Petunias are one of the most popular flowering annuals. There are many varieties of petunias, all of which fall into one of four categories, according to the University of Minnesota Extension Agriculture department.
Categories are grandiflora, with large flowers 3 to 4 inches across; multiflora, smaller, but with more individual blooms; milliflora, smaller and more plentiful still; and groundflora, or spreading petunia, which can cover a large area over a growing season.
Petunias can be a bit finicky in cold weather, so it's advisable to wait until all frost warnings for the season have ended before planting them.
Diane Young, an employee at The Barn Nursery, offered some tips for planting and caring for petunias.