Frozen Iii: The Cold Snap Story Continues….

By Jane Rozum, CSU Extension Horticulture Agent, Douglas County

 

When I last wrote a blog article about last November’s Cold Snap on December 23, 2014 here, I talked about the needle damage on evergreens along Colorado’s Front Range. I related the story of our mild October weather and how temperatures went from the 50° F range to well below zero (-15°F in some areas) in 24 hours or less. Conifers hadn’t acclimated to our cold winter temperatures and many needles froze and turned brown. Some trees had significant needle browning; many young trees were lost. Colorado State Specialist Tamla Blunt authored a bulletin which described the reasons why evergreens received damage.

Since December, Extension professionals in the Front Range and Eastern Plains have been fielding calls from homeowners worried about their evergreens. Some questions have touched upon whether deciduous trees and shrubs were affected by the Cold Snap. Now that spring is here, we are seeing what appears to be Cold Snap damage to these landscape plants.

Thanks to CSU’s PestServe list, green industry and Extension professionals as well as Colorado Master Gardeners and citizens have been chronicling the damage which has been observed on deciduous landscape plants. So far, the list of plants which demonstrate cold damage dieback, sometimes to the ground, is rather lengthy:

 

Trees:

Fruit trees such as Apple, Pear, Cherry

Pyrus calleryana- Callery Pear – less blooms

Prunus cerisifera ‘Newport’

Plums

Salix sp., especially Globe Willow

 

Conifers: Juniper, Arborvitae (in addition to previously observed damage to pines, spruces, etc)

Shrubs:

Burning Bush (Euonymus alatus cultivars)

Cotoneaster species

Rose – cane dieback to ground

Euonymus fortunei cultivars

Boxwood (Buxus sp.), burned or damaged

Privet (Ligustrum)

Spirea

Weigela

Buckthorn (Rhamnus sp.)

Holly

Barberry (Berberis cultivars)

Daphne (Carol Mackie cultivar)

Hibiscus syriacus

Silver Lace Vine Polygonum aubertii  

As more trees and shrubs leaf out, we may continue to see damage from landscape plants that were affected by the November Cold Snap. What have you noticed in your landscape? Please feel free to comment on whether you have seen significant dieback on woody and other landscape plants this year.

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