Sitting off the coast of Ventura and Santa Barbara are the Channel Islands. The furthest island east, the smallest sliver on a map, is Anacapa Island which, if we're being honest, is a misnomer. What's been designated as "Anacapa Island" by the National Park Service is actually three small islets: East, Middle and West Anacapa Islands. In total, they have about one square mile of space.
East Anacapa is the largest of the trio, and therefore offers the most to do for visitors. There's a visitor's center with history about the island, a light station from 1932 that includes an original lead-crystal Fresnel lens in the lighthouse, and a two-mile series of trails. Visitors can use these trails to view the native wildflowers which are currently in peak bloom. The giant coreopsis are the highlight. (The island is also home to the largest gull breeding colony in the world. Which is both a highlight and a fun bit of terror.)
You can get to Anacapa a few ways: Private plane or private boat, if you have the cash to spare. Or, if you're like the rest of us, you can get there via public boat. (A fare schedule can be found here.) If you're heading out there specifically for the wildflower bloom, you have until March or so if you want to see them at their fullest.
As always, call the visitor center before you go, if flowers are the goal. (805) 658-5730.