Trilliums appear in the redwood forest during spring. The most common seems to be Trillium ovatum, which can be either white or purple / maroon.

Another trillium seen more rarely is Trillium chloropetallum / Trillium kurabayashii  ….  the places I’ve seen it were closer to water, like Redwood Creek trail at Redwood National Park,  and near Prairie Creek at Prairie Creek Redwoods State Park. It has upright reddish petals that almost twist upward. The leaves may be mottled.

Trillium ovatum seems to grow all over the the redwood parks. Near streams, hillsides, flat areas, etc..  It’s the wildflower shown below. Depending on location, soil temperature, etc., these can be found blooming in various locations during more than just one month. The image below was another year’s May 15th

Trillium ovatum