They're different cultivars...and there are at least two more blue cultivars as well; 'Blue Heaven' AKA MinnBlueA and 'Aldous.' 'Prairie Blues' and 'Aldous' can be successfully grown from seed, while the other two are less cooperative. 'Blue Heaven' AKA MinnBlueA is the tallest and most erect in habit. All 4 are different shades of blue, ranging from blue/green ('Aldous') to steel blue/burgundy ('Blue Heaven').

donn, I think you must be spot on -- we do have heavy clay here and I probably wasn't aggressive enough about prepping the soil. I'm seeing the same phenomenon (to a lesser degree) with another grass (Sea Oats 'Rivermist') in another border too, so I'm guessing that the grasses' roots penetrate deeper into the soil? Since the other plants in the same borders, planted around the same times, are not doing the same 'heaving'...

Jim, The best time to divide and transplant (here in Ohio, at least) is in late March through mid April, before any new growth starts. But frankly, the plant can be divided and transplanted just about any time, even now in the middle of the growing season, if you are sure to slice off the leaves and take a good chunk of root and set the new division firmly in the soil. Keep it happy with moderate watering. It's just like a bison eating the top of the plant. It's adapted to being nipped off at the base. Those of us with experience with this species know that it grows slowly when young (first two or three years), or when transplanted. The species grows on root reserves, not just on leaf photosynthesis, so the plant can take a few years getting a massive root system in place to store energy. It's greatly helped with fertilization in the first three years. For small plantings, a general plant fertilizer like Miracle Grow is good. Don't over do it. Keep us posted on how things work out. --John Blakeman

Big Bluestem is not a scourge in my book. BUT in this conversation , many things are called Bluestem and they are not even of the same family as each other. Big bluestem is Androgon gerardi which is different from Little Bluestem (Schizachyrium scoparium). They are totally different from KR bluestem (Bothriochloa ischaemum var. songarica is in the same family as Silver bluestem )Botriochia laguroides ssp.torreyana and Botriochloa barbinodis. These grasses don't look a like and come from different continents. It is confusing because there are many many bluestem varieties within the various species. It gets mind boggling. I do a lot of walking around and looking in fields and gardens. TXranger is much better at grass IDing than me. God luck. Right now, I am trying to tell the difference in the field between Silver Bluestem and Cane Bluestem. They are both blooming and look similar in the pics online. I am trying to collect seed and want the cane bluestem. I do not want to be seeding non native purposely by accident . If you know what I mean. How do I tell them apart. I go to google and type in their names and pull up images. Ladybird Johnson wildflower center data base is a good place to go . So is Santa Rosa Garden Gardens has a bunch of bluestem.