Common Name: Frost
Type: Plant Damage
Major Identifying Features: Cold temperatures below freezing (32°F), or temperatures at 32°F or higher and plant tissues drop to 32°F
Life Cycle: Not considered as a pest
Pest Rating: Not considered as a pest
Management Rating: Difficult
Host/Season/Outbreak Information: Autumn and spring, winter, cool clear nights, when temperatures drop quickly
Damage Information: Curled, dead, or brown buds and flower shoots, foliage appears scorched due to dehydration. Bark and wood can crack and split, entire plants may be killed (depending on toleration). Plant roots are more susceptible to cold damage in pots and planters. Damage resembles anthracnose, gas or mechanical injury, phytotoxicity, or water deficit.
Management Options: Choose species well adapted to the climate and seasonal temperatures for the location, consult the California Master Gardener Handbook and Sunset Western Garden Book, control weeds, remove mulch on soil during winter months, irrigate 3 days before freezing weather, cover sensitive plants over night with cloth, do not prune freeze-damaged plants until you are certain that plant tissue is dead, remove limbs and trunks that might become a hazard
Dreistadt, Steve H., and Jack Kelly Clark. Pests of Landscape Trees and Shrubs: An Integrated Pest Management Guide. Oakland, CA: U of California, Agriculture and Natural Resources, 2016. Print.