How To Grow And Care For Snapdragons

Snapdragons (Antirrhinum majus) are cool-season, annual flowering plants known as hardy annuals. They prefer cool temperatures to flower, such as early spring or mild winter. Snapdragons get their name because the flowers' florets resemble a dragon's snout. Children enjoy squeezing the florets to separate the top from the bottom, like opening the dragon's jaw. Easy to grow from seed, snapdragons proliferate extensively. 

Cultivars have traditional "snap" flowers, open-faced or double flowers in all colors except for blue. Heights range from dwarf (6-15 inches) to intermediate (15-30 inches) to tall (30-48 inches). Snapdragons can be grown in rock gardens, containers, hanging baskets (especially the trailing varieties), or in the garden. They make excellent cut flowers, and many cultivars have a pleasant fragrance.

Plant Attributes

Snapdragon Care

Snapdragons are not native but have been naturalized and bred extensively for their flowers. They are flowering annuals grown outdoors in the garden in full sun. Because the plant size ranges from six inches to four feet, use snapdragons for rock gardens and containers for beds devoted to cutting flowers.

These are cool season annuals. In the Upper and Middle South, they will bloom in the spring and stop blooming in the summer. However, they could bloom again in the fall if kept watered in the summer. In the Lower South, Coastal South, and Tropical South, they will bloom in the winter and spring. 

Bumblebees pollinate snapdragon flowers, and they attract hummingbirds. The individual florets are edible (used as a garnish). The plants are deer resistant.

Light

Snapdragons need full sun to bloom, at least six hours a day.

Soil

They require moist but well-drained soil high in organic matter.

Water

These plants need water to germinate and to get started. Still, as established plants, they will need slightly moist soil—about one inch of water per week. To prevent fungal disease, water the plant base in the morning.

Temperature And Humidity

Snapdragons prefer cool temperatures for flowering: 40°F during the night and 70°F during the day. They can tolerate a light frost. They need average humidity.

Fertilizer 

Depending on their use, they may need to be fertilized with a 10-10-10 fertilizer when blooming. For example, small plants in rock gardens will not require fertilization, but tall plants grown for cutting may need fertilizer. 

Types of Snapdragons

There are many types of snapdragon cultivars. The following varieties illustrate the wide variety of floral shapes and colors. The traditional "snap" or "dragon's snout" is mouth-shaped florets. Other "butterfly" flowers are more open, with double-petal florets and ruffled petals called azalea type.

Dwarf: 6 to 15 Inches Tall

• Floral Showers: traditional mouth-shaped florets, various colors 
• Frosted Flames: traditional mouth-shaped florets, various colors with variegated ivory and green foliage
• Magic Carpet: traditional mouth-shaped florets, various colors 
• Montego: traditional mouth-shaped florets, various colors 
• Snaptini: traditional mouth-shaped florets, various colors,
• Twinny: butterfly-type flowers, ruffled, very large florets, various colors

Medium or Intermediate: 15 to 30 Inches Tall

• Bridal Pink: pink florets that look double or ruffled
• Liberty: traditional mouth-shaped florets, various colors 
• Lucky Lips: traditional mouth-shaped florets and large, dark rose/cream bicolor flowers
• Madame Butterfly: double-petal-type florets that also are called azalea-type, very fluffy florets in various colors
• Opus: florets have more ruffles and appear fuller with various colors
• Night and Day: traditional mouth-shaped florets and large, dark crimson and white bicolor flowers, very dark foliage 

Tall: 30 to 48 Inches Tall

• Chantilly: open face floret shape, also called butterfly, various colors, lightly scented
• Legend: traditional mouth-shaped florets, ruffled and large, various pastel colors, including Light Pink, which is a unique lavender pink color
• Maryland Plumblossom: traditional mouth-shaped florets that are pink/purple and white bicolor
• Potomac: traditional mouth-shaped florets, different colors including Potomac Appleblossom, which is a pale pink and cream white, bicolor
• Rocket: traditional mouth-shaped florets, various colors, fragrant

Trailing

Candy Showers: traditional mouth-shaped florets, various colors

Pruning

When the plant is about four inches tall, pinch it back to encourage side shoots to form more blossoms. This pruning is optional. Pinching like this will delay the harvesting time if you intend to cut stems for cut flower production.

Propagating Snapdragons

Snapdragons propagate quickly from cuttings and root division. Here is how to propagate snapdragons from cuttings:

1. First, take cutting from a healthy snapdragon in the summer—around six weeks before the first frost. Check your local area for expected frost dates. 
2. Choose a selection with foliage still attached. 
3. Dip the cutting into a rooting hormone to help it take root. 
4. Plant the cuttings in potting soil. Keep the soil moist and maintain healthy air circulation throughout the winter. 
5. Roots will establish throughout the winter. Transplant healthy snapdragons outside in the spring after the final frost passes.

How To Grow Snapdragons From Seed

For Upper and Middle South gardeners, start sowing seeds indoors under lights about eight weeks before the average last frost. The plants will bloom in the spring and early summer. For the Lower South, Coastal South, and Tropical South gardeners, sow the seeds at the end of September to plant snapdragons in the garden by the end of November. The winters are mild enough for the plants to grow and bloom in winter and spring.

1. Add moistened seed starting mix in clean seed starting trays (with drainage holes). Sprinkle snapdragon seed on top or sow evenly with a moistened toothpick. The seeds are very fine and need light to germinate. Press the seed onto the moistened mix for contact, but do not cover it with a different mixture.
2. Place under grow lights or fluorescent tubes, leaving lights on for 14 to 16 hours daily.
3. The lights have to be adjustable. They should be only a few inches away from the plant. 
4. It can take two weeks for seeds to germinate, so be patient.
5. Mist with water frequently so seeds do not dry out. They must not dry out when germination begins because germination will stop if allowed to dry, and the seeds cannot be "revived."
6. As the seed germinates and grows, you may have to adjust the lights to remain only a few inches away from the plant. 
7. As the seedling grows, you can water or mist less often because the roots have formed and can obtain water from a lower depth in the mix. 
8. Thin the seedlings to reduce the number to create space for the rest. Cut the weakest seedlings with nail or manicure scissors at the base—This will make room for the strongest. Best to cut, do not pull seedlings out, as this will disrupt the rest of the seedlings. 
9. When true leaves have developed, a few weeks away from the average last frost, they can transplant into a garden or container. Snapdragons can tolerate a light frost, so it is okay to plant outside one or two weeks before the average last frost. 
10. Continue to water to establish the plants.

Overwintering

When treating snapdragons as annuals, it is unnecessary to "overwinter" the plants or save them for the following year. When done flowering for the season, cut them at the ground level and remove them. If the flowers suffer from a disease, especially a fungal infection, bag and throw them away, not in the compost pile. 

Common Pests & Plant Diseases

Snapdragons are prone to rust, specifically snapdragon rust. Other fungal diseases include anthracnose and botrytis blight, downy mildew, powdery mildew, stem rot, wilt, root rot, and viruses.

Snapdragons suffer from specific rust caused by Puccinia antirrhini. This rust causes small yellow spots to appear on the upper side of the leaves and rings of brown pustules to appear on the underside of the leaves.

Unfortunately, Puccinia prefers the same cool temperatures as snapdragons. The rust usually does not kill the plant but will make it unsightly, and you must destroy the diseased plants. To prevent this, increase spacing among plants to increase air circulation, plant from seed, water at the base, not overhead, and water in the morning, not the evening. 

Spider mites or aphids may attack snapdragons. Aphids are tiny insects that suck the plant's nutrients from the foliage, thus weakening the plant and making it unsightly. Aphids also excrete a sticky substance called honeydew, which attracts sooty mold and can transmit viruses. To control aphids, spray with insecticidal soap. 

Spider mites are tiny spider-like mites that also suck nutrients from the foliage. It is easier to see their webs under the leaves. They weaken the plant and create specks on the leaves or cause the foliage to be a lighter yellow. To control spider mites, spray with insecticidal soap.

How To Get Snapdragons To Bloom

Snapdragons need cool temperatures to bloom, so it is natural that they stop blooming during the summer. However, if cut back and watered throughout the summer, they may re-grow and bloom during fall's cool temperatures. 

Deadhead snapdragons to encourage a long blooming period. If allowed to go to seed, the plant will stop blooming. However, if allowed to set seed, some seeds may germinate next year. Just remember that if the plant was a hybrid, it might not come back true to form.

To deadhead, notice that the flowers start opening at the bottom of the flower spike first, so remove those spent flowers first. Or just cut the entire flower head when blooms are past their prime but cut at the base of the plant.

When cutting the flowers for the vase, cut when a few florets have opened at the bottom, and the top buds are still closed. Cut the stem at the base, near the ground. Strip the lower leaves. Cut snapdragons last several weeks. 

Common Problems With Snapdragons

The trick to growing snapdragons is understanding that they prefer cool temperatures to flower. They are relatively common cool-season annuals sold at garden centers, along with pansies, ornamental kale, and cabbages. Usually, snapdragons sold at the garden center are dwarf to intermediate sizes in the traditional flower form (mouth-like). One can obtain a wider variety if one grows from seed.

Flowers Not Blooming

If the snapdragons are not blooming, it may be because there is insufficient light. Snapdragons need at least six hours of sun to bloom.

Blooming Stopped

It is likely too warm if the snapdragons were blooming and now have stopped—temperatures in the eighties and above. Keep the plant growing by continuing to water it and encourage a second flush in cooler seasons by cutting it back. 

Browning Tips

This issue is probably snapdragon rust (Puccinia antirrhinin), a fungal disease that thrives in the same cool temperatures as snapdragons. The rust usually does not kill the plant, but remove, bag, and throw away the plants (do not put them in the compost pile) to prevent further infection. To prevent this, increase spacing among plants to increase air circulation, water at the base, not overhead, and water in the morning, not the evening.