Began a new thread rather than clutter an existing one. This is my favorite raised bed for one peony. The blocks are 4x8x12, if I recall correctly, so it gives a depth of 8 inches which is the minimum for a raised bed. The blocks have a lip on the bottom inside edge so it requires 12 blocks on the bottom row with 11+a small filler on the top row. I alternated the colors for visual effect. Plan upon the soil settling over time so firm it before planting the roots and mound the soil as high as practicable.
This is from 2013 and the bed has been removed for grass planting last fall. The peony is from Lowe's or Walmart so has no true name. I seem to recall it is one of the Crouse cultivars.
Changing the count of the blocks to 12 on the bottom and 11 on the top. Memory is not as good as it once was.