Q: Last summer I hung two pots of petunias on a south-facing raised deck. By August they looked terrible. This spot gets a lot of sun and wind. What would be a good flowering annual for this location?
—T.V., Proctor, Minn.
A: Like other sun-loving annuals, petunias should do fine, but wind can quickly dry them out. Unless you can devise a windbreak, you might do better with portulaca or sedum, but they wouldn't provide the same kind of effect.
If you can't block the wind but still want to try petunias, make sure the container is extra large, use a top-quality potting mix, and water as needed to keep the soil evenly moist but not sopping wet. You may even need to water twice a day — or you could experiment with a self-watering pot. Feed the plants regularly with a water-soluble fertilizer for blooming annuals; read and follow label instructions (too much fertilizer isn't better than not enough).
Finally, many varieties of petunia need to be cut back by about half when they get leggy. Cutting back will force a flush of new vigorous growth and lots more blooms, even into the fall. Also, regularly remove faded flowers to encourage more bloom and to prevent the plant from using any energy on producing seeds. Or you might try one of the newer varieties that are developed to be self-cleaning and naturally large and full.
— National Gardening Association
