Those planted in the fall in South Louisiana will last through the winter - as long as mild climate conditions prevail, they say. For success with petunias in the landscape, the horticulturists say to select a fertile, well-drained soil. A raised bed is preferred, according to Trawick, who says to add organic matter to improve the physical properties of the soil. An ideal soil pH for petunias is 5.5-6.0, since they prefer acid soil conditions.
Numerous petunias are available.
Classes of petunias are usually grandiflora or multiflora. A newer group of petunias characterized by smaller flowers on compact-growing plants is the Fantasy series. These ground-cover plants need 2 feet between plants. For additional information on care of your landscape plants, contact a county agent at your parish LSU AgCenter Extension office.