Learn how to grow and fertilize Antirrhinum snapdragons for vibrant blooms. This guide covers planting, feeding schedules, and care tips for healthy flowers.
I’ll never forget the first time I showed my daughter how to gently squeeze the sides of a snapdragon flower to make its “dragon mouth” open and close. That magic, combined with their tall, vibrant spires of blooms, has made them a permanent fixture in my garden ever since.
Snapdragons (Antirrhinum majus) are cool-season annuals prized for their unique flowers that come in nearly every color except blue. With the right care, they can provide color from spring through fall, and in mild climates, they may even overwinter to bloom again.
Why Grow Snapdragons?
You should grow snapdragons for three key reasons. First, their distinctive flowers add vertical interest and a playful element to gardens and containers. Second, they are excellent as long-lasting cut flowers, often lasting over a week in a vase. Third, they are a favorite of pollinators like bumblebees, which are strong enough to pry the flowers open to reach the nectar.
A Quick Snapdragon Reference
| Aspect | Requirement |
|---|---|
| Common Name | Snapdragon |
| Botanical Name | Antirrhinum majus |
| Plant Type | Tender perennial, usually grown as an annual |
| Mature Size | 6-48 in. tall, depending on variety |
| Sun Exposure | Full sun to partial afternoon shade |
| Soil Type | Rich, well-draining soil |
| Bloom Time | Spring to fall; slows in peak summer heat |
| Hardiness Zones | USDA 7-11 as a perennial; annual elsewhere |
How to Plant Snapdragons
You can start snapdragons from seed or from young nursery transplants. Transplants give you a head start, especially if you want early spring blooms.
Starting from Seed
Sow seeds indoors 8 to 10 weeks before your last expected spring frost. Press the tiny seeds lightly onto the surface of moist seed-starting mix, as they need light to germinate. They typically sprout in 10-14 days. After the danger of frost has passed and seedlings have several sets of true leaves, you can harden them off and plant them outdoors.
Planting Transplants
Choose a location with at least 6 hours of sun. If you live in a region with hot summers, a spot with afternoon shade will help them bloom longer into the summer. Work compost into the soil before planting to improve drainage and fertility. Space plants according to their mature size, typically 6 to 12 inches apart.
How to Fertilize Snapdragons for Maximum Blooms
Feeding your snapdragons correctly is the key to a long and spectacular bloom show. They are not heavy feeders, but they do benefit from consistent nutrition.
At Planting Time
Begin by preparing the soil. Mix a balanced, slow-release fertilizer into the soil at the time of planting. Look for a granular formula with a balanced NPK ratio, such as 10-10-10 or 14-14-14. This provides a steady supply of essential nutrients to get your young plants established. Alternatively, you can mix in a generous amount of well-rotted compost, which feeds the plants and improves soil structure.
During the Growing Season
Once your snapdragons begin to form flower buds, it’s time to switch to a fertilizer that supports blooming. Use a water-soluble fertilizer that is higher in phosphorus (the middle number in the NPK ratio). A formula like 10-20-10 or 15-30-15 is ideal.
Apply this bloom-booster fertilizer every 4 to 6 weeks throughout the growing season. I always follow the label instructions for dilution rates, as over-fertilizing can lead to more leaves than flowers. For more on nourishing flowering plants, see our guide on flower gardening.
Ongoing Care for Healthy Plants
- Watering: Keep the soil consistently moist but not soggy. Water at the base of the plant to keep the foliage dry and prevent disease. Snapdragons prefer about an inch of water per week.
- Deadheading: This is the most important task for keeping your snapdragons in bloom. As the individual flower stalks finish blooming, use clean pruners or your fingers to snip the entire stalk back to the first set of leaves. This encourages the plant to send up new flower spikes from the base.
- Pinching: When young plants are about 4-6 inches tall, pinch off the top inch of the main stem. This encourages branching and results in a bushier plant with more flower spikes.
Common Problems and Solutions
- Rust: This fungal disease appears as orange or brown pustules on the undersides of leaves. Prevent it by watering at the base, providing good air circulation, and choosing rust-resistant varieties. Remove and destroy infected leaves.
- Aphids: These small, soft-bodied insects cluster on new growth and flower buds. You can often control them by spraying the plants with a strong stream of water or using an insecticidal soap.
- Leggy Growth: This is usually caused by insufficient sunlight or overcrowding. Make sure your snapdragons get enough sun and are spaced properly. The Royal Horticultural Society offers excellent advice on preventing common growth issues.
- Few Blooms: The most common causes are not enough sun, over-fertilizing with nitrogen, or failing to deadhead. Ensure your plants get plenty of light, use a bloom-booster fertilizer, and regularly remove spent flowers.
Tips for a Continuous Bloom Show
For the best performance, treat snapdragons as a cool-season flower. In hot summer regions, they often stop blooming. You can cut them back by about one-third, keep them watered, and they will often reward you with a fresh flush of blooms when cooler weather returns in the fall.
Snapdragons are versatile enough for garden beds, borders, and containers. Their spiky form provides a wonderful contrast to mounding plants like petunias or trailing plants like lobelia. For more ideas on designing with flowers, check out our container gardening guide.
I hope this guide helps you grow a stunning display of these charming flowers. Have you found a favorite snapdragon variety? I’d love to hear about it in the comments.
