Snapdragons are cool-season flowers. Illinois Extension calls them very cold tolerant and good for early spring and fall planting. In most gardens, start seed indoors about 8 to 10 weeks before your last frost (GardenPal estimate) and plant hardened seedlings out from about 2 weeks before the last frost. For a fall show, Illinois Extension says plants set out in mid to late summer bloom until a hard frost. In Florida, UF/IFAS says to plant from October through February.
Snapdragon (Antirrhinum majus) is a short-lived tender perennial usually grown as an annual (NC State). Sizes run from about 6 inches to 3 feet (UF/IFAS, Illinois Extension), from trailing types for containers to tall spikes for cutting. The plants do best in cool weather; NC State says they languish in summer heat, so the timing below is about catching spring and fall.
Spring dates by last frost
Snapdragons are slow from seed. University of Missouri Extension gives them one of the longest crop times in its flower table, 15 to 16 weeks, and an early-March indoor sowing date for mid-Missouri. GardenPal's estimate for seedlings big enough to plant out is 8 to 10 weeks of growing indoors. Because the plants are very cold tolerant (Illinois Extension), hardened seedlings can go out a little before the average last frost.
| Average last spring frost | Start seed indoors (GardenPal estimate) | Plant hardened seedlings out (GardenPal estimate) |
|---|---|---|
| Mar 1 | Dec 21 – Jan 4 | Feb 15 – Mar 1 |
| Mar 15 | Jan 4 – Jan 18 | Mar 1 – Mar 15 |
| Apr 1 | Jan 21 – Feb 4 | Mar 18 – Apr 1 |
| Apr 15 | Feb 4 – Feb 18 | Apr 1 – Apr 15 |
| May 1 | Feb 20 – Mar 6 | Apr 17 – May 1 |
| May 15 | Mar 6 – Mar 20 | May 1 – May 15 |
| Jun 1 | Mar 23 – Apr 6 | May 18 – Jun 1 |
Fall planting
Illinois Extension says snapdragons are excellent planted in mid to late summer and keep going until a very hard frost. GardenPal's estimate is to set transplants out about 8 to 10 weeks before your first fall frost, which gives them time to bloom in the cool weeks of fall:
| Average first fall frost | Set out fall transplants (GardenPal estimate) |
|---|---|
| Sep 15 | Jul 7 – Jul 21 |
| Oct 1 | Jul 23 – Aug 6 |
| Oct 15 | Aug 6 – Aug 20 |
| Nov 1 | Aug 23 – Sep 6 |
| Nov 15 | Sep 6 – Sep 20 |
Florida and mild-winter areas
Where winters are mild, snapdragons are a winter flower. UF/IFAS says October and November are the time to plant them in Florida, and that you can keep planting through February for steady winter color. In North Florida it suggests protecting plants on the coldest nights. Pansies are another winter flower there; see when to plant pansies.
Site, soil and care
| Step | What extension sources say |
|---|---|
| Sun | Full sun (UF/IFAS); full sun to light shade (Illinois Extension); full to part sun (NC State) |
| Soil | Moist, rich, well-drained soil (NC State); well-drained and tending toward alkaline (Illinois Extension); amended with organic matter (UF/IFAS) |
| Water | Avoid overhead watering (NC State) |
| Support | Tall cultivars may need staking (Illinois Extension, NC State) |
| Deadheading | Remove spent flower spikes to promote rebloom (Illinois Extension) |
Diseases to watch
NC State lists significant susceptibility to rust, plus mold, fungal leaf spots, downy mildew, wilt and root rots. Watering at the base, good spacing and well-drained soil all help. NC State also says the plants languish in summer heat, another reason to grow them for spring and fall.
Snapdragons in the vegetable garden
Illinois Extension notes that snapdragons attract butterflies, and they flower at the cool ends of the season when warm-season flowers like zinnias and marigolds are not yet blooming or are finished. Pair them along a bed edge with marigolds and zinnias for flowers from spring to frost, and see flowers that attract beneficial insects for more ideas.
Frequently asked questions
When should I plant snapdragons?
In early spring and again in mid to late summer for fall (Illinois Extension). GardenPal estimates setting spring seedlings out from about 2 weeks before your last frost.
When should I start snapdragon seeds indoors?
About 8 to 10 weeks before your last frost (GardenPal estimate). University of Missouri Extension lists early March for mid-Missouri and a long 15-to-16-week crop time.
Do snapdragon seeds need light to germinate?
Yes. University of Missouri Extension says they need light, so don't bury them. Germination takes about 7 to 12 days.
Can snapdragons survive frost?
Illinois Extension calls them very cold tolerant; plants set out in summer keep blooming until a very hard frost.
When do you plant snapdragons in Florida?
October and November, and you can keep planting through February (UF/IFAS).
Why do my snapdragons stop blooming in summer?
NC State says they languish in summer heat. Remove spent spikes (Illinois Extension) and expect a second flush when it cools.
Are snapdragons annuals or perennials?
A short-lived tender perennial usually grown as an annual (NC State).
Check which vegetables you're planting near your flower border, and spot any poor pairings before you plant.
Open itSources
- Virginia Cooperative Extension, "Companion Planting in Gardening" (SPES-620P)
- University of Maryland Extension, "Vegetable Succession and Companion Planting"
- Oregon State University Extension, "Companion Planting"
- Penn State Extension, "Herbs Make Good Plant Partners and Companions"
- University of Minnesota Extension, "Planting the vegetable garden"
- USDA Plant Hardiness Zone Map
- NOAA NCEI U.S. Climate Normals (frost/freeze data)
- NC State Extension Gardener Plant Toolbox, "Antirrhinum majus" (snapdragon)
- University of Illinois Extension, "Snapdragon" (flowers)
- UF/IFAS Gardening Solutions, "Snapdragon"
- University of Missouri Extension, "Starting Plants Indoors From Seed" (G6570)
Pairings are summarized in our own words from extension-service guidance. Research support for many companion effects is limited, so treat them as good habits, not guarantees.