Trim the tops off the beets and put them in a single layer in a casserole dish. Cover with foil and bake until the beets are just tender, but not soft. Check with the tip of a sharp knife. I like them to be tender but still firm. The exact time will vary greatly depending on the size of your beets. Check small beets after 30 minutes, large beets after an hour. Let cool and then remove the skins. Chop the beets into bite sized chunks or wedges.
Meanwhile cook the wild rice according to the package directions.
Add the beets, onions, celery, blackberries, and herbs to the bowl and toss with the dressing. You can either add the red beets in now, or reserve them to tuck in just before serving, your choice. They will bleed their color into the salad the longer they sit.
Garnish with crumbled feta cheese just before serving.