Sweet Springs Trail is wonderful in all seasons, but especially throughout all the stages of spring. Trillium; hound's tongue; false & true Solomon's seal; delphinium/larkspur; columbine; pitcher sage; white globe lily; our rare Indian pink. I could go on. Try it!
Here is one more overview image of the trail, curving around the hill. Plus some of its flowers, here trillium and white globe lily.
Others of the flowers I list above, and more, can be found elsewhere in my collection. Especially, look in Jasper Ridge: "Adventures on a Smaller Scale" as well as "A Day at a TIme".