How to Grow and Care for Snapdragon Plants

Snapdragon flowers
Ian Lee/flickr/CC By 2.0

Bright snapdragon flowers bloom profusely throughout cool weather in intensely saturated colors and are real standouts in either the spring or fall garden. The flowers start blooming at the bottom of the stalk and work their way up, making for a long period of bloom.

Although snapdragons tend to stop blooming in heat of mid-summer, if you keep them watered, they will perk up and carry your garden through fall. The plants are undemanding and come in a wide selection of colors and heights.

Their botanical name, Antirrhinum, means "like a snout" and refers to the seed pod's resemblance to a calf's nose. How do such charming flowers wind up with such ungracious names?

The common names all derive from the way the flowers resemble opening mouths when they are pressed on their sides. The openings of the flowers are snapped tightly shut and require more pressure to open than a honeybee can provide, so snapdragons rely on heavier bumblebees for their pollination.

  • Leaves: The alternate, lanceolate leaves are arranged in a spiral around the stem.
  • Flowers: The flowers come in just about every shade, except true blue. Some are vibrant bold tones, some are soft pastels and some are subtly shaded bi-colors.

CAUTION: All parts of snapdragon are poisonous if ingested.

Botanical Name

Antirrhinum majus

Common Names

Snapdragon, Dog's Mouth, Lion's Mouth, Toad's Mouth

Hardiness Zones

Snapdragons are tender perennials that are only hardy to about USDA Hardiness Zones 8 or 9. In most areas, they are commonly grown as annuals. Even when they do over-winter, they never seem to bloom as robustly as they did in their first year, which leads many people to think they are biennial. However, they should form seed pods in their first year. If you are lucky, they may even self-sow.

Sun Exposure

Your snapdragons will bloom most profusely in full sun to partial shade, in the spring. Once the temperature heats up, they may stop blooming altogether. Planting them in partial shade and keeping them well watered will help them make it through the summer, to begin blooming again in fall. However, they are quick to get established and it can be just as easy to replace your snapdragon plants each season.

Mature Plant Size

There are tall varieties and dwarf varieties and just about everything in between. Check the label or packet of the variety you are choosing.

Dwarf plants mature at a height of about 6 - 15 inches and form dense, bushy plants with lots of flower stalks.

Tall varieties tend to be less bushy and spikier in habit, reaching a height of 30 - 48 inches.

Some varieties bridge the two extremes, growing to a mid-sized 15- 30 inches. Of course, the actual size and fullness of the plants will also depend on growing conditions.

Snap dragon by fence
Thang Tat Nguyen / Getty Images

Bloom Period

Snapdragons are at their best in cool weather. They can repeat bloom throughout the season but do best in the cool of spring and fall and throughout the winter, in mild climates. Deadheading can increase the number of buds that are set, but since the flower stalks begin blooming from the bottom up, they have a fairly long bloom duration anyway.

Tips for Growing Snapdragons

Soil: Snapdragons like a neutral soil pH, between 6.2 and 7.0. As short-lived plants, they are not heavy feeders, but adding organic matter will help keep them healthy and blooming.

Planting: Snapdragons can be winter sown, meaning you can toss the seeds out in late fall or even on top of snow, and most will germinate in the spring.

However, snapdragons are most often either started indoors, 8 - 10 weeks before the last frost date, grown from cuttings or purchased as seedlings. When starting from seed, simply press the seed on the surface of the potting soil. Snapdragon seeds need light to germinate.

When seedlings have developed about 6 true leaves, pinch the top of the stem off, to encourage branching and a fuller plant. You can do this with purchased seedlings too.

Transplant snapdragons outdoors a couple of weeks before your last frost date. Snapdragons can handle a light frost or two.

Caring for Snapdragon Plants

Regular deadheading will keep your snapdragons blooming longer. They won't need much care early in spring, but mulching to keep the soil cool and moist can help them handle summer better.

Some of the taller varieties will need staking unless they are planted close enough to other plants to lean on them.

Snapdragons are tender perennials and may die off in colder climates. If they do survive the winter, prune them back by about 1/3, to encourage new growth. Don't be too disappointed if they don't last long. Snapdragons tend to go downhill after their first year and it's best to start fresh every year. Many varieties will self-seed and come back on their own, although as hybrids, they won't always look like the original plants you planted.

Mid section of woman selecting snapdragons (antirrhinum) from flower farm field
Kinzie Riehm / Getty Images

The Best Snapdragon Varieties to Grow

They are continually coming out with new Snapdragon series. Most are sold as multi-color blends, but you can sometimes find individual colors in both seed and seedling. Some of the more popular series include:

  • Arrow™ Formula Mix - Vivid colors on strong, branching stems. Grows 2 ft.tall.
  • La Bella Mix - A nice blend of colors from pale to bronze to deeply saturated. Grows 12 - 18 inches tall.
  • Rocket Mix - A dependable multi-colored series that grows to about 2 - 3 ft. tall.

Using Sampdragons in Your Garden Design

Their spiky, bright colored flower stalks make a nice foil for the cooler shades of most spring flowers, like Brunnera and Bleeding Heart. Planted in clusters, they can help a border transition from the spring ephemerals to peak hot season.

The pale yellow varieties are the easiest to blend into a mixed border and work nicely with pinks, purples, and even reds.

Breeders have been playing with snapdragons for a few years now and there are trailing and creeping varieties becoming more widely available. These are great filler plants for containers, baskets and tucked into walls.

Pests and Problems of Snapdragons

Snapdragons are affected by few pests or diseases. Rust and other fungal diseases can be a problem, especially in wet seasons. If you live in a damp or humid area, look for resistant varieties. Snapdragons may also attract aphids.