How To Grow And Care For Snapdragons
These cool season annuals also make excellent cut flowers.
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Snapdragons (Antirrhinum majus) are cool season, annual flowering plants, also known as hardy annuals. They prefer cool temperatures to flower, such as early spring or a very mild winter. These flowers are called snapdragons because the individual 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 have been bred extensively. There are cultivars with traditional “snap” flowers, open-faced flowers, 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 an excellent cut flower and many cultivars have a pleasant fragrance.
Plant Attributes
Common Name: Snapdragon
Botanical Name: Antirrhinum majus
Family: Plantaginaceae (was in Scrophulariaceae)
Plant Type: Annual, Herbaceous
Mature Size: 6-48 in. tall, 3-12 in. wide
Sun Exposure: Full Sun
Soil Type: Moist but Well-Drained
Soil pH: Neutral Soil pH
Bloom Time: Spring, Fall
Flower Color: Red, Pink, Orange, Yellow, White
Hardiness Zones: 6-11 (USDA)
Native Area: Europe, Mediterranean
Snapdragon Care
Snapdragons are not native but have been naturalized and bred extensively for their flowers. They are flowering annuals that are grown outdoors in the garden in full sun. Because the plant size ranges from 6 to 48 inches, snapdragons can be used for rock gardens and containers to 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, if kept watered in the summer, they could bloom again in the fall. In the Lower South, Coastal South, and Tropical South, they will bloom in the winter and spring.
Snapdragon flowers are pollinated by bumblebees, and they attract hummingbirds. The individual florets are edible and can be used as a garnish. The plants are deer resistant.
Light
Snapdragons need full sun to bloom, at least 6 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 1 inch of water per week. To prevent fungal disease, water at the base of the plant, in the morning.
Temperature And Humidity
Snapdragons prefer cool temperatures for flowering: 40 degrees F during the night and 70 degrees F during the day. They can tolerate a light frost. They need average humidity.
Fertilizer
Depending on how they are used, they may need to be fertilized with a 10-10-10 fertilizer when blooming. For example, small plants in rock gardens will not need to be fertilized but tall plants grown for cutting may need fertilizer.
Types of Snapdragons
There are many types; the cultivars below were chosen to illustrate the wide variety in floral shape and color. The traditional “snap” or “dragon’s snout” are called mouth-shaped florets. There are other flowers that are more open, called butterfly; double petal type florets called azalea type; and ruffled petals.
Dwarf: 6 to 15 Inches Tall
Floral Showers: traditional mouth-shaped florets, variety of colors
Frosted Flames: traditional mouth-shaped florets, variety of colors with variegated ivory and green foliage
Magic Carpet: traditional mouth-shaped florets, variety of colors
Montego: traditional mouth-shaped florets, variety of colors
Snaptini: traditional mouth-shaped florets, variety of colors,
Twinny: butterfly type flowers, ruffled, very large florets, variety of colors.
Medium or Intermediate: 15 to 30 Inches Tall
Bridal Pink: pink florets that look double or ruffled
Liberty: traditional mouth-shaped florets, variety of 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 a variety of colors
Opus: florets have more ruffles, look fuller, different 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, variety of colors, lightly scented
Legend: traditional mouth shaped florets that are ruffled and large, variety of 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, variety of colors, fragrant
Trailing
Candy Showers: traditional mouth shaped florets, variety of colors\
Pruning
When the plant is about 4 inches tall, it can be pinched back to encourage side shoots to form for more blossoms. This is optional. If you intend to cut stems for cut flower production, pinching like this will delay the harvesting time.
How To Grow Snapdragons From Seed
For the Upper South and Middle South gardeners, start sowing seeds indoors under lights about 8 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 so the snapdragons can be planted in the garden by the end of November. The winters are mild enough for the plants to grow and bloom in winter and spring.
In clean seed starting trays (with drainage holes), add moistened seed starting mix. Sprinkle snapdragon seed on top or try to sow evenly with a moistened toothpick. The seeds are very fine and need light to germinate. Press seed onto the moisten mix for contact but do not cover with additional mix.
Place under grow lights or fluorescent tubes, leaving lights on for 14 to 16 hours per day.
The lights have to be adjustable. They should be only a few inches away from the plant.
It can take 2 weeks for seeds to germinate so be patient.
Mist with water frequently so seeds do not dry out. It is important that they do not dry out when they begin the germination process because germination will stop if allowed to dry and the seeds cannot be “revived.”
As the seed germinates and grow, may have to adjust lights to continue to be only a few inches away from the plant.
As the seedling grows, can water or mist less often because the roots have formed and are able to obtain water from a lower depth in the mix.
Thin the seedlings, which is to reduce the number in order 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.
When true leaves have developed and it is a few weeks away from average last frost, can transplant out to garden or container. Snapdragons can tolerate a light frost, so it is okay to plant outside one or two weeks before average last frost.
Continue to water to establish the plants.
Overwintering
Because snapdragons are treated as annuals, they are not “overwintered” or saved for the next year. When they are done for the season, they are cut at the ground level and removed. If they had been suffering from a disease, especially a fungal disease, they should be bagged and thrown away, not in the compost pile.
Common Pests & Plant Diseases
Snapdragons are prone to rust, specifically snapdragon rust; other fungal diseases such as anthracnose and botrytis blight; downy mildew; powdery mildew; stem rot and wilt; root rot; and viruses.
There is a specific rust called snapdragon rust caused by Puccinia antirrhini. Small yellow spots appear on the upper side of the leaves and rings of brown pustules 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. Diseased plants must be destroyed. To prevent, 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.
Snapdragons may be attacked by spider mites or aphids. 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 they 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 the cool temperatures to bloom so it is natural that they stop blooming during the summer. However, if they are cut back in the summer, and watered throughout the summer, they may re-grow and bloom again during fall’s cool temperatures.
Snapdragons need to be deadheaded to encourage a long blooming period. If allowed to go to seed, the plant will stop blooming. However, if allowed to set seed, some seed may germinate next year. Just remember that if the plant was a hybrid, it may 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 to understand that they prefer cool temperatures to flower. They are relatively common cool season annuals sold at the garden centers, along with pansies and ornamental kale and cabbages. Usually what is sold at the garden center are the dwarf to intermediate sizes in the traditional flower form (mouth like). One can obtain a wider variety if one grows from seed.
The snapdragons do not seem to be blooming
If the snapdragons are not blooming, it may be because there is not enough light. Snapdragons need at least 6 hours of sun to bloom.
The snapdragons were blooming but that seems to have stopped
If the snapdragons were blooming and now have stopped, it is likely that it is too warm, that is, temperatures are in the eighties and above. Keep the plant growing by continuing to water and encourage a second flush in cooler seasons by cutting the plant back.
The snapdragon leaves are unsightly with ugly spots
This is probably snapdragon rust (Puccinia antirrhinin), which is a fungal disease that thrives in the same cool temperatures as snapdragons. The rust usually does not kill the plant but to prevent further infection it is best to remove, bag, and throw away the plants (do not put in the compost pile). To prevent this from happening in the future, increase spacing among plants to increase air circulation, water at the base, not overhead, and water in the morning, not the evening.
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