Ph for Siberians

I got a cheapie soil test thingy from Lowes this weekend and tested my iris bed. I have TB's and Siberians. The Siberians aren't doing too well I've lost 2 or 3. I tested the soil and found it to be about a ph of 8.0. Well I'm thinking that's ok for TB's but well over for the Siberians. Trouble is, the same soil in that bed is in all of my beds. Any advice on how to amend a plot for transplant of my Siberians before I lose them all?

You can use soil sulphur to lower the ph of your soil. That might be a bit drastic for siberians though it does well for my japanese iris. Have you thought about miracid?

I'm thinking of transplanting to another area that I've amended. I will need to test the ph in that area and see if it differs.

Beardless irises love acid. Beardeds love sweet. If I mix them, one always does badly, so I tend to keep them in their own areas.