Here’s the two-tier flower beds. I had lots of mismatched flowers and perennials and now restarting from scratch. I am looking for a simple design, no flowers/colour. I like what I get when I google modern farmhouse flower beds (please don’t be mad, and I know I don’t have a modern farmhouse house…). I don’t know what to put where. How high (not above window silk?)?

I was recommended and bought 3 Karl Foester reed grass but not sure where to go from here… Photos below… please help.