Freeze Protection for Oleanders

Selection

• Selection helps prevent freeze damage before it occurs. Oleanders exhibit hardiness to USDA Zone 8b, or areas with average annual minimum temperatures of 15 to 20 degrees Fahrenheit. Growing standard oleander in colder zones guarantees cold damage. According to a Clemson University publication, oleander express difficulty even in colder regions of South Carolina. Choosing cold hardy oleander varieties helps prevent freeze damage in cold regions. The calypso oleander cultivar (Nerium oleander ‘Calypso’), for instance, expresses greater cold hardiness than standard specimens.

Placement

• Planting oleanders in certain places may help prevent freeze damage. Areas with western and southern exposure usually receive the most natural heat. Surfaces such as walls, rocks, benches and patios reflect the heat of the sun, keeping plants warm during the winter. Oleanders prefer open sun exposure, which provides optimal direct heat during the winter, though may leave plants susceptible to freeze damage. Planting oleander in partial shade beneath trees leads to colder temperatures though protects against radiation freeze, which occurs when temperatures drop drastically and heat quickly radiates away from objects such as plants.

Retaining Heat

• Retaining heat means trapping the heat around a plant in cold times of year to prevent damage from frost or freezing. Placing a cloth, blanket or paper covering over a plant helps retain warm air rising from the soil. Do not use plastic, which may prevent the circulation of oxygen and cause other damage. Never tightly wrap a cloth, as it prevents warm air from rising to the top of the plant. Use a light cloth to avoid damaging your oleander.

Adding Heat

• Adding heat to oleanders during cold periods helps prevent freeze and frost damage, particularly when used in conjunction with covered plants. Placing a 100-watt light bulb in a safe outdoor fixture below the foliage line of your oleander provides heat that rises within the plant’s cover, keeping the specimen warm. Keep the light fixture at a safe distance from a specimen to avoid burning the plant. Fans also help prevent freeze damage by encouraging air circulation, which increases the movement of war air around a plant.

Additional Information

• Watering plants before a freeze helps prevent freeze damage. Moist soil absorbs more heat than dry soil and gives heat off more quickly. Moist soil around your oleander can absorb a great deal of heat during the day and give it off rapidly at night to keep the plant warm during the coldest times. Maintaining optimal plant health through fertilizing, soil conditions and watering helps prevent damage by generally fortifying your oleander. Moving oleanders planted in containers into the house during the winter constitutes the easiest method to protect such plants from freeze damage. If your oleander experiences cold damage, prune all damaged areas to allow for new growth. Only prune plants in the spring, after the last frost, to avoid exacerbating the damage.