Exploring the Impressive Cold Tolerance of Ivy Plants

With its lush green foliage and vining growth habit, ivy makes a beautiful addition to gardens and landscapes. But how cold tolerant is this popular plant? Ivy possesses an admirable ability to withstand frigid winter temperatures. Understanding the cold hardiness of ivy enables proper planting and protection.

The Minimum Temperature Ivy Can Tolerate

• Most English ivy cultivars tolerate temperatures down to -10°F (-23°C) when fully hardened off.
• In some cases, mature English ivy can briefly survive dips to -20°F (-29°C).
• Boston ivy withstands temperatures as low as -30°F (-34°C).
• Needlepoint ivy survives temperatures down to -15°F (-26°C).

These impressively low temperatures demonstrate ivy’s excellent cold acclimation However, extended exposure to temperatures below its minimum can cause damage

Factors That Influence Ivy’s Cold Tolerance

Ivy’s ability to survive cold is influenced by several factors

• Species and cultivar – Some are more cold hardy than others.
• Age – Mature ivy tolerates colder temperatures than young plants.
• Health – Cold tolerance diminishes if plants are stressed.
• Exposure – Sheltered ivy withstands colder temps than exposed plants.
• Soil warmth – Insulated soil protects roots from freeze damage.
• Hardening off – Gradual exposure to cold increases tolerance.

Protecting Ivy from Winter Temperatures

While ivy has natural cold resistance, some protections can help it survive frigid conditions

• Mulch insulates roots and soil from temperature swings.
• Burlap wraps or blankets buffer leaves from harsh winds.
• Microclimates next to buildings or walls provide shelter.
• Bringing potted ivy indoors prevents freeze damage.

Avoid fertilizing late in the season so plants harden off properly. Continue watering during winter to prevent desiccation damage.

Signs of Cold Injury in Ivy

If temperatures drop below ivy’s tolerance, symptoms of damage arise:

• Leaves turn black or appear water soaked.
• Foliage develops brown spots or margins.
• Wilted, curled, or drooping leaves.
• Dieback of stems and leaf loss.
• Discolored and damaged roots.

Severe injury can kill ivy plants. Milder symptoms impact appearance but don’t threaten the plant’s survival.

The Best Cold Hardy Ivy Varieties

• English ivy – Tolerates temperatures as low as -10°F (-23°C).
• Boston ivy – Withstands temperatures down to -30°F (-34°C).
• Algerian ivy – Survives temperatures as low as -10°F (-12°C).
• Needlepoint ivy – Hardy in temperatures down to -15°F (-26°C).

Select an appropriate cold-tolerant species or cultivar for your climate. Reference USDA Hardiness Zones when choosing plants.

Caring for Outdoor Ivy in Winter

To help your ivy thrive through winter:

• Water during warm spells to prevent desiccation.
• Apply winter mulch after the ground freezes to insulate soil.
• Wrap or cover ivy to shield from drying winds.
• Delay any pruning until spring to avoid cold damage.
• Monitor for signs of freezing injury.

Adjust care as needed to prevent or reduce cold damage.

Transitioning Indoor Ivy for Winter

As temperatures drop:

• Gradually expose indoor ivy to cooler temps to harden off.
• Move indoor plants away from drafty windows.
• Maintain indoor temperatures above 60°F for tropical varieites.
• Water sparingly since growth slows.
• Watch for leaf drop as ivy enters dormancy.

With attention to its needs, indoor ivy will sail through the cool months.