to be ready, and know what to do.
She wondered if we could make them all blue, we just planted last summer.
When we planted they were a mix on each bloom. I asked last year if she wanted all blue,cause I would have planted nikko's instead-- but she said it didn't matter. Probably saw a picture in a magazine. I'm meeting w/ her to discuss future projects so I'll see about a test then.

[TrickyDick]

A lot of times container grown hydrangeas can be more pink because of the potting soil. You really do need to test or wait and see what they do because the difference between blue and pink is about one point of pH.