By no success do you mean the plants died or that seeds did not germinate. Do you want Tennessee native plants or do you just want a colourful meadow?

The easiest way is to buy plants, growing from seed is more complicated. Prepare the bed as you would for perennials: remove weeds and grass (search this forum for lasagna method or newspaper method), dig in some compost, cover with 2"-3" of mulch. Then select plants that suit your sun and soil and plant. This is not a good time of year to plant, better to plant when cooler in spring or fall but you can prepare the bed now.

Tell us about your soil, soil moisture and how much sun the area gets, what size the bed will be and how tall you want the flowers to get and we may be able to give you more assistance.