Q. I thought petunias were easy to grow, but I always have such a time with them! Their foliage is stunted, and they scarcely flower. They're getting plenty of sun. What could be the problem?
A. Petunias are pretty particular: they need full sun, good soil and regular watering and feeding. They also don't do well with too much water, so an extended rainy period will tend to make them stunted and/or prone to disease.
Here's a checklist:
1. Give them good, well-draining soil; amend the soil where you plant them. If you're growing petunias in containers, make sure to use fresh, high-quality potting soil. Using leftover potting soil from the year before could be introducing them to disease.
2. When putting in transplants, rough up the outer edges of the root ball — or split it apart — in order to encourage the roots to expand into the new larger container.
3. Pinch back the stems to encourage branching.
4. Feed once every two weeks with a balanced fertilizer.
5. If you live in the South, use Wave petunias or other varieties that have been bred to handle humidity and rain.
6. Petunias need full sun — five or six hours are okay, but 8 or 9 are even better.