Answer: Since you are looking into doing this commercially, I would suggest you work wiht the county extension in the area where you are headed. Here is a link to get you started; if you scroll down that page to the bottom left there are some additional resources you may find helpful.
They should be able to help you determine which plants would be best suited to the area and growing conditions as well as possibly work on a locally appropriate business/marketing plan for your greenhouse business.
Here is some information about planting natives in Montana.
The Montana Nursery and Landscape Association might be a good resource for you.
Another resource might be through your current wholesale contacts.
I hope some of this is helpful in your planning. Best of luck with your move!
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