Kennedy Grove Regional Recreation Area Yellow Mustard Flower Field taken on 03-28-11. Kennedy Grove Regional Recreation Area (one of the East Bay Regional Parks) is located near the San Pablo Reservoir in unincorporated Contra Costa County. I have been a lifelong resident of Contra Costa County and one of my favorite times of year is the spring when yellow mustard flowers appear in local parks, preserves, open spaces, empty roadsise lots....everywhere! I always notice them no matter where they show up! I don't think they deserve to be called "just weeds" by some people. To me they are beautiful wildflowers and brighten up any area with their presence. The sky was so blue this day and the clouds were perfect. I couldn't resist taking some photos. This is one of the first photos that I took after getting my DSLR and it's still my favorite. It cheers me up to look at it on rainy days. The yellow mustard flowers are like rays of sunshine reaching out to me and make me feel happy to be alive.