Knowledgebase
Cedar apple rust and arborvitae #731012
Asked October 16, 2020, 8:29 PM EDT
Livingston County Michigan
Expert Response
Hello,
Plants now called arborvitae, Thuja occidentalis and Thuja plicata, were once commonly called types of cedars, though they are not true cedars. The Thuja genus plants do not host rust diseases. The issue with arborvitae is they are a favorite food of deer, and they have some pests and diseases to monitor, though these do not affect apples.
http://hort.uconn.edu/detail.php?pid=501
http://hort.uconn.edu/detail.php?pid=500
Another consideration is mature size- depending on how they are sited, you don’t want your screen to shade your apple trees when they become tall.
There are other evergreens to use in hedges, and planting a variety is recommended so that in future, if a disease or pest wipes out a species, the whole hedge isn’t lost. Black Hills spruce and Canadian hemlock are examples of plants for wind screens. Again, mature size is a consideration as are the other growing requirements such as soil pH and moisture.
Rust spores can travel on wind several hundred yards, so you still need to monitor your apple trees. Rust diseases are hosted by Juniperus genus, such as eastern red cedar, Rocky Mountain juniper, and Chinese junipers. Here is a detailed discussion of the four rust diseases:
More References-https://www.agriculture.purdue.edu/agcomm/newscolumns/archives/ITG/2005/May/050505ITG.htm
https://www.canr.msu.edu/hrt/uploads/535/78626/cedars.pdf
https://extension.psu.edu/using-trees-and-shrubs-for-privacy-and-wind-screening