May 6, 2013
Shrubs for Winter Interest in Zone 5
Spokane has such long winters that evergreens and other interesting winter elements are an especially important part of good landscape design. I started my backyard design by making sure there were evergreen elements (evergreen shrubs or perennials, boulders, etc.) in every area of the garden. My front yard has evolved to this point and it works well. Above is one of the three 'Helsinki University' rhododendrons that I planted in the east backyard garden area. Rhodies and other acid-loving broad leaved evergreens are no brainers in areas with acidic soil (like Seattle or much of the Eastern US), but they require extra care in Spokane's more alkaline soil. So I'm only doing three of them.
Here is a photo of the new leaves growing on my rhodies. I incorporated a lot of acidic peat moss into the planting holes and will spread acidic fertilizer around them each year. On the east side of the home the rhodies are sheltered from wind and intense afternoon sun, which should cut down on windburn and sunburn. I also made sure they are in areas that do not have drainage problems, since rhodies hate having soggy roots. 'Helsinki University' is hardy down to zone 4, so it shouldn't have a problem surviving our zone 5 winters. Hopefully I can nurture these babies into healthy shrubs that reach their full size of 4-6' tall by 3-4' wide.
The main evergreen structure in my backyard will come from three types of boxwoods. Above you can see 'Green Velvet' boxwoods (3-4' Tall & Wide) at the Spokane LDS temple - there are two rows of dwarf red-twigged dogwoods in front and the boxwoods are in the middle. I have planted eleven in my backyard. Obviously these roundy-moundy shrubs just blend into the landscape during the summer, but in the winter they will keep my garden beds from looking completely bare. Six groups of three 'Green Mountain' boxwoods (5'T x 3'W) are spaced along the fence line of my backyard. These oval shrubs will cut down on glare from the white fence in winter and will provide a nice backdrop in summer for flowers and interesting foliage on other plants.
The final type of boxwood in my backyard is the columnar 'Green Tower' (9'T x 2'W - above). Some people use these to make a hedge, but I've placed them singly and in pairs in spots where their columnar form will make a statement all year. There are two of these in my front yard, which helps to link the front and back yards together. I also have four 'Wee Willie' boxwoods (2'T & 2'W) in the west front yard. These further connect the different areas.
Another evergreen shrub that links my front and back yards is 'Otto Luyken' laurel (3-4'T x 4-6'W). The photo above is from the LDS temple in Richland, WA. I have five of these in different areas of the front yard and five more planted around the backyard. They tolerate sun or mostly shady conditions and will blend into the landscape in summer but provide a different texture and darker leaf color than all the boxwoods in winter. It's very convenient that they tolerate different lighting conditions, as they'll grow fine in the sun while my trees are small but continue to do well as the trees mature and cast more shade. Hellebores are an evergreen perennial that I planned to use heavily around the backyard for winter interest, but they do not tolerate sun so I'll have to wait a few years to plant them in many places.
Not all shrubs with winter interest are evergreen. I was very excited to find space for a contorted filbert (Corylus avellana 'Contorta', 8'T x 8'W), also known as Harry Lauder's walking stick. This shrub forms corkscrew limbs that are hidden by its leaves in the summer but are revealed in winter.
My shrub is very small, but here is a mature version at the Northwest Garden Nursery in Oregon. Beautiful, especially with the moss covering the lower branches. By including all of these shrubs plus boulders and eventually the hellebores, my backyard should retain some structure and interest all year.