I think we’d all agree, the past winter season was a long and difficult one. Even now, in the third week of May, temperatures are struggling to reach 70°. And the three overriding questions remain…will summer ever arrive? How do I explain to my boss, club members, clients, etc. why so many plants look dead after the winter of 2013-14? And perhaps most importantly, why was this past winter so tough on landscape plants?
Consider these events important events:
- As we entered late fall and early winter, soil conditions were very dry.
- As a result, many landscape plants entered winter under stress or in a weakened condition.
- Severe low temperatures (before measureable snowfall) caused the soil to freeze to impressive depths. This could have resulted in root death to sensitive or stressed plants.
- When snowfall eventually arrived, it blanketed the ground without interruption, persisting until early spring in some locations and ensuring frozen soil until late March/early April.
- Strong winds seemed to be an everyday occurrence. When coupled with high light intensity and frozen soil conditions, the damage to evergreens became a foregone conclusion.
- Finally, low temperatures, the likes we haven’t seen for many years, helped create the perfect storm.
Mitigating Winter InjuryWinter injury may not be immediately apparent when plants resume growth in the spring. Some plants may actually leaf out and appear quite normal for a time, only to decline and die later during stressful summer conditions. To minimize unsightliness and promote plant health, dead wood should be pruned out as it becomes apparent.
Department of Horticulture
Iowa State University
Below you will fine a few pictures taken by Dr. Iles around Ames.