The biggest show at Crater Lake National Park is its namesake, Crater Lake, which is, by some measurements, the deepest in the Western Hemisphere. However, the thriving flora of the park is equally impressive and has been relatively unencumbered by invasive species throughout its history.
Crater Lake National Park features 50,000 acres of old-growth forest. The top types include pines, firs and hemlocks. Recently, the whitebark pines have been besieged by blister rust, which has been killing them.
Sphagnum Bog in the northwest part of the park is a breeding ground for all kinds of moss. Beyond that, in the deeps of Crater Lake are massive mosses that are more than 4,000 years old.
The botrichium pumicola is the rarest fern at Crater Lake and grows only on the highest pumice slopes. Besides this, there are more than 20 fern species in the park.
There are 35 species of fruit-bearing bushes throughout Crater Lake, with the most common being the nonedible red berry-bearing Crater Lake currant.
Wildflower gardens dot the park, filled with a variety of local plants. The park holds many varieties of sunflowers, irises, bell flowers, morning glories, geraniums, primroses, buttercups and roses.