In western North America, Burrowing Owls are most normally found in arid grasslands or desert-like conditions. (This photo was taken in Lake Havasu, AZ in February of 2020.) The wet, wooded environment of Western Washington is generally not considered a Burrowing Owl's preferred habitat.
1) Learn and leave established native flora undisturbed.2) Remove invasive species and then wait to see if native plants begin to grow without assistance. (If native plants start on their own, then these plants or trees are likely the most appropriate flora for the habitat.)3) Scatter seeds from nearby native plants in a similar habitat.4) If you feel you must add a new plant then select a native plant while considering how the plant fits with the specific habitat and understanding the plant's logical place in the normal succession of native plants.
My intention in my weekly post is to include at least one photo each week and visually challenge us to know the difference between native and non-native lifeforms.
Also, Jane Lundin has created a small package, with a lot of critical information that looks quite handy, and light, for backpacking in the mountains in Springtime. It is titled, Mountain Wildflowers of Washington.)