That's strange Daisy because it acts as an annual for me. The plants die back in the summer and have never come back in the same place.
I'll have to see if the blue flowers eventually turn pink Sue. This is my first year seeing them. But all the plants have purple buds. Some just open to pink and the one to blue. The first two years the flower started off blue or purple but in a day changed to pink.
I'm not sure about adding aluminum sulphate cwhitt. I have them next to daylilies, lilies and crocosmia and I'm not sure how that would impact the other plants.
I guess I'll have to stop giving the seeds away in swaps saying the flowers are going to be pink! I'm tempted to try and dig up and pot a pink one and keep it inside to try and keep the color. I'm just not sure how well they would do indoors.
Thanks for the great advice everyone!