There might be better funded efforts assisted by famous designers doing good. But the small heartfelt efforts with little more to work with than a left-over side lot of weeds, volunteers and some scrappy Michiganders are what it is all about. Like a recent effort where a new memorial garden was dedicated for veterans - here and gone.
These folks showed up with heart and used what they had to make space sacred. Every time they pass those signs, or flowers or weeds they will remember that they stood up and said to the world that their loved ones mattered and what they went through did too.
There is no greater gift than to remember love: their love and ours. It helps us who remain, inform the time we have left to live.
In parallel, however...my landscape architect "hat", would recommend planting something enduring. A simple grove of evergreen trees might ground and tether their memories to this place to hold the sacredness past their own dedication and presence there.
“The best time to plant a tree is twenty years ago. The second best time is now.”- Anonymous.
But they did good, even without a pro to help.