GROWINGPetunias are quite heat tolerant, so you shouldn’t have to worry about watering them often. A thorough watering once a week should be sufficient (unless there are long periods of drought in your area). Avoid shallow watering, as this encourages shallow roots.Note: The spreading types of petunias and those in containers require more frequent watering than those planted in the ground.Fertilize petunias monthly with a balanced fertilizer to support their rapid growth and vigorous flowering. Double-flowered varieties enjoy a dose of fertilizer every two weeks.What to do with leggy petuniasBy midsummer, most petunias tend to become leggy, producing flowers at the tips of long, leafless stems.

To keep petunias looking nice and blooming, we prune the shoots back to about half their length. This will encourage more branching and more flowers.After pruning, fertilize and water the plants well to force out new growth and flowers. The plants may look ragged at first but they will come back with more color and flowers.Older garden petunia plants can be pruned back hard (within a few inches of the base) to reinvigorate vigor, especially in colder climates, but keep the remaining leaves.Remove faded, old, or dead flowers (a practice called “deadheading”) to improve both blooms and attractiveness, especially for petunias with larger flowers. Deadheading prevents seed pods from competing with flowers for the plant’s food supply. Clippings can be added to a compost pile to be recycled.