Evergreen Shrub Protection in Winter

This is winter in Nebraska.  Winter in Nebraska is by definition “variable”.  Long term residents seemingly are always telling newcomers that it’s colder this year or wetter this year or dryer this year or more up and down this year.  To sum, this is winter in Nebraska…variable.

 

As a result of variable conditions, especially the ones where cold drying winds impact our landscapes, vulnerable plants often show damage symptoms.  The group of plants that are the most vulnerable are the evergreen shrubs – boxwood, holly, Oregon hollygrape, euonymous, yews, dwarf alberta spruce and arborvitae.  These plants lose moisture through their leaves all winter long (they’re evergreen after all), as opposed to deciduous shrubs such as viburnums and dogwood.

IMG_8024

Generally, the result of a winter season of moisture loss is brown tissue, either on the edges of the leaves or entire leaves.

yew browning john mcdevitt

To prevent damage, three strategies are effective.

  1. Design the landscape such that these plants are not exposed to prolonged periods of drying winds. Instead, place them where a building or other plants interrupt it.
  2. In the beginning of winter, wrap a protective shield of burlap or plastic around them. This may look ugly, but then again, so do dead leaves in spring.
  3. Apply an anti-desiccant spray such as Wilt Pruf, Forever Green, Foliocote or Dwax…or the generic versions thereof. These products are essentially lightweight horticultural waxes that coat the leaves, keeping the moisture inside.  Generally, the effect of the application lasts for about 5-6 weeks, so making 3 applications over winter is appropriate.  One of the important label directions is to apply them on a day above freezing so that the liquid can dry on the leaves before nightfall.  Another is to thoroughly clean out the spray tank or bottle with warm water to prevent the supply line from turning a solid mass and rendering it useless.

IMG_4271

Shiny leaves of holly after an anti-desiccant application.

More information on this topic is available at: weather-ready.unl.edu/weather-ready-landscapes

John Fech
Horticulture Extension Educator at Nebraska Extension
John Fech is a horticulturist with the University of Nebraska-Lincoln and certified arborist with the International Society of Arboriculture. The author of 2 books and over 200 popular and trade journal articles, he focuses his time on teaching effective landscape maintenance techniques, water conservation, diagnosing turf and ornamental problems and encouraging effective bilingual communication in the green industry. He works extensively with the media to extend the message of landscape sustainability, making over 100 television and radio appearances each year.
John Fech on EmailJohn Fech on Twitter

Leave a Reply