What temperature range can cause injury to woody ornamentals grown in containers?

Woody ornamentals grown in containers are particularly vulnerable to cold temperatures due to their exposed root systems, which are not insulated by soil as they would be when planted in the ground. A temperature range between 18 to 24°F can lead to damage, as it may cause the roots to freeze or suffer from frost injury. Container-grown plants often have limited access to thermal protection, so temperatures within this range can severely impact their health, leading to symptoms such as dieback, leaf drop, or even plant death.

This understanding of woody ornamentals' susceptibility to cold helps in planning protective measures during colder months, such as bringing containers inside, using insulation, or wrapping the containers with materials to mitigate the effects of low temperatures. Knowing the critical temperature thresholds is essential for effective wintering strategies in horticulture.