What to Know about Firefly Petunias
Firefly petunias glow in the dark, thanks to genetic engineering (the genes come from bioluminescent mushrooms). Here's how to grow them in your backyard or living room.
Light.Bio
Glow-in-the-dark petunias take center stage on a starlit night. In larger containers, use more than one plant to create a stunning display.
Make your yard the talk of the block by tucking Firefly petunias into your outdoor spaces. A typical white petunia by day, as dusk arrives this annual radiates a soothing green glow. Light Bio, the company behind this glowing petunia, describes the light show as similar to moonlight.
The gleaming genes responsible for the Firefly petunia’s nightly display come from bioluminescent mushrooms. Once added to petunia cells, these genes work with the plant’s natural chemistry to produce compounds that glow. In fact, Firefly petunias glow 24-7—the bioluminescence is simply easier to see after dark. Because the plant’s natural growth processes produce the glowing compounds, Firefly petunias don’t need any special treatment to shine.
Firefly Petunia Basics
Botanical name: Petunia x atkinsiana ‘Firefly White’
Common Name: Firefly petunia
Special features: Leaves, flower buds and flowers glow in the dark
Plant Type: Annual
Size: Grows 6 to 10 inches tall and 8 to 10 inches wide
Light.Bio
In daylight, Firefly petunia looks like any other white petunia. As dusk arrives, the bioluminescence becomes visible.
What Is the Firefly Petunia?
“Firefly is known as a Milliflora type of petunia,” says Susie Raker, Vice-President of Raker-Roberta’s Young Plants, the company that produces the plant. “Expect Firefly to grow compactly, forming a tidy mound covered with many small flowers.”
The research that fuels Firefly petunias’ shimmering show has been taking shape since the 1980s. One of the scientists behind the bioengineered plant is Keith Wood, who is now CEO of Light Bio, the company that’s bringing glow-in-the-dark plants to gardens everywhere.
Firefly petunia is a first-generation plant. “It’s the forerunner of a new plant class, and I’m expecting new color additions in the future, along with other different glowing varieties,” says Vaughn Fletcher of Fletcher Consulting, a veteran horticulturist with more than 50 years in the garden industry.
Light.Bio
Every part of Firefly petunia glows in the dark, with the strongest light visible in new growth, including stems, leaves, blossoms and flower buds.
How to Grow Firefly Petunias
The secret to raising Firefly petunias is maintaining a healthy plant. The bioluminescence is strongest in new flower buds, so keeping the plant healthy and producing new growth ensures a brightly glowing display. Here are the conditions Firefly petunias need to thrive.
Soil—Plant Firefly petunia into well-drained soil. In containers, choose a commercial potting mix with peat moss or coco fiber.
Temperature—Like all petunias, Firefly thrives in summer. Plant it outdoors in spring when night temperatures stay above 40° F.
Light—Give Firefly petunias full sun (6 to 12 hours of sun daily). In warmest growing zones, provide shade during the hottest part of the day.
Water—“Firefly thrives when soil is kept evenly moist, not too wet or too dry,” Susie shares. “The most common problem gardeners encounter with it is overwatering.”
Fertilizer—Keep Firefly petunias nourished to ensure a steady supply of new growth. Vaughn adds a slow release fertilizer like Osmocote to soil at planting time, following with a liquid fertilizer every two weeks. Susie recommends Jack’s Petunia FeED or Miracle-Gro plant food.
Pruning—If flowers become sparse, lightly trim stems to promote branching.
Petunia Flowers: Planting and Caring for Petunias
Easy-care petunias can't get enough of the sun. Learn how to grow petunia flowers in pots, hanging baskets or beds for vibrant summer color and get tips on how to care for wilting petunias.
Light.Bio
One of the best ways to enhance Firefly petunia’s glowing power is by grouping plants together, like in this greenhouse where many of the plants are produced for sale.
How to Use Firefly Petunias
Plant In Containers
One of the best ways to showcase Firefly petunias is in containers. “It truly shines in pots and hanging baskets,” Susie says. “Keeping it elevated and close to you makes it easier to enjoy its glow in daily life.”
Vaughn suggests using pots at least 14 inches across. “The larger container with more soil volume provides greater water retention and less root heat stress, which enhances plant performance,” he says. He thinks mass planting is the way to create the most eye-catching scene after dark.
This year Vaughn plans to put three Firefly petunias in 22-inch pots, pairing them with a medium height salvia or Angelonia as a thriller and additional spillers for accent. For a single Firefly plant, Susie recommends using a 6-inch-wide pot.
Place In Dark Areas
She recommends placing it in darker or shadowy spots, where it can create magical moments. “The best spots are areas free from bright lights, like streetlights or landscape lighting. It’s also a standout in moon gardens, where its bioluminescence really makes the space come alive after dark,” she adds.
Growing Firefly Petunias Indoors
Firefly petunia adapts readily to inside spaces, allowing you to savor the show up close. “Firefly doesn’t need any ‘charging’ to glow, but does require proper sunlight or grow lights to stay healthy and vibrant,” Susie says. Some gardeners report good results by placing Firefly petunias in a very bright south-facing window.
Where to Buy Firefly Petunias
Plants are available from local greenhouses and garden centers. The easiest way to find Firefly petunia is using the retail locator on the Light.Bio website. Or do an online search for the plant to find ways to order it for home delivery.
FAQs for Firefly Petunias
Does Firefly petunia have an impact on pollinators? “Pollinators such as bees and butterflies visit Firefly as much as they do any white petunia,” Susie shares. “The floral scent and flower structure are what attract pollinators, not the glow.”
Should you deadhead Firefly petunias? Flower buds glow the brightest, with the intensity slowly fading as blooms age. “Regularly removing spent flowers ensures the plant keeps producing new, radiant blooms throughout the growing season,” Susie explains.
Does Firefly petunia pose an environmental threat? The type of petunia used to create Firefly isn’t native to North America and isn’t considered an invasive plant. The chance that the modified genes can spread to native plants and unsettle ecosystems is minimal.
What’s a common mistake when growing Firefly petunias? “Not being patient enough to enjoy the glow. Your eyes need around 8 to 15 minutes to adjust to the dark so you can fully appreciate the bioluminescence,” Susie says. “It’s worth the wait!”
