Toxic Roundup Herbicide, Fruiting Blackberry

The SFRPD’ Natural Resources Department (NRD) is spraying toxic herbicides on Golden Gate Heights park. The pesticides being used are Roundup (glyphosate) and Polaris (imazapyr). Someone recently saw this notice:

Sign indicating pesticide spraying Golden Gate Heights, San Francisco, Sept 2021

On the next visit, the sign indicated that the spraying had been completed on September 2, 2021.

Toxic herbicide notice - imazapyr and glyphosate - Golden Gate Heights San Francisco CA, showing spraying was completed.What’s really bad about this is that one of the target plants is blackberry. Now, while it’s fruiting season.

Blackberry bushes with ripe and unripe fruit


Back in 2017, we caught another such instance, at that time on Mount Davidson. We wrote to the Commission for the Environment in protest, and we published an article here with the details: Pesticides on Blackberry in the Fruiting Season

Here’s what we wrote then: “It’s the time of the year when the blackberry bushes bear fruit, to the delight of children and the public in general (and not a few animals and birds)…. NRD seems willing to go by the letter of the rules, not the spirit of it. Blackberry should not be treated with persistent herbicides at all, especially not in the fruiting season. It’s going to affect children, wildlife, and anyone who loves picking the berries in season… most parkgoers.

At the time, they used only Tier II herbicides. (SF’s Department of the Environment has a three-tier rating system for herbicides: Tier III, Least Hazardous; Tier II, More Hazardous; Tier I, Most Hazardous.) This time, according to the signs, they have used both imazapyr, which is Tier II and Roundup, which is Tier I.


In 2016, the SF Department of the Environment engaged in a lengthy process of trying to improve its restrictions on  some of the most problematic use of pesticides in our parks. (You can read the entire compliance guidelines here as a PDF. It’s from the SF Environment website.  sfe_th_ipm_compliance_checklist – Copy )

Among them, they developed these restrictions:

✓ A written recommendation from a licensed Agricultural Pest Control Advisor (PCA) is required for any pesticide use. Departments that do not have PCAs on staff should contact the SF Environment IPM Manager.

✓ Only pesticides on the current SF Reduced Risk Pesticide List may be used. Usage must fall within the “limitations” listed for each product, along with label requirements.

✓ ‘Most hazardous’ (Tier I) herbicides have special limitations:

  • Use is prohibited for purely cosmetic purposes.
  • Use is prohibited within 15 feet of designated paths. If a park map exists, designated paths are those found on the maps. Otherwise, designated paths are those actively maintained by staff.
  • Use is prohibited within 15 feet of schools, preschools, playgrounds, or other areas frequented by children.
  • Use on blackberry bushes is prohibited when fruit are present 
  • If within the City limits, use requires onsite supervision by a licensed person (PCA, QAL/QAC) o No broadcast spraying with a boom is permitted except for golf courses (targeted spraying only)
  • Certain pesticide use is restricted in designated Red-Legged Frog habitat, which includes Golden Gate Park, Lake Merced, and several other areas in San Mateo and Alameda County.

Clearly, NRD doesn’t care about the preferences of park-goers, who enjoy picking these berries, or it wouldn’t be trying to spray them in the fruiting season.

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