What to Do When Wave Petunias Not Blooming

To a flower gardener, few things are more satisfying than a hanging basket overflowing with masses of blooms. Although wave petunias lack the stop-in-your-tracks scent of the traditional variety, they provide an eye-catching cascade of bright white, pink and purple flowers that last as long as the warm weather holds. If your once-beautiful wave petunias stop flowering before their season is over, a few approaches will likely remedy the situation.

A Sense of Place

Petunias in general are fairly hardy plants during warm weather months and do well in most types of soil. Although they are somewhat drought-tolerant, they prefer a moist, well drained, loamy soil. When watering wave petunias planted as ground cover, direct the water toward their roots. Waterlogged blooms will turn to mush and fall off. Aphid attacks, though possible, are rare and tend not to affect the plant's ability to flower. Wash these tiny pests off with a light spray of water, and then gently shake the water off the blooms to avoid soft rot.

Regardless of soil conditions, a petunia plant will bloom either sparingly or not at all if it doesn't receive enough light. These sun-loving annuals bloom most abundantly in full sun and stand up to heat particularly well. If you have a hanging basket of wave petunias that aren't blooming or have stopped blooming, check whether it's in partial or full shade. Switching the plant to a south-facing porch or wall hook will provide the full sun exposure it needs, ensuring a magnificent display all season long. If you're using your multiflora as a ground cover, transplant it to an open space where taller plants won't rob it of sunlight.

Care and Feeding

Wave petunias are an increasingly popular class of the multiflora petunia hybrid. Their 1- to 1 1/2-inch flowers grow quickly and tend to out-bloom and outlast their larger, delicately scented counterparts. A well-fed petunia, regardless of variety, will reward you with healthy foliage and masses of color. To revive the blooms on your plant, once a month, add a phosphorus- and potassium-rich fertilizer to your watering can and give the petunias a good soak. The rest of the time, keep the soil moist. Hanging baskets in full sun often need watering once a day to thrive during the hottest days of the summer. You may get lucky and be able to completely revive a drooping petunia, but there's a fine line between droopy and dead, so watering often is highly recommended.

Drastic Measures, Dramatic Results

All varieties of petunia benefit from constant grooming. If the foliage is growing without blooms, pinch off the old withered blooms. This make the plant substantially more attractive and redirect the plant's energy into producing more flowers. Though you may be tempted to let the plant continue to grow in length (up to 3 feet for the wave variety), you'll discover it becomes less attractive and more scraggly when it's allowed to continue down this path. Mid-season, bite the bullet and cut back the petunia plant by half. Within a week you'll be rewarded with a resurrection of the bushy, flower-heavy plant that tempted your pocketbook at the beginning of the season. All season long, don't hesitate to cut back any rangy growth for the same result.