Petunias: Rediscover These Amazing AnnualsA guide to growing gorgeous petunia flowers in your garden or in containers
Supertunia Vista® Bubblegum® grows at the front of this landscape bed. Photo courtesy: Proven Winners.
When I was growing up in the 1960s, my grandmother introduced me to purple grandiflora petunias, which she brought home from the nursery by the dozens to brighten up her summer garden. They were the first flowers I ever planted, and I have been madly in love with petunias ever since.
Today, there are even more reasons to fall in love with them because there are so many more choices. From compact types with dime-size blooms to trailing varieties that spread up to 4 feet, they now come in a wide variety of colors, sizes, petal profiles, and growth habits. This new-generation has also been bred to outperform their predecessors, producing nonstop blooms all summer long on sturdier, easy-to-grow plants.
Are petunias perennials or annuals?
Although they are actually classified as tender perennials, they won't tolerate frost so they are commonly grown as annuals in most climates.
Sun or shade?
Color and characteristics:
You can find them in just about any color, even black, as well as striped, veined, and speckled patterns. The variety of flower forms is also impressive, ranging from petite to palm-sized in single or double blooms with ruffled, fringed, or smooth edges.
Nearly all petunia plants sold today are hybrids. Some new petunia varieties and hybrids have become so popular, they have created a class of their own, such as the Supertunia® and Wave® series of plants.
Supertunias®:From Proven Winners®, vigorous bloomers that produce flowers in a broad range of colors.
- Supertunia® Vista: Landscape plants with medium-sized flowers, growing up to 2 feet tall and 3 to 5 feet wide.
- Supertunia® Charm: Densely-branched container plants with small flowers.
- Supertunia® Trailing: Strongly trailing plants with medium flowers.
- Supertunia® Double: Plants bloom with fully doubled flowers.
Spreading, or Wave® petunias: Introduced by Ball Seed Co., energetic growers with trailing stems that spread up to 4 feet or more.
Grandifloras: One of the oldest types, producing large, although fewer, flowers; mounding to 15 inches.
Multifloras: Blooms with smaller flowers and has a more compact growth habit.
Floribundas: Hybrids of grandiflora and multiflora, producing grandiflora-like blooms with the vigor of a multiflora.
Millifloras: Only about 8 inches tall and wide and produce tiny 1-inch blooms.
See more about the different types of petunias.
HOW TO PLANT PETUNIAS
When to plant:
In spring, after the threat of frost has passed.
Where to plant:
For the best performance, plant in full sun (at least six hours a day). They will tolerate some shade, but may not flower as prolifically.
They grow best in a light, fertile soil that provides good drainage and is slightly acidic (pH 6 to 6.5). In heavy clay soils, work some compost, or other organic matter into the ground before planting. When planting in containers, use a free-draining soilless potting mix fortified with a slow-release fertilizer.
Grow petunias from seed:
You can also grow many types from seed if you’re after a certain variety not available as a transplant. Because petunia seeds are very tiny and slow to germinate, you’ll have better success starting the seeds indoors 8 to 10 weeks before the last frost date in your area and transplanting the seedlings into the garden once the soil warms up.
Like many sun-loving flowering annuals, petunias need regular watering because their shallow root systems dry out quickly. However, make sure the soil is well drained because soggy soil can cause root rot and yellowed foliage. Petunias grown in containers may need more frequent watering, possibly every day, especially in hot weather.
Petunias need a lot of refueling throughout the summer to keep them blooming vigorously. Apply a monthly dose of liquid fertilizer or a slow-release granular fertilizer at the time of planting. Plants grown in containers often need more frequent fertilizing because the increased watering washes nutrients out of the soil.
Pruning and deadheading:
The amount of pruning required often depends on the variety you’re growing.
- Traditional grandifloras require the most work and need frequent deadheading to prevent plants from going to seed.
- Newer self-cleaning and spreading varieties will do fine without pinching or pruning, but occasional deadheading will boost flower production and create fuller plants.
- If your plants begin to get leggy and bloom less heavily, shearing them back will encourage new growth and more branching.
Pests and diseases:
Petunias can be bothered by pests like thrips, mites, caterpillars and budworms; as well as powdery mildew and various types of rot.
- Mites and thrips can be treated with applications of neem oil or insecticidal soap.
- Caterpillars or budworms can be hand picked and dropped in a bucket of soapy water, or treated with a Bacillus thuringiensis (Bt) spray, but don't apply when butterfly caterpillars may be present. Watch this video to learn more about how to get rid of budworms.
- Root, stem, or crown rot can be caused by poor drainage or overwatering.
- Powdery mildew can be caused by overcrowding as well as wet conditions.
Get more advice on keeping your petunias blooming all summer long:Caring for Supertunias® (from Proven Winners)
With more than 400 cultivars to choose from, and new selections being introduced every year, petunias are far from passé. Here’s a look at some of the dazzling new options you may have been missing out on.
Supertunia® Royal Velvet® — Buy now from Proven Winners
It's easy to see why this is a top seller! Royal Velvet® is heat and drought tolerant and produces an abundnace of deep purple flowers that attract hummingbirds and butterflies. Pair with just about any other color in beds, hanging baskets, and containers.
6 to 12 inches
18 to 24 inches
Supertunia® Black Cherry® — Buy now from Proven Winners
This stunning semi-trailing petunia is covered by cherry-red flowers with black accents from spring until frost. The plants can spread up to 2 feet in the garden and up to 30 inches when allowed to spill over the edges of hanging baskets and containers. Combine with two other Supertunias®, Bordeaux™ and Vista® Fuchsia.
6 to 12 inches
24 to 30 inches
Supertunia® Daybreak Charm — Buy now from Proven Winners
Ideal for containers, the Charm series features small to medium-sized flowers on densely branched plants that stay nice and full in the center without pruning. We’re particularly fond of this cheerful selection, featuring sunny yellow centers set off by watermelon-pink edges.
8 to 12 inches
18 to 24 inches
Supertunia® Bordeaux™ — Buy now from Proven Winners
The dramatic veining pattern of this purple petunia is unlike any other. This award-winning annual is prized for its vigor and ease—no deadheading required. Grow on its own or pair it with other strong growers like Superbells® Calibrachoa or Superbena® Verbena.
6 to 12 inches
18 to 24 inches
Supertunia Vista® Bubblegum® — Buy now from Proven Winners
Rock stars in the landscape, the Vista® series makes a huge visual impact. Bubblegum® forms a thick carpet of pink blooms that will quickly cover any empty, sunny space in the garden. Its stems will easily grow three feet long in a spreading mound.
12 to 24 inches
24 to 36 inches
Supertunia® Sharon — Buy now from Proven Winners
A double petunia hybrid, Sharon is heat tolerant and long blooming. Show off the bi-color pink blooms in window boxes, hanging baskets, planters, or at the front of a mixed bed or border.
6 to 12 inches
18 to 24 inches
Pirouette Purple Double Petunia
Here’s one that has come a long way from the old-fashioned purple grandiflora my grandmother grew. This eye-catching double variety shows off frilly carnation-like flowers with velvety purple centers and pure white edges. The plant’s mounded shape is an improvement over the sprawling habit of older grandifloras.
10 to 15 inches
10 to 12 inches
Petunia Night Sky®
White speckles on a deep-purple backdrop give this mesmerizing petunia the look of stars twinkling in the night sky. The variance between day and night temperatures is responsible for the astral display, causing the luminous white stars to appear in constantly changing configurations.
10 to 13 inches
20 to 30 inches
Tidal Wave® Silver Petunia
This award winner sports dazzling silvery white blooms with dark purple centers and delicate purple veining. Even more impressive is the plant’s ability to be used as a hedge, climbing vine, or fast-growing groundcover. Spaced about a foot apart in garden beds and it will grow into tidy hedge-like mounds under 2 feet tall. Plant more closely and give support, such as a trellis or fence, and it will climb upward 3 feet or more. Space up to 2 feet apart and it will become a groundcover, spreading up to 5 feet.
16 to 22 inches
30 to 60 inches
Cascadias™ Autumn Mystery
A semi-trailing petunia that keeps you in suspense with its ever-changing combination of colors. The blooms open with pale yellow petals and rich mahogany-brown centers, but the yellow gradually fades to cream and the mahogany to a deep purple shade as the flowers mature. This petunia also boasts a long bloom season, starting in late spring and continuing into early fall.
12 to 14 inches
16 to 20 inches
Wave® Carmine Velour
This latest addition to the Wave® series is lauded for its velvety carmine-rose blooms that remain vibrant, come rain or shine. Large, 2- to 3-inch flowers cover the entire plant, creating a beautiful blanket of color that lasts from spring until the first frost.
6 to 8 inches
3 to 4 feet
IDEAS FOR USING PETUNIAS IN THE LANDSCAPE
Petunias are very popular flowers for adding instant color to a garden. They are incredibly versatile and can be used in many ways. Here are some ideas:
- Plant them as colorful additions to seasonal landscape beds
- Grow them individually in hanging baskets or along with other strong growers
- Use them in containers as the filler or spiller component
- Plant petunias in masses for a dramatic blanket of color
- Cover bare spots in your garden quickly and prevent weeds
- Fill your window boxes with petunias that complement your home’s color scheme
- Try them in hayracks along a sturdy fence or in a DIY copper wire plant hanger
Last updated: March 11, 2020
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