Noxious Weeds to Know for the California Supplemental Exam for Landscape Architects

Regulatory Agency Series: Part 7

California Department of Food and Agriculture and the Noxious Weed Program

You might think that the California Department of Food and Agriculture would have little to do with landscape architecture in California or preparing for the California Supplemental Exam for landscape architects.

It’s All About the Weeds

However, there is one area of responsiblity that the Department of Food and Agriculture that affects landscape architects: noxious weeds.

California Department of Food and Agriculture Mission Statement

To get a better idea about what the Department of Food and Agriculture does, here is their mission statement and goals taken from their website:

The California Department of Food and Agriculture protects and promotes California’s agriculture. California’s farmers and ranchers produce a safe, secure supply of food, fiber, and shelter. These commodities are marketed fairly for all Californians and produced with responsible environmental stewardship.

Here are the goals of the California Department of Food and Agriculture

  1. Ensure that only safe and quality food reaches the consumer.
  2. Protect against invasion of exotic pests and diseases.
  3. Promote California agriculture and food products both at home and abroad.
  4. Ensure an equitable and orderly marketplace for California’s agricultural products.
  5. Build coalitions supporting the state’s agricultural infrastructure to meet evolving industry needs.

Goal number 2 is the aspect of the department that affects landscape architects and our clients.

Noxious Weeds and Landscape Architecture

As landscape architects, we survey many different sites. some of these sites may have noxious weeds growing on them and threatening wildland and agricultural land.

California noxious weed laws place burdens on property owners:

5401. Any premises, plants, conveyances or things which are infected or infested with any pest, or premises where any pest is found, are a public nuisance, and shall be prosecuted as such in all actions and proceedings. All remedies which are given by law for the prevention and abatement of a nuisance apply to such a public nuisance.

Violations of the state’s weed laws can be punished with fines up to $10,000.

The California Department of Food and Agriculture is responsible for managing the Noxious Weed program.

Anyone who has a noxious weed growing on their property is technically creating a public nuisance.

Therefore, it is the property owner’s responsibility to remove noxious weeds from his or her site.

As a landscape architect, you may survey the site for noxious weeds during the site inventory phase. Landscape architects act as an agent of the owner and have a fiduciary responsibility to inform their client of noxious weeds that violate state law when discovered growing on a site.

In California, noxious weeds are assigned one of four categories: A, B, C, D, and Q.

Noxious weeds assigned an “A” or “Q” rating are the most noxious and possibly the most controllable weed species that warrant special consideration during the site inventory process.

Examples of Noxious Weeds in California

  • Artichoke thistle – Cynara cardunculus
  • Canada thistle – Cirsium arvense
  • Black acacia – Acacia melanoxylon

The current California noxious weed list is maintained at the California Encycloweedia site at

Noxious Weeds and the California Supplemental Exam

  • Landscape architect candidates need to know the following items for the California Supplemental Exam (CSE) for landscape architects:
  • California Department of Food and Agriculture maintains a list of noxious weeds that must be controlled
  • Clients can be fined for having “noxious weeds” on their property
  • It is against the law to sell plants that are noxious weeds or to violate quarantine laws
More information sources about California noxious weeds to help you prepare for the California Supplemental Exam, check out these links:

Noxious Weed Laws

For More Information on Regulatory Agencies:

  1. Part 1: Introduction to Regulatory Agencies on the California Supplemental Exam
  2. Part 2: US Army Corps of Engineers
  3. Part 3: Federal Emergency Management Agency
  4. Part 4: United States Fish and Wildlife Service
  5. Part 5: California Department of Fish and Game
  6. Part 6: California Environmental Quality Act (CEQA)
  7. Part 7: California Department of Food and Agriculture

Pass the California Supplemental Exam (CSE) for Landscape Architects e-book study guideIf you are looking for a study guide to help you prepare to pass the CSE the first time, check out Pass the California Supplemental Exam for Landscape Architects study guide e-book.


John is a landscape architect who is currently preparing to take the California Supplemental Exam to become licensed in California. He is currently a licensed professional landscape architect in Georgia and Florida. John graduated from California State University, Pomona with a BSLA degree in landscape architecture in 1997 and has extensive practice experience in residential and commercial landscape design.

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