I'm in zone 8 and I have it in several places, not all by choice--make sure you really want it before you plant it and then be diligent about deadheading and shovel pruning to keep it in bounds. Perhaps it's not this way in everyone's gardens, but it certainly is in my heavy clay and I'm having a very difficult time eradicating it. I do like the flower, and if it's cut back it has a very long bloom season, and yes, I do see bees on it.

Thanks, harleylady

The area I have in mind is bounded on two sides by deciduous Magnolias, underplanted with evergreen Azaleas, so I don't expect there to be a problem in that direction. The native Aster, Symphyotrichum georgianum, is a notorious spreader, but has never penetrated that barrier. One side is a street and the fourth is a neighbors Zoysia grass lawn, which I constantly battle, to keep it from overtaking my flowering plants. I wouldn't mind another plant that could help with that annual chore!

I need to visit the Outlet center this weekend to pick up several Belladonna Lilies that have just arrived and will probably pick up a few one gallon sized Mountain Bluets. If the weather will cooperate for a few days, I may even have a chance to plant them! Five inches of rain this week, 30 inches during past 60 days, which is normally our dry season.
TA

Mine moved across the dark dry shade underneath a huge old walnut tree and now is growing up through an agapanthus, a hardy fuchsia, my Japanese blood grass, and several other choice perennials...just saying...YMMV

harleylady___
Thanks for the heads-up on the Mountain Bluets. I was considering planting some in my garden, but if there is one thing more I need, it surely isn't another invasive plant.
It may be well behaved in the heat and humidity prevalent in this area, but I am not taking any chances!

They spread by seed. The parent plant will enlarge but it is moderate in doing so. A mature plant in my zone 5 is a foot across. I have grown it for years. I still like the plant even though it is a liberal seeder. It is nowhere near as bad as lambs ears, which I had to eliminate entirely and am still finding babies 3 years later.

I dead head pretty carefully now, but some still escape. Goldfinches love it. I used to leave the heads on for them, but had too many sprouts.

In the fall after everything dies down I go out and dig up the babies that may have sprouted, especially inside other plants, and transfer them to a holding bed to await trades. I do the same in spring for any escapees. They are not deep rooted and easy to dig up with just the point of a trowel or a knife. I always find lots of people want it at a swap I go to. I warn everybody about the seeding.

It can look weedy after first bloom. You will get repeat bloom if you cut the while plant down to about 4-6 inches, when it will make a new neat crown of leaves

Thank you, linnea, for the commentary; I thought I was doing something wrong since it didn't seem to be very happy. Not dead, but just not getting bigger.
Another thing to add to the Bluestone order this spring, I suppose, since I really love this, but I don't get so much as a new seedling...ever. And I have nice soil, too! It'll give me an excuse to try the Amethyst and the white one, too!

Crap...I just went to Bluestone, and it says I need to put it in "poor, alkaline soil."

Just curious...how does one GET "poor, alkaline soil?"

I think one doesn't get it, one is cursed with it.

I've had Centauria montana in the garden for about 10 years, I get the odd seedling but it hasn't been a problem for me. I've only had to pull one or two out where they were not wanted. I usually cut mine back after the first flush of blooms, they usually bloom again later in the season.

Went to the Outlet on Sunday, but they had sold out of the Mountain Bluets.
Probably just as well, since I don't have any "poor, alkaline soil" to plant them in! All of my garden is red clay based, heavily amended with compost during 43 years of gardening.

[mmqchdygg, Just curious...how does one GET "poor, alkaline soil?"]

You can add ground limestone and sand to planting hole to make soil more alkaline.

I often have same question about making soil "lean" for some plants.

Think centaurea montana is relatively tolerant and might do well with addition of hydrated lime in planting hole. Just mix in well, cover with some less rich soil (bagged garden soil?) or coarse sand so roots don't get burned. Important to follow bag application rates carefully.

Also make sure surrounding plants aren't sensitive to soil ph rise with lime.

Once you see those photos with diadem shaped flowers it's hard to resist trying!

Here is a link that might be useful: What ph Means In Garden Soil

In my garden it is not picky. Most are in a raised bed with amended, moisture retentive soil, that gets top dressed with compost every spring. I have moved it as well to unamended clay soil and the performance looks exactly the same. I do have more seeding in the moist soil.

They do also spread by underground runners and if you don't get it all out, they will keep coming back which is why I have such a problem with it. In my heavy clay it's difficult to get all the bits of stolon out. I wouldn't worry too much about the poor alkaline soil as they seem to do well here no matter where they're growing, although that may have more to do with our milder climate than the soil.

ladywindsurfer, wanted to email you but you don't have an active email link..please email me at my hotmail account HarleyLady_01 about the C. montana

Iagree & find if you cut them back severly after they bloom each time the clump looks healthier and doesn't spread as much.
The Amethyst flowers are quite nice also. I think as long as you are diligent at deadheading you'll be alright.
Sometimes I envy you growing season etc. and other times I'm happy for the downtime Lois