I haven't. I have always just assumed we were too warm. I'd love to know if they will grow here.

Have you grown nigella? I have, it grows well here. Annual, and brief, but fun!

Here is a link that might be useful: Nigella

I'm not in NE OK, I'm in SC OK. I sowed the seed of the Himalayan blue poppies one fall and they never even sprouted. I was so disappointed because many other kinds of poppies have done well here. Clearly all the other poppies I grow originated in areas with a climate more like ours. The blue poppies were an impulse purchase from a seed rack and I had no idea what conditions they needed, but figured I could spend $3.00 to give them a try. After they failed, then I did my research and learned they didn't have a chance of growing here in our climate.

They are native to the Himalayan Mountains where they grow at high altitudes that never get very hot at all. They are extremely challenging to grow anywhere in the USA, but some people have been able to grow them in Alaska and in some selected areas of the Pacific Northwest. If you were able to get them to germinate and grow, they would have to finish their bloom cycle before temperatures ever hit the mid-60s. Something about the heat also ruins their blue color. And, they have to have a long winter with temperatures around 32 degrees in order to make it through the winter and have a chance to bloom. Other than that, growing them should be a piece of cake. A very rare cake we'll never see in Oklahoma. I think blue is one of the hardest shades to get in flowers here, especially with warm-season plants.

For blues, I use larkspur, salvia farinacea and some other blue-flowering perennial salvias, bachelor buttons, scabiosa, Heavenly Blue morning glories, veronica, agastache, and bog sage. Of all those, bog sage, which is Salvia uliginosa, might come closest to having that bright sky blue of the Himalayan poppy. Salvia guarantica has some pretty light blue shades too. Bog sage really likes moisture so probably would be happier in NE OK than in SC OK. It is only happy here in wet years, which are increasingly few and far between. There are other blue-flowering plants but a lot of them prefer cooler weather than we have. I love lobelia and want to buy some every year when they pop up in the bedding plant sections of the stores, but it seems pointless. If they even survive until June here, the heat just slays them. There's a few blues you can grow from bulbs---I've had some Dutch iris and hyacinths that veered more towards blue than purple. I had luck for a couple of years with bluebeard (aka blue mist spirea) but it really needed soil that drained better than our clay does and I lost it in a flooding rainfall type of year...probably in 2004.

My main blue flower that I grow here is Texas bluebonnets. The aren't crazy about the clay, but there's a couple of selected spots where they tolerate it right on the edge of the gravel driveway and reseed readily. They only bloom for about a month but I enjoy the blue flowers while they last.

Black and blue salvia will give you a dark blue. If you ever plan to come to the plant swap give me a holler...I will dig some up for you.

I thought of another blue flowering plant that grows well here----The hardy hibiscus "Blue Satin". That's a variety that's been around a while. There might be a lnewer blue hibiscus with a different name. Last year I planted Agastache "Blue Fortune" and those plants did really well in the back garden's sandy soil.

One of the most reliable blue bloomers we have in our yard is blue star grass. Don't forget that borage blooms in blue too. Bees love borage.

Once you start thinking about the there'll quite a few different blue flowers that do well here in OK but a lot of them are shades that lean towards being purple.