Blooming purple and white petunias grow in the garden. - Just dance/Shutterstock Why buy new petunias (Petunia x hybrida) every spring when you can turn one plant into many? The secret is cuttings.

These pretty, purple perennials are resilient and cold-hardy. Mexican petunias are fast-growing plants native to warm parts of South America and Mexico, but they can tolerate cool temperatures in ...