Notes from the Field: Edible Invasives

Wild mustard grows at MLK Shoreline in Oakland.

Walking down the path along the MLK shoreline or the Palo Alto Baylands you may be passing a pantry of invasive plants. In fact many invasive species crowding out our native California species have edible parts. Fennel, mustard, Himalayan blackberry, and wild radish are just a few examples of numerous invasive species taking over ecosystems around the Bay.

It’s not just coincidence that these plants are edible to humans. As the first European settlers brought mustard seed and fennel to grow in their fields, they were introducing plants to a whole new world of potential with few threats to their spread. These plants, foreign to the native flora and fauna, have little to no limiting factors (i.e. predators, disease, intolerable climates) that would otherwise keep their populations in control. Now in our efforts to restore coastal marshes around the San Francisco Bay, part of our work is to remove these invasive species.

mustard from the marsh
Mustard made from invasive mustard seeds collected at MLK Shoreline.

The next time you find yourself cruising the shoreline, try to identify some of these edible invaders. You can even try cooking with these plants (as long as you properly identify them). Our former Restoration Specialist Crescent Calimpong made four different kinds of mustard from seeds collected at our restoration sites around the Bay.

Here are some recipes for making your own country mustard and some wild fennel seed cookies:

Homemade Yellow Mustard

  • 1/2 cup yellow mustard seeds
  • 3/4 cup apple cider vinegar
  • 1/3 cup water
  • 1 1/2 tsp. sugar
  • Your pick of spices (honey, horseradish, fresh herbs), all optional

1. Soak the mustard seeds in the vinegar and water, making sure the seeds are covered by the liquid. Leave soaking for 2 days.
2. Transfer the mixture to the bowl of a food processor and process, stopping occasionally to scrape down the sides of the bowl with a rubber spatula, until the seeds are coarsely ground and the mixture thickens, about 3 minutes
3. Add the sugar and spices to the seeds mixture. Begin with about 1 tsp. of each spice. Blend mixture until it reaches desired consistency, adding water if needed. Add more spice to taste.

Wild Fennel Seed Cookies

  • 2 cups sugar, divided
  • 2 teaspoons fennel seed
  • 1 cup butter, softened
  • 2 eggs
  • 1 tablespoon orange juice
  • 1 tablespoon water
  • 1 teaspoon vanilla
  • 1/2 teaspoon baking powder
  • 1/2 teaspoon salt
  • 4 cups flour


1. Preheat the oven to 350°F. In a blender, briefly whirl together 1 cup sugar and the fennel seed to break up some of the seeds. In a large mixing bowl, thoroughly cream together the blended fennel-sugar, the remaining cup of sugar, and the butter. Add the eggs, orange juice, water and vanilla, and mix briefly.
2. In another bowl, mix the baking powder, salt and flour. Add the dry ingredients to the creamed ingredients and mix well. The dough will be stiff.
3. Divide the dough into four pieces and form each into a flattened ball. On a floured surface, roll each ball 1/4-inch thick and cut out shapes. Place them on greased or nonstick baking sheets and bake about 8 minutes, or until the cookies are light brown.

Happy foraging!