I have stokesia alba (white)for postage if you like. These are from 2010 and there are about 150 of them. I grow several other varieties but they won't have seeds for several months

daisy_lee - would you trade the Stokes aster seeds for Happy Returns daylily seeds? LMK

Rotting roots are obvious on most of the plants. Just dig one up and see what is going on. If the roots are more or less fine, replant it another place(roots need air to thrive. If you fill all available space with water, they will suffocate). You can also shorten the shoots a little to see if it helps for the habit.

Druse (his suggestions are usually for fresh seed) doesn't think they need cold. "Sow @70F for germination in 20-30 days". Are your seeds fresh from this season? Clothiers (with recommendation often for seed that has been dried and stored) has more of a 'flip a coin' approach....they may or may not need cold. "Stokesia laevis , Sow at 68ºF, if no germination in 3-4 wks, move to 24-39ºF indefinitely"