Petunia × hybrida
If you held a flower popularity contest, petunias would certainly come away with a prize. Beloved for their masses of colorful blooms and their easy-care nature, these plants are a South American native that has definitely found a home in North America.
Gardeners appreciate the petunia’s multi-hued utility — it’s lovely as a specimen plant, in mass bedding plantings, or particularly in containers, with bloom-laden stems trailing over the sides of pots.
With single or double trumpet-shaped blooms in pink, purple, red, yellow, or white, this flower is often called upon to add vibrancy to the garden from spring until fall.
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Let’s learn more about this classic, fragrant beauty!
A Quartet of Types
The grandiflora types have large flowers — 3 to 5 inches across — and can grow to 10 to 12 inches tall.
Multiflora petunias have more abundant, smaller, 1- to 2-inch, flowers. This type will grow to be about 8 inches tall.
The compact milliflora types produce generous quantities of small flowers 1 to 1 1/2 inch in diameter. Millifloras are often used as edging plants or mixed with other annuals in containers.
Groundcover petunias only reach about six inches tall, and quickly spread to cover a large area in one growing season. They are often covered in so many flowers that you can barely see the foliage.
Grown as annuals in most of the United States, these plants may overwinter in zones 9-11. In fact, according to the University of Florida Institute of Food and Agricultural Sciences, the best time to plant petunias in the Sunshine State is in October and November.
Ride the Wave or Pick a Winner – Where to Buy
If you’re brave and want to try growing these from seeds (more on this in a minute), the grandiflora ‘Daddy’ series is very popular, and you can find pelleted seeds from True Leaf Market.
This package contains 1000 seeds that produce 12- to 15-inch plants with 4-inch ruffled blooms in a variety of colors with an attractive veined pattern. Available in blue (which looks to us like more of a purple than a true blue), orchid, pink and white “peppermint,” multicolored “sugar,” pink, red, and a mix of several colors.
In 1995 the Ball Seed Company introduced its ‘Wave’ series of cultivars, and these are among the most popular varieties available. The company has since broadened its line to include Tidal Waves, Double Waves, Easy Waves, and Shock Waves.
Get your own wave started with seeds for the Double Wave ‘Blue Velvet’ cultivar, available from JDR Seeds via Amazon.
You’ll get 100 seeds for spreading plants that produce gorgeous, deep purple, frilly flowers.
If you’re looking for live seedlings, Proven Winners will ship a four-pack of live ‘Supertunia Vista Silverberry’ plants, available via Amazon.
This award-winning, vigorous plant has white flowers with bright pink veins.
Seeds or Starts?
Like the wax begonia, petunias can be tricky to grow from seed. The tiny seeds have a very long germination period and quite specific requirements.
Fortunately, it’s generally very easy to find starts at garden stores. You’ll want to wait until the soil is at least 60°F and all danger of frost has passed before you transplant seedlings outdoors.
Situate these plants so they’ll get five or six hours of full sun. They’re not particularly choosy about soil, as long as it drains well.
Water, Food, and Neem Oil
In general, water petunias deeply about once a week. The plants may require more frequent waterings in drought conditions, of course. And remember to water the spreading varieties and those in containers more often.
Apply a balanced fertilizer, such as 10-10-10, once a month throughout the growing season. Double-flowered cultivars may require additional feedings.
If your plants stop flowering or become leggy, prune the shoots back to about half their length, feed with a liquid fertilizer, and water well.
At one ounce per gallon of water, this 16-ounce concentrated product will yield 16 gallons of treatment.
Liquid Bt can also be used to control caterpillars. If you spot them munching leaves and leaving black dots of frass scattered around, mix up a solution of Bacillus thuringiensis and water in a spray bottle according to package directions, shake, and spray onto the plants.
We like Safer Brand Caterpillar Killer Concentrate, and it is also available on Amazon.
A Popular Plant with Punch
Exciting new cultivars bring the popular petunia into the realm of modern landscape additions.
Mix and match eye-popping colors to create a carpet of floral beauty in your garden. Water thoroughly once a week, give them a little food once a month, and you’ll be rewarded with beauty all summer long.
Have you grown petunias? Which are your favorites? Tell us in the comments section below. And if you’re looking for other popular annuals, consider painted daisy.
Product photos via True Leaf Market, JDR Seeds, Proven Winners, Garden Safe, and Safer Brand. Uncredited photos: Shutterstock.
About Gretchen Heber
A former garden editor for a daily newspaper in Austin, Texas, Gretchen Heber goes through entirely too many pruners and garden gloves in a year’s time. She’s never met a succulent she didn’t like and gets really irritated every 3-4 years when Austin actually has a freeze cold enough to kill them. To Gretchen, nothing is more rewarding than a quick dash to the garden to pluck herbs to season the evening meal. And it’s definitely time for a happy dance when she’s able to beat the squirrels to the peaches, figs, or loquats.