Acclimated plants are very tolerant of cooler to cold temperatures. In zone #5 they do best in the early spring to early summer (May-June), have a tendency to slow down in the hot drier months and than come on strong in the cool fall (mid-September-October). With a little protection I have had Petunia's in bloom on Turkey Day. Hardened Petunias can be plant in early May (zone #5)
Flowers
tubular, 8 different colors
Leaves
alternate and covered with a viscid pubescence, making them sticky when pinched