Winter Protection for Azaleas and Rhododendrons: Anti-Desiccants Not Oil

Correct Winter Injury Prevention

An Ohio (zone 4) gardener had azalea/rhododendron winter kill last year, asks about dormant oil vs. Volck oil spray for winter protection.

Oil Doesn't Prevent Winter Desiccation

Ed Gulliksen clarifies: horticultural oils control pests, not winter drying. Use anti-desiccants (Nu-Film, Vapor Gard) that seal leaf pores against moisture loss.

Application Schedule

• First application – Late October to early November
• Second application – February

Anti-desiccants, not oils, prevent winter burn on broadleaf evergreens.