Outsidepride Blue Mexican Petunia Dwarf Flower Seed - 30 Seeds Mexican Petunia Blue grows as a perennial in USDA Zones: 8 - 10. It prefers full sun and is both heat and drought tolerant. Ruellia Brittoniana is considered a dwarf Petunia only growing to a height of 10 - 12 inches with violet to blue blooms from late spring to late summer. This low-growing flower makes the perfect container plant, hanging basket flower, or ground cover. Sow these heirloom seeds at 1 - 2 seeds per plant in well-drained soil and keep moist until germination occurs in 7 - 10 days. Our seeds are always Non-GMO and packaged for the current year.