Donn,
Sorry about the plants BUT they will probably be just fine if the roots are good. I have just come back from the 'special' annual plant sale that I attend with 32 pots of grasses (and assorted other perennials). These are in larger pots than your plugs but they are VERY ratty looking on the topside and terribly pot bound on the bottom side. I have had a good 85% success rate with these end of the season plants in the past.
End of pep talk, on to suggestions:
Since you are in zone 7 and still have quite a bit of good weather left. Soil temperature rather than air temperature is the important factor in this case.
- I would 'unpot' and plant out all the grasses that you recieved AND I would do it right away. You wouldn't be doing the plants any favors leaving them in such small pots. And as you suggest, loosen the roots.
- I think you mentioned in your last post that you soaked (rehydrated) the pots, that was a great idea.
- Carex and Acorus foliage I would leave alone - they don't usually like to be trimmed in the fall & they get ratty over the winter anyhow. Maybe plant them behind a larger grass to give them protection from the direct sun.
- All others I would trim ALL the foliage to at least 3 inches or shorter. (I just saw a pennisetum at this plant sale that had been giving a buzz cut and it had lots of new growth)
- Fertilize with the same mixture you use for seedlings - ie high middle number to encourage root growth. You can do this right away, when you plant them.

With a little continued TLC your plants should survive just fine.
A.
btw, you could pot them in bigger pots as you suggest but IMHO most things do just a little better right in the ground (unless your ground sucks).

Thanks, A. I'm potting them up in 300's because there is no ready bedspace for them. I'll bury the pots in the Tomato Patch for the winter. It's tucked in behind a hedge of Miscanthus which will protect them from the north wind, but give them max sunlight.

Question. Why cut all the good foliage back now? I figured I'd leave the good blades, to provide some photosynthesis while they establish. They'll all get haircuts after winter anyway.

I don't use ferts, except for the mild stuff in MiracleGro Potting Mix, which I cut into my potting mixes in varying ratios, depending on the plants. These guys are getting 5:1 homemade mix:MiracleGro. I use seaweed tea and compost tea as liquid ferts, and just compost otherwise.

Now tell us what goodies you brought back from the sale!

I have found that cutting back foliage actually encourages new growth. Definitely the case with the Calamagrostis.
AND
I would cut the others back by at least half ~ they do gain in terms of photosynthesis but, if the roots are stressed &/or the leaves are yellowed by lack of light then the plant my loose more moisture than it can replace.

the grass end of the plant sale goodies included
Variegated Arundo donax (4), Miscanthus 'Sarabande'(5), Miscanthus 'Little Kitten'(6), Sporobolis heterolopsis(3), Panicum 'Warrior'(1), Pennisetum 'Karley Rose'(1) ~ all in 6" pots (1 gal)
and ... Carex nigra 'Variegata' & Bouteloua gracilis ~ in 4" pots.

Ok...I'll compromise. I'm cutting back all the foliage that isn't perfect. As regrowth starts filling in, I'll cut back the longer foliage. They'll be getting plenty of attention with regard to moisture, so that won't be a problem.

That sounds like quite a haul. I've been lusting after A.donax variegated, after seeing 'Peppermint Stick' in the Plant Delights catalog. It's probably too big for my garden, but hey, I started 4 S.ravennae this year. Who needs trees?

Donn,
lack of moisture not necessarily related to your ability to provide plenty of H20. I was thinking more of the condition of the roots and their ability to deliver H20 to the rest of the plant. That is usually the reason for reducing the size of the top of a transplanted plant.

base your decision on the condition of the roots.
A.

Just finished potting everything up. The roots all look fine, although they took a good bit of teasing. The Acorus especially were very pot bound in their little 50-pak cells.

It may be my imagination, but I think the plants I potted on Saturday already look better.