Me too!
Find the late summer/fall gentians I've planted much more dependable than the spring ones (survival and spread).
Most of mine are "gentian blue" too.
Was at Merlin's Hollow (local big garden of David and Dierdre Tomlinson) on Saturday.
Cold! See picture below; David left, Dierdre right.
Should have taken winter jacket myself.
Was talking to David who's raised many different gentians from seed and has his gentians in the same bed.
He said Gentian Acaulis Group are difficult; no problem keeping them alive, but they don't have many blooms here.
Though different gentian do favour different soil pHs, he thinks the problem is the alkalinity of our soil.
Merlin's Hollow has something like 1500 different perennials.
The scree (gravel) beds (notably spring plants) are particularly attractive at this time of year.
Below (Saturday also).
The dark purple is spring pea (Lathrys vernus).