The Chino Hills State Park is an hour and a half drive from Los Angeles and is best known for its beautiful poppy fields. You can spot the chic poppy field already on the road to the park and on the easy Upper Aliso Canyon Trail. In addition to poppies, the area boasts other wildflowers, such as violet owl clovers, lupines, and dozens of other field plants.
Although the poppy flowering season is from February to September, the most intensive flowering month is March. The season of flowering depends on the amount of precipitation during the winter. Poppies bloom for a week or two. The California poppy is so popular there are national holidays held in honor of the flower: Poppy Day (April 6) and Poppy Week (May 13-18).
Another place worth exploring is just a short drive from Orange County and called Walker Canyon. The trail to the canyon begins at Lake St. and Walker Canyon Rd. The path is easy and well-maintained, not to mention it is supplemented by stunning fields of poppies around it. Walker Canyon poppy fields have become very popular during the last years, so it's better to plan your trip during a weekday.