The Best Petunia. Period. Supertunia Vista petunias are very vigorous, with mounding habits that can reach up to 2 feet in height in the landscape and will trail over the edges of baskets and containers up to 4 feet by the end of the season. They are fantastic landscape plants and are great in large containers, where they function as both fillers and spillers. In garden beds, they will work either in the front or middle of the bed. They have medium-sized flowers.