Petunias are one of the most popular flowers, often grown as annuals. They are tender perennials in Zones 9 to 11.
They are divided into two different groups:
1. Grandiflora petunias have very large flowers and are best grown in containers or hanging baskets (because they are more susceptible to rain damage).
2. Multiflora petunias have smaller, but more abundant flowers and are ideal for summer bedding or in a mixed border (because they are more tolerant to wet weather).