How Cold Hardy are Snapdragons? A Complete Cold Tolerance Guide

With their tall elegant flower spikes in a rainbow of colors, snapdragons are a beloved cool weather annual in gardens across North America. While these fragrant beauties thrive in the mild temperatures of spring and fall, many gardeners wonder just how cold hardy snapdragons are when winter approaches.

The good news is that snapdragons are quite cold tolerant under the right conditions. By understanding their ideal climate preferences and properly hardening them off in fall, you can enjoy snapdragons in your garden through winter in many regions.

In this complete guide, we’ll cover everything you need to know about snapdragon cold hardiness including:

• The ideal climate for snapdragons
• How to prepare them for winter
• Their cold tolerance levels
• Overwintering techniques
• Which varieties are most hardy
• Troubleshooting cold damage

Arm yourself with knowledge about growing snapdragons in cold weather, and you’ll be rewarded with vivid flower color when other gardens have gone dormant.

What is the Ideal Climate for Snapdragons?

Native to the Mediterranean region snapdragons thrive in cool, temperate climates. They flourish in temperatures ranging

• Nighttime lows: 40-50°F
• Daytime highs: 60-75°F

These conditions are typically found in spring and fall in most of the U.S. While tolerant of some frost, snapdragons grow best when days are mild and nights are cool and avoid extreme heat or cold.

Their peak blooming time is during fall in Southern regions and early summer in the North. However, established plants can withstand much colder temperatures than their preferred range as long as they are properly hardened off before winter arrives.

How to Harden Off Snapdragons for Winter

The key to helping snapdragons survive freezing winter temperatures is gradually hardening them off as fall approaches. Here are some tips:

• Allow them to mature: Don’t plant seeds or tender transplants too late in fall when cold snaps are imminent. Give plants a chance to become well-established before winter.

• Provide supplemental water: Keep soils moist but not soggy during fall and winter to prevent drought stress. Add a layer of mulch to retain moisture.

• Withhold fertilizer: Fertilizing snapdragons during fall can encourage tender new growth that is more prone to cold damage.

• Leave developing seed pods: Allowing snapdragons to set seed before winter seems to boost their cold hardiness.

• Protect from wind: Cold winds can dessicate and damage plants. Use row covers, tunnels, or windbreaks to shield snapdragons during winter.

• Introduce cold gradually: If possible, move potted plants to unheated garages or porches before exposing them to freezing temps outside.

With these simple hardening techniques, your snapdragons will be primed to handle whatever winter throws at them!

How Cold Hardy are Snapdragons?

Once properly hardened off in fall, most snapdragons varieties can withstand freezing winter temperatures in the range of:

• Freezing point (32°F): Extended frosts down to freezing are generally fine for mature, established plants. New seedlings or transplants may suffer damage.

• Mid 20s°F: Snapdragons can tolerate short periods of temperatures dipping into the mid 20s (-5 to -2°C) when hardened off in fall. Prolonged deep freezes may cause some dieback.

• Teens°F: Brief exposures to temperatures in the teens (-7 to -9°C) may be survived by dormant snapdragons but typically cause significant dieback of shoots. Plants often regrow from roots in spring.

• Single digits°F: Very cold hardy varieties may live through brief cold snaps in the single digits but extreme freezes below 5°F (-15°C) usually kill most snapdragons, especially unprotected plants.

Keep in mind, exact cold tolerance depends on the individual variety, plant maturity, soil moisture, and exposure. But most garden snapdragons can remain alive with some protection into the mid to low 20°F range and the very toughest cultivars may persist as low as 5-10°F.

Best Techniques for Overwintering Snapdragons

If you live in an area prone to extreme winter freezes, there are some extra steps you can take to help your snapdragons survive the cold:

Cold frames: A simple cold frame constructed of straw bales, plastic sheeting, and old windows provides an insulated environment where snapdragons can overwinter in the garden, especially if given heat sources like lights or heating cables. Close the lid during freezing weather.

Row covers: Lightweight row cover fabric creates a protective microclimate that shields plants from wind and cold. Use hoops to prevent the fabric from resting on plants. Ventilate on sunny days.

Heavy mulching: A thick 4-6 inch layer of straw, shredded leaves, or other organic mulch helps insulate plant roots and crown. It’s best to wait until soil freezes before mulching to avoid smothering plants and encouraging rodents.

Potted snapdragons: Bringing containerized plants into unheated garages, porches, or greenhouses gives them extra protection from winter extremes while still allowing them to go dormant.

Which Snapdragons are Most Cold Hardy?

Snapdragons come in a range of colors, sizes, and growth habits. When selecting varieties for overwintering, look for these traits that boost cold tolerance:

• Large, mounded cultivars: The tallest varieties with the fullest foliage withstand winter better than dwarf types or those with sparse leaves.

• Old-fashioned open pollinated: Heirlooms like the Rocket series tend to be tougher than some modern F1 hybrids.

• Default flower colors: The classics – whites, pinks, reds, and purples – are generally more resilient than tropical shades like yellow, orange, peach, or bronze.

• Semi-evergreen foliage: Varieties that keep some leaves through winter bounce back quicker in spring than fully deciduous kinds.

Some exceptional cold-hardy snapdragon cultivars to try include: ‘Montego Blue’, ‘Montego Coral Rose’, ‘Rocket Lavender’, ‘Yellow Butterfly’, and ‘Maryland Pink’.

Troubleshooting Cold Damage

Even when hardened off properly, snapdragons may still exhibit some cold injury after exposure to extreme freezing temperatures such as:

• Wilted, water-soaked foliage
• Discolored, browned leaves
• Damaged shoots and buds
• Dieback of stems and upper branches

Don’t give up too soon on plants that look damaged! Snapdragons often regrow from their lower parts in spring. Prune away dead sections, provide frost protection, and wait to see if new growth emerges when temperatures warm up.

While individual plants may perish after bitter winters, leaving the roots intact allows snapdragons to self-sow and regrow as annuals the following year. With their impressive cold hardiness, a spot for snapdragons is a must in any fall garden!

Final Thoughts

One of the best aspects of snapdragons is their ability to thrive under cool conditions in both spring and fall. While not indefinitely hardy, most varieties can tolerate light frosts and short freezing spells, especially when properly hardened off before winter. Sheltering plants from harsh winds and extreme cold allows you to enjoy their elegant blooms season after season.

When provided slightly protected microclimates, plenty of mature foliage, moist soil, and varieties bred for hardiness, snapdragons can often endure freezing temperatures into the 20s°F and sometimes even brief stints below that in dormancy.

No flower heralds the start of fall like a tall row of vibrant snapdragons. With their outstanding cold fortitude, these beauties fill gardens with vibrant color well after summer annuals have faded away.