Not sure of the forum on which it was mentioned but someone liked the circular pattern of different colored blocks I used for some of my raised beds. The blocks are 4Hx8Wx12L and came in gray, brown, and red. Purchased from Lowe's and they may now have an additional color or two. Requires 12 for the bottom layer and, since they are alternated over the joints and have an inside locking 'lip', 11 on the top layer plus half of a brick to fill a leftover gap.
Single layer for a tree/patio rose mulched with white marble chips for contrast.
Double layer for a newly transplanted peony.
This makes a circle of about 34 inches which is adequate for one peony or rose. It would also be perfect for one 'drop dead gorgeous' iris to be displayed and not disturbed for a few years. The cautions to be considered are a raised bed with cracks will dry out quickly in the heat of summer and, also, humus and organic material tend to rot and shrink more quickly than one would think so the filler material should be compacted to approximate natural soil and mounded slightly to compensate for shrinkage.
