I have 2 that came up volunteer that are about the size yours are this year and have that same upright appearance (upright now anyway). I'd mistaken the identity thinking they were Indian Rice Grass where I'd sown seeds. I'd leave them where they are because they have nice late afternoon sun nicely showing off the pink but....they get so large they will be too big for the spots so I am moving them next spring while they are still a moveable size (gallon sized). Too bad because currently they look great and I wish they'd stay that size. A mature plant gets 3 feet, forming a very thick, dense tussock that forms a perfect half circle shape (no longer the upright look) that is just as tall & really takes up a big space, its more like a specimen grass which I hadn't expected. They are a bear to trim down in spring. I took one out this spring to open up some space and in its spot there are now 6 bluestem plants with room to spare. I had no idea they got that big.

Peren.all, you would probably be able to grow Muhlenbergia riverchonii, its often sold under the name 'Undaunted'. Its a lot more cold hardy and personally I like it better. Even if you could grow the Gulf Muhly you might never get the blooms because the Gulf M. blooms so late in the season, my big guy is just now starting to put up a only few blooms even though the two volunteers bloomed earlier and are in full bloom. The M. riverchonni starts to open in July and is in full glory by mid August, then it looses the color but stays nice and hazy looking until its cut back in late winter. It is more subtle in color---kind of a dusky pinkish purple color + its a smaller, lower growing grass with leaves that are just as fine but more grayish green. I think the Gulf M. looks more 'tropical' because its so garishly pink with brighter green leaves.

These use to be 2 plants.I divided them 2 yrs ago .I have a small fifth one that sprung up on its own behind these.I am a dividing machine lol..I have tripled my plant collection in 3 yrs .Dayliilies, grasses, spirea, monkey grass, iris is all, the plants I have been dividing with HUGE success.

When the sun sets these almost glow purple.Its a beautifull grass.

Randy Man, don't get me wrong, I think its a beautiful grass and hate that I have to move those two. I'm not into dividing it to keep it small because that screws up my gravel mulch too much.

People in more northern parts of the country cannot grow it so I always make a point to mention the other Muhly grass as an excellent option for further north. Gulf Muhly is commonly sold and very well known in the trades but M. Riverchonni (Undaunted) is much less known, less commonly sold and therefore less commonly grown but the best thing is its one they can grow up there + it blooms much earlier giving a several weeks longer of ornamental effect which is a factor as well. I wanted to point it out because it would be similar to Gulf Muhly but definitely not a grass you'd be settling for as a poor substitute because it is just as ornamental and in truth since I grow both types, I like it better for size, color, longer bloom time and over all appearance.

Thank you TR I will certainly be keeping on the lookout for M. r. I can picture it in my garden in combination with so many plants including other Ornamental grasses. We have already had frost so its earlier bloom time is a real bonus.

peren.all, It appears that Muhlenbergia riverchonii is listed in the catalog of Lost Horizon of Acton Ontario.

Lost Horizon

Santa Rosa Gardens has it. Its listed as "Undaunted" but its definitely Muhlenbergia riverchoni, it will be available in spring. Cold hardy to zone 5. One thing I like is that you get a long season of pink/purple if you grow both kinds. The M. riverchoni is past its prime and is now a haze of beige but the Gulf Muhly is in full swing. That gives you 3 months of 'ethereal haze' in two shades. I think it would be interesting to plant these as layers in two groups of mass plantings, the effect would be nice. I'd put the undaunted in front since its not quite as tall.

It hardly ever puts out seedling volunteers. Every time I find one, and thats been rare, I consider myself lucky.

Muhlenbergia rigid "Nashville" is also known as Purple Muhley Is hardy to Z6 (-10). it ia a west Texas , New Mexico plant. God knows why the trade variety name is Nashville

Muhlenbergia rigida "Nashville"

I can testify to the hardiness of Muhlenbergia reverchonii. It's been through temps of 16 below, with snow cover, and temps near zero without. It's slow to increase in size, but so lovely in bloom. The pink is fading to tan now, but it's still lovely.

I get seedlings of it here but they are very slow to grow.

UPDATE!!

My 4 needed a good cutting as they where almost laying down from this past winter, so I decided to do a divide on all 4 of them in early march .BTW I made 4 plants into 14 :) One of the 14 only has about 4-5 green shoots coming out.But all the other 13 are doing great..They just look bad from the pruning down I gave them.I doubt I will ever cut these back again.I dont think they liked it.Maybe because we have cold winters here. Heres a picture I took this evening