The Flower Bin

 Now’s the Time to Apply Dormant Oil 

 

Dormant spraying involves applying a preventative spray in late winter while fruit trees, deciduous trees and ornamental shrubs are still dormant. The “dormant” part of “dormant oil” describes the timing of the oil’s application, rather than the type of oil.  

 

Also called horticultural oils, dormant oils are highly refined oils that act to suffocate aphids, scale, mites and other insects which seek out shelter from the winter in the bark of trees and ornamental shrubs before they hatch.  Dormant oils dry quickly, have low persistence and don’t contribute to resistance buildup.  

   

 

Dormant oil product choices include concentrated ferti-lome Dormant Spray and ready-to-use ferti-lome Horticultural Oil Spray.

Both products contain Mineral Oil. Dormant oil can be applied with a tank sprayer or a hose end sprayer.  

 

Ideal conditions for dormant spraying would be on a day in early March when the temperature will be above 40°F, there’s little or no wind and no rain or snow in the forecast. Wind will carry the oil away from the tree or shrub you’re trying to protect. You’ll want to spray early in the morning so the plant will be dry by evening. Spray enough to cover the tree or shrub thoroughly.

Whenever you decide to spray, it needs to be before the bud starts to show color.  

 

Some trees such as blue spruce and blue juniper and ornamental shrubs are sensitive to dormant oils. Stop in and check with us to make sure you're selecting the right product for the trees and shrubs in your landscape.

Spraying now with dormant oil reduces the impact over-wintering aphids, scale and other insects can have later in spring and summer.