"I've noticed that some of the blades are turning reddish tan, similar to BBS's fall color. Is this normal? Do you think I ought to divide and transplant these now directly into the garden?"

yes

No, a strong frost (still likely in southern MI) could really set these tender little plants back. I'd wait until May.

But try to keep the seedlings in the sun. The reddish color is probably a result of shading.

Thanks to both of you for responding. Looks like I'll be dividing and transplanting to pots and moving them to the greenhouse.

I am not very experienced, but I disagree that the seedlings will be harmed by frost, unless I am not reading your post correctly. Were they grown inside or outside in the saucers?
I have grown BBS seedlings this year using the winter sowing method- outside in recycled milk jug containers and they are not susceptible to frost. I am jealous because mine have only just sprouted and are not 3 inches high.
Now I think yours must be inside if they are that large and should be hardened off before being planted out.
It was very easy to grow them outside because I just planted them and forgot about them pretty much, just making sure they were moist.
Good luck with your bluestem!

I wintersowed some too and they are way small in comparison to the one I started indoors at 4-6" clumps...they too started getting that fall color...these went out last weekend and getting 30+night temps they have greened up again.

I've made a boo boo though...I wintersowed both BBS/LBS for the meadow area bed and Blue fescue for my rock garden bed by the front deck and all the wimpy ID tags either vanished or disinigrated.....and I can't tell which ones are which on those...guess I'll be waiting a while before those go in the ground! LOL!

Vera

oogy4plants, I started the seeds indoors and placed them on a table in front of a south-facing window. Last weekend, I divided up the big clump into 8 or 9 individual clumps, and planted each in 4-inch plastic pots. They now occupy a shelf in our unheated greenhouse (daytime greenhouse temps hover around 70+ degrees). Our nights are still on the cold side, so I'll gradually move these pots outside to harden off before planting permanently in the ground. My main concern right now is keeping them from drying out. I figure I have better control of that while they're in pots rather than losing them in the garden by August.

Seedlings grown indoors and this young could indeed be harmed by frost. In nature they don't germinate until average soil temperature reaaches the sixties and then have a whole growing season to get established. The reddish coloring is most likely due to the stress of crowding, so good idea to divide and re-pot until danger of frost is past.

update on the hardend-off indoor plugs I transplanted outside...
They are now getting that 'fall' color, but other than that are just fine....our warmer weather is arriving tomorrow and steadly climbing thereafter!
Festuca ovina doing well too..

My mother in NDak. wintersowed lots of plugs of both LBS and BBS and in one season the BBS towered over her 5'2" and the LBS was knee high...

Vera