So you have root rot on your property and the resulting pocket of dead and dying trees. Management guidelines to mitigate this forest health problem may include cutting all trees within the diseased center, as well as all uninfected trees within 50 feet. Then you might regenerate the site with ponderosa pine, western larch and/or lodgepole pine to replace the more-susceptible Douglas fir and true fir.
But instead of replanting, why not leave the pocket clear of trees?
Small openings in forests are known to attract deer, turkey, black bear and other wildlife. Another type of “wildlife” that you may attract to a forested opening are beneficial insects such as pollinators. Pollinators are important for plant reproduction and therefore, ecosystem health. Unfortunately, pollinators are threatened worldwide by habitat loss and fragmentation, as well as a myriad of other problems. Leaving your root rot pocket clear of trees will not only help eradicate root rot, but it may aid the conservation of pollinator species such as bumblebees, hummingbirds, moths and everyone’s favorite; butterflies.
Washington is home to many beautiful species of butterfly. Common butterfly species you may attract include the painted lady (Vanessa cardui) and the Western pine elfin (Callophyrs eryphon). Less common but also beautiful are the blues (Family: Lycaenidae). Potential blues you may attract in the various regions of eastern Washington include the arrowhead blue (Glaucopsyche piasus), Boisduval’s blue (Plebejus icarioides), lupine blue (Plebejus lupini), melissa blue (Plebejus melissa), silvery blue (Glaucopsyche lygdamus), Northern blue (Plebejus idas), greenish blue (Plebejus saepiolus) and the spring azures (Celastrina lucia and C. echo).
To attract a diversity of species, consider planting a variety of the flowers and shrubs needed for all the life stages of the butterfly (egg, larva, pupa, and adult) within your root rot pocket. Incorporating a mixture of species that provide continual blooms for nectar-feeding adults throughout the growing season would be most beneficial, including at least one species each for spring, summer, and fall. If you decide to include shrubs in your patch, they should be planted at the edge of the tree line to aid in tapering the vegetation.
There are many potential native plant species to consider. The Western pine elfin caterpillar feeds on the young needles of pines and the adults feed on flower nectar, while the painted lady prefers thistles. Generally, blues are attracted to lupine (Lupinus spp.), clovers (Trifolium spp.), and wild buckwheat (Eriogonum spp.) for both larval food and nectaring.
In addition to providing food, you could go the extra mile and include additional features necessary for butterfly survival. A bird bath filled with sand and wetted with water would provide a nice puddling area. A small salt lick may also be placed in the bird bath to provide mineral requirements. Rocks are great for basking in the sun, while snags, logs and brush piles provide overwintering sites.
Plot maintenance may be needed periodically. Weeds can be controlled mechanically (by hand) or with herbicides. Mowing should be avoided, as this could destroy eggs, caterpillars, and pupae located on the vegetation.
If you have livestock, keep in mind that some plant species are poisonous. For example, silky lupine (L. sericeus), velvet lupine (L. leucophyllus), and silvery lupine (L. argenteus) are known to cause birth defects in cattle.
For more information on butterflies found in your area, visit the Butterflies and Moths of North America website.
By Melissa J. Fischer, Forest Health Specialist, Northeast Region, Washington State Department of Natural Resources, firstname.lastname@example.org