How to Get Petunias to Last Throughout Summer

How to Get Petunias to Last Throughout Summer

There are over 100 petunia varieties. The trick in the home garden is to get them to last throughout the summer. Petunias are annual flowers available in many different varieties, colors and growing habits. Follow these tips to grow brightly colored petunias that will bloom throughout the entire season.

Petunia Varieties

The so-called old types of petunias are multiflora and grandiflora. Multiflora petunias--as the name implies--flower more freely and tend to tolerate more adverse heat and weather conditions than grandiflora. In size, multiflora varieties have blooms from 1.5 to 3 inches in diameter, compared to 3 to 4-inch diameter grandiflora petunias.

Newer varieties of petunias are those classified as spreading-type plants. Low-growing spreaders reach heights of 6 to 12 inches and can be used as ground cover or in hanging baskets in full sun. Many of the Wave petunias—which have flowers in colors of pink, rose, misty lilac, lavender, blue, and purple—grow 24 to 30 inches wide and 8 to 10 inches tall.

Consider the many varieties of petunias, available as singles, doubles, petunias with contrasting edges (called picotees), striped ones, veined, trailing, dwarf, tiny blooms, medium-size blooms, and large blooms.

Stagger plantings of petunias. Some are early bloomers, while others are so-called perennial bloomers (the Colourwave variety) that last 6 to 9 months.

Sun and Soil

To proliferate, petunias aren’t too picky, but they do need full sun. Petunias need at least five hours of sun a day to do their best.

They also like a well-drained, slightly acidic soil. Keep mulch away from stems of petunias. Add peat moss to your soil if it does not drain well.

TIP: Our expert gardening advisor, Susan patterson adds, "Spread a thick layer of organic matter on top of the soil and work it in before planting. Fertilize every three weeks with an 8-8-8, or 10-10-10 fertilizer."


Water petunias before noon early in the day. While spreading petunias require extra water, other varieties do well with water once a week. Hanging baskets and container plants require more water.


Cut back to the newest set of leaves on each stem. Do this in the cool evening. Pinch off blooms after they’re spent, a practice known as deadheading. This encourages the plant to bloom again. Pinch out the very first flowers before they begin to bloom. This makes seedlings branch out. Plants will then produce more flowers and larger blooms with deeper color. When petunias are done flowering, prune them back. They will grow and bloom again in the same season.

Hanging Baskets

For hanging baskets, make sure pots have adequate drainage. Place small stones or pebbles in the bottom of the pots to avoid soil leaking out. Move hanging baskets to an area where they only receive morning sun, as afternoon sun causes them to dry out and droop.