I have to tie it up or let it lean on a trellis. It is only 2 years old maybe 3 at most and I cut it done just before first frost. I cannot send photo.
This often happens due to there being too much nitrogen in the soil. It sounds like you are doing what needs to be done until the plant gains its ground and once it takes most of the nitrogen out of the soil. This article will help to lower nitrogen:
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/too-much-nitrogen-soil.htm
This will give you more information on the issue at hand:
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/too-much-nitrogen-soil.htm
This will give you care tips:
https://www.gardeningknowhow.com/ornamental/foliage/little-bluestem-grass/little-bluestem-care.htm