January: Pruning in the New Year

January is the time of year to start thinking about maintenance pruning for the trees and shrubs in your yard.

While there are exceptions, for many trees and shrubs, pruning during colder weather (when disease-causing organisms and insects are not active) can help minimize infections through pruning wounds.

The “January Thaw”

If you decide to prune, watch for the “January thaw,” when temperatures are warm enough that you will not freeze to death outside, but cold enough for plant pathogens and insects to have limited activity.

How To’s

For details on pruning, see:

Preventing Infections

As an added precaution to prevent infections, consider routine disinfestation (i.e., decontamination) of pruning tools as you prune.  In the best of all possible worlds, you should decontaminate between every pruning cut.  However, due to time constraints, this may not be feasible, but do consider disinfesting tools between every tree or shrub.

Dip them in alcohol

The best and probably easiest way to disinfest pruning tools is to dip them for at least 30 seconds in 70% alcohol (e.g., rubbing alcohol).

Use spray disinfectants

You can also use spray disinfectants that contain roughly 70% alcohol, in which case you spray your pruning tools until they drip and then allow them to air dry.

Dip them in a bleach solution

As an alternative to alcohol, you can dip tools for at least 30 seconds in a 10% bleach solution.


Bleach is corrosive to metal tools and will induce rusting when used repeatedly.

For More Information

For addition details on proper pruning, contact your county UW-Extension office or contact the PDDC at pddc@plantpath.wisc.edu.