Ask-a-Dave's-Gardener: Help with Northwind Switchgrass not thriving, 1 by owltraveler

owltraveler wrote:
The last two years my Northwind switchgrass has declined.

They used to be thick, creating a nice natural barrier on one end of the front porch.

Now they are thin. I divided the larger plants a few years ago. The only thing I can think of is that they are in a raised bed (about 3 feet high) and maybe the soil needs some type of amendment.

They are one of my favorite features in the garden. I\'d love any suggestions for how to bring them back to life.

Thanks!