The Napa Valley from end of January through the month of March is covered with golden blankets of mustard.
There are references that mustard grains being cultivated by the Chinese over 3,000 years ago and it was a common seasoning for the Egyptians, Greeks and Romans. According to documents from Monterey County, Father Serra came from Spain to Mexico, bringing mustard seeds from Spain. He scatter mustard seeds to help mark their trail from mission to mission as they worked their way up the California coast. He and his Indian guides scattered them in the Napa Valley. The mustard trails and vineyards by the missions started over 230 years ago are still present from San Diego to Sonoma.
The hearty plants grow low to the ground and are considered beneficial cover crops. They help add nitrogen back to the soil, creating healthy vines and preventing erosion.
On Highway 29 you can enjoy the scenery and stop at lunch at Mustard Grill (http://mustardsgrill.com/) or Brix (http://www.brix.com/).