How to Grow and Care for Snapdragons for a Burst of Color That Lasts From Spring to Fall

With varieties called Sonnet Yellow and Potomac Apple Blossom, is it any wonder that snapdragons bring a burst of color wherever they bloom? In addition to a far-ranging palette, true snapdragons also re-bloom vigorously, attracting beneficial insects. They're relatively easy to care for and deer resistant, plus, their whimsical beauty can add a touch of cottage charm to your garden.

Not only that, but according to Google, snapdragons are more popular than ever—especially in major cities like New York, London, and Berlin. Here, we spoke to experts to help guide you through their planting process, from the best practices for maintaining these plants to the common mistakes you should avoid. Follow these tips and tricks and you can enjoy snapdragon blooms from the earliest spring past the first frost. 

How to Grow From Seed

Snapdragons can survive winters as cold as 0 degrees Fahrenheit, but they can be tricky to germinate by direct seed—they prefer to be started indoors and then transplanted outside.

"In locations with mild winters, so zone 7 and above, you can start snaps in the fall and transplant out to overwinter," says Meredith Bishop, a specialty farmer and florist with Bloom & Bounty. "In colder zones, start seeds about six weeks before planting out in very early spring."

Start Indoors

Bishop finds snapdragons easy to start indoors, and her favorite method is to use a repurposed clamshell container and simply fill it with moistened organic seed starting mix.

"Avoid anything labeled 'potting mix,' which may contain large chunks of mulch on which a seed won't germinate," she says. "Sprinkle the tiny seeds on top and close the container to provide humidity. Snapdragon seeds need warmth and light to germinate, so place the container in a south-facing window or under grow lights and water gently every few days."

Choose the Right Container Size

Snapdragons should be started indoors regardless of where you intend to keep them in the end, says Bishop. Regardless, you should only choose hybrid varieties that reach just 1 or 2 feet in height to plant in containers. "Some traditional varieties of snaps can reach 4 feet or higher and would not be suitable for a container," she warns. 

Laura Janney, CEO of the Inspired Garden, also recommends sticking with a dwarf variety and giving extra attention on hot days. "Shorter varieties are cool, tolerant plants and are ideal for early spring," she says. "Keep your eye on containers, as they tend to dry out faster than the ground. Use moisture control soil in the summer."

Transplant

Seeds should germinate within seven to 10 days. After, thin the seedlings down so there's one planted every half inch or so and continue to grow until they have several sets of true leaves.

"At this point, I leave the clamshell container open to allow the seedlings to stretch upwards," says Bishop. "Once they're approximately 3 or 4 inches tall, they're ready to be transplanted out into the prepared garden bed."

How to Care for Snapdragons

Snapdragons are organized by group, says Bishop, with the first blooming from late winter into earliest spring. "For long-lasting displays of beautiful cut flowers throughout the year, choose varieties from each group," advises Bishop. "Popular ones include Chantilly, Potomac, Madame Butterfly, and Rocket."

However, keep in mind that snapdragons are usually hardy for only two years. "By year three, their stems are not as strong and they will produce less blooms," Janney says. "Make sure to invest in more seeds then."

Soil and Water 

Snapdragons will grow best in fertile soil that drains well. Regular watering is helpful for prolific blooms, especially during the warmest parts of the season. "Snapdragons get stressed in the heat, so make sure to keep them well watered during the hot months—and continuously deadhead and prune," Janney says. "Make sure to keep the soil consistently moist—but don’t overwater—while the plants get established."

Be vigilant during unusually warm days or a summer heatwave. "With extra watering, they should beat the heat," says Janney. "I recommend watering twice a day—both early morning and early evening—slowly around the stems." 

Sunlight

Snapdragons need full sun, according to Janney, but keep an eye on them during the summer. If your snapdragons overheat, they won't produce any blooms; additional watering can help them make it through the warmer months.

Fertilizer

Snapdragons aren't heavy feeders and don't require special fertilization, so long as the planting medium is nutrient-dense. "I like to amend my planting beds with organic compost or worm castings before transplanting into them, which will feed the blooms all season long," says Bishop.  

Once your snapdragons are close to maturing, Janney recommends a bloom booster—but be sure to follow the fertilizer's directions. 

How to Prune Snapdragons

Snapdragons are known as "cut-and-come-again" flowers, meaning the more you harvest or prune, the more blooms it will produce. "If you're not harvesting for arrangements, deadheading is very important in order to keep flowers coming," says Bishop. "Otherwise, the blossoms will be pollinated, and the annual plant will set seed and die back." 

Snapdragons will even reward you for a hard prune early in the planting season. "Once the seedling has grown to approximately 10 inches in height, cut back to right above a set of leaves, leaving three sets in total," says Bishop. "The plant will produce two dominant shoots where once there was only one, giving you twice the blooms."

Common Mistakes

One of the biggest mistakes Janney sees with snapdragons is incorrect placement in a garden. "Pay attention to the label. People don't realize how tall these plants can get," she says. "Place the taller varieties towards the back third of the garden, and the shorter ones in the front."

Another common mistake is failing to stake your plants. "Some varieties can grow upwards of 4 feet tall and can easily be knocked down by wind," Bishop says. "Once bent, they cannot be straightened and will grow toward the sun from their prone position." 

Last but not least, don't uproot the plants. "Let them go to seed when the growing season is over," Janney advises. "There's a good chance you'll be rewarded the following year."