When to Plant Snapdragon in Colorado

Snapdragons (Antirrhinum majus) are classic cool-season annuals whose upright spikes of dragon-lipped flowers are among spring's most dramatic displays. Tolerating light frosts, they bloom from early spring until summer heat shuts them down — then often revive in fall. In zones 9-11 they are grown as fall-planted winter annuals and may re-seed to naturalize.

Colorado spans USDA hardiness zones 4b, 5a, 5b, 6a, 6b, 7a (with planting data available), so planting dates vary by your location within the state. Click your zone below for the most accurate dates.

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Click your county for exact Snapdragon planting dates based on your local frost dates.

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Snapdragon Planting Calendar for Colorado

▸ Zone 4b ~155 day growing season · Full guide →

Last frost: May 1 · First frost: October 3 · 155 day season

Activity	When	Date Range
Start Indoors	February 20	Feb 20 – Mar 6
Transplant Outdoors	May 1	May 1 – May 15
Bloom	July 10	Jul 10 – Sep 4

▸ Zone 5a ~166 day growing season · Full guide →

Last frost: April 25 · First frost: October 8 · 166 day season

Activity	When	Date Range
Start Indoors	February 14	Feb 14 – Feb 28
Transplant Outdoors	April 25	Apr 25 – May 9
Direct Sow	April 11	Apr 11 – May 2
Bloom	July 4	Jul 4 – Sep 5

▸ Zone 5b ~178 day growing season · Full guide →

Last frost: April 18 · First frost: October 13 · 178 day season

Activity	When	Date Range
Start Indoors	February 7	Feb 7 – Feb 21
Transplant Outdoors	April 18	Apr 18 – May 2
Direct Sow	April 4	Apr 4 – Apr 25
Bloom	June 27	Jun 27 – Sep 5

▸ Zone 6a ~193 day growing season · Full guide →

Last frost: April 10 · First frost: October 20 · 193 day season

Activity	When	Date Range
Start Indoors	January 30	Jan 30 – Feb 13
Transplant Outdoors	April 10	Apr 10 – Apr 24
Direct Sow	March 20	Mar 20 – Apr 10
Bloom	June 19	Jun 19 – Aug 28

▸ Zone 6b ~205 day growing season · Full guide →

Last frost: April 3 · First frost: October 25 · 205 day season

Activity	When	Date Range
Start Indoors	January 23	Jan 23 – Feb 6
Transplant Outdoors	April 3	Apr 3 – Apr 17
Direct Sow	March 13	Mar 13 – Apr 3
Bloom	June 12	Jun 12 – Aug 28

▸ Zone 7a ~221 day growing season · Full guide →

Last frost: March 25 · First frost: November 1 · 221 day season

Activity	When	Date Range
Start Indoors	January 14	Jan 14 – Jan 28
Transplant Outdoors	March 25	Mar 25 – Apr 8
Direct Sow	February 25	Feb 25 – Mar 18
Bloom	June 3	Jun 3 – Aug 26
Fall Sowing	September 6	Sep 6 – Sep 20

Growing Tips for Colorado

Start indoors 10-12 weeks before last frost; seeds need light to germinate — press into moist medium and do not cover. Transplant after hardening off, even if light frosts remain. Pinch seedlings once to encourage branching. Deadhead to prolong blooming. In zones 8-11, sow in fall for a winter-to-spring show. Tall varieties (24-36") make excellent cut flowers.

Snapdragon in Other States

Frequently Asked Questions

When should I plant Snapdragon in Colorado?

Planting dates for Snapdragon in Colorado depend on your USDA zone. Colorado spans zones 4b, 5a, 5b, 6a, 6b, 7a. Check the planting calendar above for your specific zone's frost dates and planting windows.

What zone is Colorado for planting?

Colorado contains USDA hardiness zones 4b, 5a, 5b, 6a, 6b, 7a. Your specific zone depends on your location within the state — northern and higher-elevation areas are in colder zones, while southern and coastal areas are warmer.

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