what would be some of the hardiest evergreen shrubs to consider for a hedge...
Thank you for contacting us. As you probably already know, there aren't many species that can withstand the cold and wind of NE Washington. To answer your question, I researched shrubs recommended for your area, and compared them to lists of plants recommended for the colder areas of Minnesota. This gave me a short list of shrubs and trees depending on how tall you want the hedge to be.
All of the recommended species are conifers; please remember that in any area where they are exposed to wind, these plants will need extra water in the fall, so they can be fully hydrated for the winter.
Rocky Mountain juniper, Juniperus scopulorum, is an upright growing shrub with a bluish color, that grows about 12-15' tall. It needs full sun in order to thrive.
Eastern red cedar, Juniperus virginiana, is very similar, but green in color. In its native range it can grow to 30' tall, but I've not seen it get that tall in eastern Washington. The tallest ones I've seen are about 20-25' tall after 30 years or more.
Some websites will recommend Northern white cedar, which is Arborvitae, also known as deer candy in this area. I would not recommend this plant for your hedge.
Austrian pine, Pinus nigra, can grow to 30' in our area, and if that is not too tall, then it might be a good choice for your hedge. It has a more dense canopy than our native pines, and is often used as a windbreak, even in really dry areas of the state. These pines may not last as long as some plants, maybe only 30-40 years, as opposed to 100+ years for Ponderosa pines.
These three choices are probably the toughest plants to try for your hedge, but just in case you want to do some more research, we have a publication called "Trees Against the Wind" which can be found at this link:
http://cru.cahe.wsu.edu/CEPublications/pnw0005/pnw0005.pdf This will give you more information about the various species used for hedging, and where they are hardy.
Thank you for contacting us, and best of luck with your hedge!