Spring has finally arrived, but many of us are still reeling from the harsh winter. And the especially large number of wildlife deaths recently because of toxic yew (Taxus) has Treasure Valley residents searching for an alternative to the popular landscaping plant.
For most local homeowners, yew is just a plant that showed up in their yards, perhaps planted by a previous owner or a hired landscaper to create a certain look.
The kind of yew used in many landscapes is not native to Idaho, and is toxic to humans and pets as well as to the large numbers of wintering wildlife who were searching throughout the Valley for food sources that weren’t buried under snow.
Now that the ground has thawed, consider getting rid of your yews and planting some of these alternatives instead. And while you’re at it, we have a couple more recommendations for making your yard more regionally appropriate and lower maintenance.
What was the yew’s role in your yard?
First, reflect on what purpose yew is serving in your yard. Is it creating a hedge? Do you need to be able to prune it? Is it in a shady area? Do you enjoy the fact that it stays evergreen?
Then, consider the following options:
▪ If you need something you can prune, Arbovitae (Thuja) is a popular, hardy option, able to withstand years of pruning. Also worth a look is Oregon grape (Mahonia aquifolium), a regionally native plant that can be pruned somewhat formally.
▪ For an evergreen replacement, consider Austrian pine (Pinus nigra), particularly the cultivar ‘Arnold Sentinel,’ which has a compact, columnar form. Curleaf mountain mahogany (Cercocarpus ledifolius) is a lovely, less formal option that is also native to this region. ‘Skyrocket’ Western juniper has a tidy columnar shape that provides plenty of screening.
▪ If you need to replace a yew in a shady area of the yard, the following are shade tolerant and all regionally appropriate: Oregon boxwood (Paxistima mysinites), Red Osier dogwood (Cornus stoloifera), Oregon grape (Mahonia aquifolium), and Ninebark (Physocarpus).
Some other plants you may want to reconsider
And since you have your garden gloves on ...
Have you noticed that everyone has Russian sage (Perovskia atriplicifolia) in their yard? Russian sage is a fine plant: perennial, drought-tolerant, airy, profusely flowering, but vastly over-planted in the Treasure Valley. Additionally, it has a high oil content, making it flammable and thus not an ideal choice for firewise areas.
Brett van Papeghem with the Idaho Firewise program, recommends substituting Rocky Mountain penstemon, which is firewise and drought tolerant. Other penstemons are equally good substitutes, as well as the plethora of blue salvias you can find in any nursery.
Catmint (Nepeta) ‘Walker's Low’ is a profuse bloomer that is popular with pollinators, and this selection will not re-seed.
If you need a break from the blues and purples, try Appleblossom grass (Gaura lindhimeri), available in white or pink, or Yarrow (Achillea millefolium), available in a variety of cultivars with flowers of white, yellow, pink and terra cotta.
For a bold red with a loose habit similar to Russian sage, check out Red Mexican sage (Salvia darcyi) or Bridges penstemon (Penstemon rostriflorus). All these suggestions are drought tolerant, long bloomers that are planted far less frequently than Russian sage.
Say no to Rhodendrons
Another plant that Treasure Valley gardeners should reconsider: Rhododendrons. Yes, we all love their gorgeous blooms, but they are also completely unsuited to growing in the Treasure Valley, due to their love of moist, acidic soil and moderate temperatures.
This area is, in fact, the exact opposite of what Rhododendrons want in an environment. According to the American Rhododendron Society: “Regions suitable for growing rhododendrons and azaleas are those that have naturally acidic soils, adequate water availability, moderate humidity and winds and lack of temperature extremes.” So if you love Rhodies, go ahead and try them, but if you want something easier, we offer the following options:
Hydrangeas have spectacular blooms and come in a multitude of cultivars. Lilacs (Syringa is the Latin name, not to be confused with the local name used for the Idaho state flower) are also available in a number of colors and flower forms. More information on lilacs is available here: idahobotanicalgarden.org/whats-blooming-532016.
Viburnums are another versatile choice, with more than 150 species and numerous cultivated varieties. Many viburnums feature showy flowers, colorful berries and fall foliage.
Apache Plume (Fallugia paradoxa) and Fernbush (Chamaebatiaria millefolium) are two native options that produce an explosion of white flowers throughout the season and attract native pollinators.
For more inspiration and additional ideas for regionally appropriate plants, visit the Idaho Botanical Garden at 2355 Old Penitentiary Road in East Boise. The garden is open daily. Learn more at IdahoBotanicalGarden.org.
The professionals on the Horticulture staff at the Idaho Botanical Garden are responsible for planting and maintaining the 15 acres of specialty gardens, each with a unique focus. IBG’s Horticulture staff has many years of professional experience and education, and the team includes graduates of Boise State University, the University of Idaho, Oregon State University, the College of Western Idaho and Texas A&M University.