The blooming period for bitterroot (lewisia reviva) is late May in our area. I have encountered it near Ashcroft (Elephant Hill and Black Canyon) and it is known to be found between Ashcroft and Spences Bridge so I picked a likely location for a hike and an exploration. Red Hill stands between the highway and the Thompson River. It rises 2400 feet from the rest stop to the top so I set out to explore the slopes on a sunny and hot day at the end of May.
I spotted the first bitterroot flowers on open patches of loose soil within 10 minutes and as I climbed I had to be careful where I stepped because there were thousands of emerging and blooming flowers. The blossoms only open in the sun so in the time from the start to the climb to the time for the hike back down there were even more, probably tens of thousands on the wide expanse of open slopes, especially those facing south and west.
If you can go there or to any sunny open hillside along that route, you will need to go soon, but if not put it in your calendar for next year. Here are a few shots taken from earlier in the week. Click a image for a larger view.
Here is an article on Bitterroot.