Remember when you were a kid, and the bright colors of ribbon candy were almost as enticing as the simple, sweet taste? When it comes to filling your garden bed or containers, petunias are the ribbon candy of the horticulture world. Their cheerful brilliant colors and unpretentious simplicity make them a tempting choice.
We dug deep into the varieties, care, and versatility of this classic annual and found that, over the past couple of decades, horticulturalists have expanded the world of petunias, taking the little annual from basic to brilliant.
Petunia blossoms are usually a simple trumpet shape (some specimens are showier), and each plant will put out many blooms throughout the season. They’re what’s known as a tender perennial; in their native South America, the plants can survive multiple years, but in colder climates, they’re grown as annuals. They’re valued for the color they bring to containers, hanging baskets, window boxes, and garden beds – and different varieties are best suited for each place.
A rainbow of choices
Their colors are what’ll first catch your eye. Petunias can be solid or multicolored (the latter are usually bi-colored, but there are a few tri-colors). You’ll find petunias in shades of pink ranging from delicately tinted to fuschia, to everywhere in between. The flowers also come in a range of reds. Choose from fire-engine to deep, nearly burgundy shades.
In the yellow family, you’ll see buttery creams to sunny golden blossoms. There are orange and peach versions as well, so if you’re looking for a salmon flower or one that’s deeper orange, you’ll have some options. We also like the white and nearly-black blossoms, along with the striped, tie-dyed, and mottled multi-colored varieties.
But we’re really excited when petunias get the blues – even the most casual gardeners know it’s hard to find truly blue flowers, and several petunia hybrids now fit the bill, whether you’re out for a sky blue or a deeper, royally blue tone.
Okay, now the downside. While it’s true you can find a rainbow of colors when browsing seed catalogs, you won’t find quite as many options at your local garden center in seedling form. But that’s okay – most nurseries will still offer a good assortment of petunias because they’re both easy to grow and easy on the eyes.
You’ll likely be able to choose from pinks, reds, split colors, purple, and yellow – and you can always ask if they’re willing to explore some of the other varieties, or grow from seeds if you’re dead set on a specific hue. Burpee has a wonderful selection of petunia seeds and plants across the color spectrum, including Debonair Dusty Rose, a unique pink-to-yellow cultivar, and Starry Burgundy, which is spangled with little bursts of light. Some varieties stray so far from the classic trumpet shape and traditional colors that only their foliage will give them away as this once-humble flower!
Seeds or Seedlings?
If you decide to grow your petunias from seed, be warned: the seeds themselves are tiny, and coaxing the first couple inches of growth can be tricky. You’ll need a light seed-starting mix, planting trays, growing lights, and some patience. The seeds do best when you start them ten weeks earlier than planting time (check your zone for when you’re out of frost danger).
The seeds should be sprinkled right on top of the soil, sprayed lightly, and then covered with plastic wrap and kept in a warm spot. Once they sprout, you can remove the plastic and put the trays under the growing light. Water when the soil looks dry, and keep the temperature around 65 degrees.
Once the seedlings have three of their true leaves, you can transfer the strongest specimens to their own pots and keep them under the lights until they’re ready to be hardened off. On warm, bright days, put them outside, and then bring them in before temps drop at night. Once they’re toughened up, and there’s no danger of frost, the petunia seedlings are ready for life in the great outdoors.
A petunia for every purpose
Where that is depends on what variety you’ve chosen. Some petunias make great ground covers – they creep along close to the soil, putting out tendrils to cover up to three or four feet per plant. These varieties also do well in hanging baskets or in planters; they prettily escape the bounds of their containers to create a cascading effect. If you’re in the market for a ground cover or container petunia, be sure to check out the “Wave” series.
In addition to their low growing height and far-reaching tendrils, you don’t have to pull off the dead flowers to encourage new blooms. Still, if you’re looking to cover the ground underneath trees or in other shady regions of your property, you should bear in mind that spreading petunias require at least six hours of sunlight a day. Any less than that, and you’ll get poor performance. They thrive in full sun, so for the best show, give them a bright, sunny spot, and they’ll reward you with blooms all summer.
In addition to spreading petunia varieties, nurseries will offer grandiflora collections. These are the old-school large-flowered plants that grow up to 24 inches high and do well in containers or the garden. We love their big, showy flowers (some are up to five inches!), but the size can come at a cost – one heavy rainfall, and these delicate blossoms will collapse into a brown mush that will discourage new buds if it isn’t removed.
But deadheading is a labor of love if you value the sheer size and spectacle of these otherwise low-maintenance plants. Just plant the seedlings, pinch the tops off to promote bushy growth, and pay attention to deadheading, and they’ll lend loads of cheer to any sunny spot in your yard, whether it’s in a bed or as part of a container planting.
Multiflora petunias were genetically engineered to produce smaller, more profuse blooms than their big sisters. We prefer them to grandifloras when it comes to planting in beds because multifloras mound lower to the ground to create a more structured look (grandifloras can look leggy and even sparse in the heat of summer). Multiflora stems are sturdier as well as shorter, and the smaller flowers (about two inches wide) stand up better to rain. They grow to a height of about eight inches and are equally suited to containers as they are to borders.
In addition to these three broad classifications, you can also find floribunda cultivars. These combine the best aspects of grandiflora and multiflora; they’ll give you larger flowers that are a little more sturdy under rainfall. We like the Celebrity and the ever-popular Wave varieties.
Care and Feeding
No matter which variety and colors you choose, you’ll get the best performance from your petunias if you pay attention to their needs. They prefer lightweight, fertile soil with a pH between 5.5. and 6.5 (peat moss is a good way to add acid to soil). Plant your grandiflora and multiflora seedlings about a foot apart. Add six inches to that for spreading petunias.
The experts recommend frequent fertilization, as these plants grow fast, especially the spreading varieties. Keep the soil evenly moist – it’s very important to watch the moisture level in container plantings, as they dry out quickly in the summer heat. At the same time, make sure you don’t overwater, and check your containers after rainfall because water pooled around the petunia’s roots can cause rot.
Monitor your petunias for pests throughout the growing season, as they can be magnets for slugs and aphids. Deadheading is a great time to check under leaves and around the base of plants for these pesky critters. If your petunias are plagued by bugs, consider bait or light sprays.
With their relatively low maintenance and fast-growing capabilities, petunias have been a mainstay of borders and containers for generations – and these days, we can look to them for a rainbow of color all summer long.