Snapdragons are the flower that children remember: squeeze the sides of a bloom and the dragon's mouth opens and snaps shut. Beyond the charm, they are superb garden flowers — tall spikes of blooms in almost every colour, flowering from spring into summer, and one of the best cut flowers you can grow from seed.
Snapdragons are cool-weather plants, and they are hardy enough to be sown in autumn in mild zones or in early spring in cold ones. They flower best before summer heat arrives, and in mild climates they can flower through winter. Start them indoors for the earliest blooms, because the seeds are tiny and the seedlings are slow at first, but once they are growing they are tough and long-flowering.
Snapdragons at a glance
| Growing factor | What snapdragons need |
|---|---|
| Sun | full sun |
| Soil pH | 6.0–7.0 |
| Days to germination | 7–14 |
| Days to maturity | 80–90 |
| Spacing | 6–12 inches apart |
| Water needs | moderate |
| Cold tolerance | hardy |
| Family | Plantaginaceae |
Starting seeds
Snapdragons need a head start indoors — sow under cover and transplant out only after the last frost. Start seeds indoors a few weeks before your last frost date: in Zones 3–5 that means sowing in late winter, in Zones 6–8 early spring, and in Zones 9–10 late winter to very early spring. Zones 11–13 are frost-free, so indoor sowing can happen almost any time, with the cooler months giving the strongest plants; confirm exact timing with your local extension service. Seeds germinate in 7–14 days in warm, moist seed mix. Use clean trays or modules, a fine seed mix, and a bright windowsill or grow lights — leggy seedlings are almost always a light problem, not a seed problem. Harden seedlings off for a week before planting out, moving them outside for lengthening spells each day. Our seed starting calculator works out your indoor sowing date, and the grow light calculator checks whether your setup is bright enough.
Transplanting and planting out
Transplant seedlings out after the last frost, on a cloudy day or in the evening so they do not wilt in the sun. Space plants 6–12 inches apart — that spacing is what keeps air moving and disease down — and water each plant in well. Our plant spacing calculator works out exactly how many plants fit your bed, and the square foot garden planner helps lay them out.
Soil and feeding
Snapdragons grow best in fertile, well-drained soil with a pH of 6.0–7.0. Dig in compost before planting — it feeds the soil and helps it hold moisture without getting soggy — and mulch after planting to keep the roots cool and the weeds down. Feed during the growing season with a balanced fertiliser at the label rate, roughly once a month while plants are actively growing, and stop feeding as the season ends. Our fertiliser calculator works out the right amount for your bed, and the compost ratio calculator helps you make good compost to dig in.
Watering
Snapdragons have moderate water needs: keep the soil evenly moist while plants are establishing and flowering, and water deeply rather than little and often so the roots grow down. Water at the base in the morning so the foliage dries during the day, mulch to hold moisture in, and watch for wilting in hot, dry spells. Our watering calculator gives a starting point for your bed size, and the watering schedule generator can build a routine around it.
Sunlight and temperature
Snapdragons need full sun — at least six hours of direct sun a day. Snapdragons are hardy and tolerate frost and cold weather well, so they can be planted out earlier and left in the ground over winter in most zones. In frost-free Zones 11–13, heat and a lack of winter chill can limit performance, so give them the coolest spot you have. Check your zone with the hardiness zone finder before choosing varieties. Our sunlight calculator can check whether your spot gets enough sun.
Pests and diseases
The pests and diseases to watch for on snapdragons are aphids, slugs, cutworms. Aphids can cluster on shoot tips, slugs may eat young seedlings, and cutworms can cut young plants at the base. Snapdragons are also prone to rust in damp conditions, so good air flow matters. Check plants weekly, looking under leaves as well as on top, and act early. Hand-pick larger pests, knock aphids off with a strong spray of water, and remove badly affected leaves. Keep the area weed-free and avoid wetting the foliage when you water, since damp leaves invite fungal disease. Our pest identifier helper can help identify what you are seeing, and the plant disease checker helps narrow down leaf and stem problems.
Companion plants
Good companions for snapdragons are lavender, marigolds, garlic, chives. Lavender, marigolds, garlic and chives are good companions, and snapdragons pair well with pansies and spring bulbs for a cool-season bed that flowers for months. Our companion planting finder can suggest more pairings for your bed plan.
Harvesting
Cut snapdragons for the vase when the bottom third of the flower spike is open — the buds above will open in water over the next few days, and a spike lasts a week or more. Cut in the morning and put stems straight into water. Deadhead spent spikes to keep the plants blooming, and cut the main stem back by a third after the first flush: the plant will branch and flower again. Leave a few spikes to set seed if you want them to self-sow. Our harvest date calculator can estimate your picking date from your sowing date, and the vegetable yield estimator helps you work out how much a bed will produce.
Common problems and fixes
| Problem | Likely cause | Fix |
|---|---|---|
| Rust on leaves | fungal disease in damp conditions | Improve air flow, water at the base, and remove affected leaves. |
| Seedlings cut at the base | cutworms | Use a collar around seedlings and check the soil at night. |
| Plants stop flowering in summer | heat | Grow snapdragons for spring and autumn, and cut back after the first flush. |
Rust on leaves
Snapdragon rust shows as brown pustules on the undersides of leaves, and it spreads fast in damp, still air. Water at the base in the morning, space plants at the 6–12-inch spacing in the table, and remove affected leaves promptly. Choose rust-resistant varieties when you buy seed.
Seedlings cut at the base
A seedling found lying flat with its stem cut through at soil level is cutworm damage. Push a cardboard collar around each seedling at planting time, and check the soil around damaged plants for the caterpillar curled up just under the surface.
Plants stop flowering in summer
Snapdragons are cool-weather plants, and summer heat makes them stop flowering and go leggy. This is normal: grow them for spring, cut them back after the first flush for a second round, and sow again in late summer for autumn flowers.
Frequently asked questions
How long does it take to grow snapdragons?
From planting to maturity takes 80–90 days. Seed germination takes 7–14 days, and the total time depends on whether you start from seed, a nursery plant, or a bulb or cutting.
How far apart should I plant snapdragons?
Space snapdragons 6–12 inches apart. That spacing gives each plant room for air movement, which keeps disease down, and room to reach its full size without crowding its neighbours.
What soil pH do snapdragons need?
Snapdragons prefer a soil pH of 6.0–7.0. Test your soil before amending it — most garden soils are close enough, and guessing with lime or sulphur can do more harm than good.
Are snapdragons annuals or perennials?
They are usually grown as annuals, but they are short-lived perennials in mild, frost-free zones, where they can live for a few years. In most gardens they are sown fresh each year, and they self-seed freely.
When should I sow snapdragons?
Sow indoors in late winter for spring flowers, or in autumn in mild zones for winter and spring blooms. Seeds germinate in 7–14 days, and plants reach maturity in 80–90 days.