Have big opening with cinder blocks. 1 rose bush inside
Other than using cement between the blocks to hold them. You could try driving rebar through the holes to help hold them and keep from shifting. Stack them in straight line, On second row shift to side by one space(half block). Then drive a piece of rebar through each hole OR along the sides of stack. You can paint wall if you like and if you add dirt in holes you can plant some extra flowers in them.
Spray paint , then partially sink blocks and fill holes with hardy sedums or other ground cover plants
What a gorgeous hunk of land! You are so so lucky! I would leave as is and plant herbs, sedums, vinca, even sunflowers or whatever will grow well in full sun in your zone in the holes of the blocks. For the interior, I would buy some benderboard and either go eccentric or formal and section off with the benderboard. Fill each section with mulch, gravel, or rocks to form a patchwork type effect. When you want to add a plant, brush away the mulch or rocks, drop in your plant, add a ring or border around the plant and redistribute and fluff up the ground cover material. I would also add height with shepherd's hooks with bird feeders or yard art if you are not keen on feeding wildlife. Even some solar lanterns would look really cool. Install a little path and add a bench or a couple of chairs and a tiny table for beverages and snacks. It could look really cool, in a short time with a minimum of cash outlay.
I'm retired and like to make things easy. I would sell the concrete blocks and use the money to pay a landscape company to lay down a curb poured in place. They have a little machine that they pour a concrete mix into as they slide it along the predetermined path. This keeps the weeds down and provides a nice looking border that is easy to trim along with the lawn mower. Loose blocks and stones are a real pain as you have to move them to trim out the weeds all the time and never looks finished.
Looks as though you have enough pavers to create a nice focal point for your backyard. But you really need to create a garden plan first ! Look at your yard and envision the FLOW you wish to create, what you want to accentuate.
The most natural look is to curve the blocks. Then plan to raise the bed by adding a lot of quality garden soil, then plant. like in this pic. You plan your garden by putting the shorter plants in front and increasing height toward the back, or center.
Plan it out!! Enjoy looking at other ideas.
You should also consider where the focal point should be a work around it. Here are some pics to help you get started.
Thanks I will do this