With SS and VS sometimes they have to establish before a good color change is possible. On my VS I got no color change for a couple of seasons and now they look great. Thus, I would give them more time. Also apply 3 inches of mulch in spring to help maintain even moisture.

Thanks guyground, I suspected that but wanted a confirmation.

Wait for the plant to become established. That means for it to develop a much larger root system so give it 1-3 years. Also, be aware that on some years, weather may affect the results (for example, both may have issues if evening temps are not cool, etc). Over here, they always go white to brown because they bloom when our temps are in the 100s daily. I got to see some pink once (not the magenta) in a single bloom but it was for a few days and then it browned out.

presuming you did not bare root it ... it needs time to grow out of the media.. into native soil ... and that MIGHT be when it settles into expectations ...

ken