Find a nice, sun-drenched part of your landscape for this beauty, and prepare your planting area with a bit of controlled-released fertilizer that is mixed well with soil to prevent root-burn. Petunias are hungry plants, so although this one feeding can sustain your plant for a growing season, if you are using this plant as an show-stopping annual, you might decide to fertilize again in a couple of months. Covered in flowers, this plant should look great all season, but if by chance it begins to look tired, perk it up by trimming it by 1/3 of its size.