Can Goats Control Weeds at Lake Sammamish State Park?

At the Mountains to Sound Greenway Trust’s field base in Issaquah, a whiteboard for schedules and updates features a curious statistic: an ever-growing tally of how often restoration volunteers have asked, “Why not use goats to get rid of blackberry bushes at Lake Sammamish State Park?” It’s a fair question; digging out thick root balls and hauling thorny stems in a riparian forest is tough work, and progress can be hard to see given the incremental nature of the job.

Yet over the decades, the collective impact of volunteers on salmon habitat in the park and across the Mountains to Sound Greenway National Heritage Area has been monumental. Without the dedicated stewards who sign up for our restoration events, non-native blackberries would re-populate once-cleared areas, crowding out native trees and shrubs. And while it might be tempting to replace passionate stewards with efficient grazers, there’s a reason why we don’t rely on goats despite their gastronomic contributions to the world of habitat recovery and land management.

How Goats Are Utilized in Restoration and Land Management

Given the right circumstances, goats are great for managing weeds or dense understory vegetation. They’ve been used for wildfire prevention in Washington State, where their voracious appetites help manage vegetation that might otherwise become fuel for fires. Goats’ ability to traverse steep terrain also makes them a safer or more cost-effective option than using humans or heavy equipment to reduce wildfire risk.

Goats have been successfully utilized to reduce the biomass of blackberries, but not without the help of soil-turning mechanical masticators and weed-killing herbicide. In projects like these, restoration practitioners deploy goats early in the restoration process to tackle riparian habitats that are fully overrun by non-native species like blackberries. Without the presence of native plants, goats can be one of many tools used to decrease total cover of weeds to make space for future plantings. What separates Lake Sammamish State Park from other areas is that native species are deeply intermixed with non-native understory. Throughout many of the areas where we work in Issaquah Creek, invasive species like blackberry are intertwined with the native plants which poses a unique challenge and requires a more targeted, volunteer-led approach.

Why We Can’t Use Goats to Restore Issaquah Creek

Goats are widely, and mistakenly, believed to be willing to eat just about anything. Like many animals, goats have dietary preferences and can be picky eaters. When given the choice between chomping down on thick, thorny blackberry versus a woodier twin berry or succulent salal, goats prefer natives first.

At Issaquah Creek, non-native plants weave between the shrub-filled understory that flanks the sides of the stream and, if not cared for, can impact the overstory of conifers and hardwood that reach out and over the stream, providing shelter and nutrients for salmon. At complicated restoration sites like these where non-native blackberry grows around and over native plants, goats may overgraze or damage desirable native species in the removal process. This would directly undermine our goal of rebuilding healthy forests along Issaquah Creek.

While simply lopping, mowing, or grazing the tops of blackberries just encourages further growth, goats also don’t dig out root balls as they graze, leaving behind a part of the plant that can regrow and spread. Leaving the root ball, or even fragments of it, can enable the plant to resprout and spread all over again. Because goats’ eating habits can’t be controlled, they’re unfit for restoration work.

Why Volunteers Are Key to Long-Term Recovery at Issaquah Creek

For the past 20 years, we have worked alongside partners and volunteers to protect and restore habitats in and around Issaquah Creek. With a hatchery upstream, millions of juvenile salmon depend on this waterway to support various stages of their life cycle. Without the thousands of hours community members have dedicated to uprooting blackberries, we would not be able to complete all the work that needs to be done to protect and conserve native keystone species like salmon. This investment in weed removal, coupled with native plantings, has been successful in managing this persistent species. And though we cannot always see the impacts when we are literally in the weeds, volunteers’ efforts do influence the salmon that swim through Issaquah Creek.

Volunteers have been key to setting the stage for one of the biggest in-stream restoration projects ever completed at Lake Sammamish State Park. During the summer of 2025, 4,600 feet of Issaquah Creek was restored with over 500 pieces of wood and in-stream construction that re-opened a historic channel. Ahead of this huge in-stream project, stewards helped restore the land around the stream with over 70,000 hours of volunteer work.

There is still a plethora of work that needs to be done along the banks and within the forests that surround the stream, and we need help from the community to get it done. Pulling weeds will continue to be an essential task to create space for future native tree and shrub plantings that can support long-term riparian health, ecosystem function, and wildlife connectivity. Ultimately, restoring salmon habitat in the Greenway NHA is better served by environmentally conscious people, not on the hope that goats will develop a selective taste for weeds.

Become Part of the Solution

Volunteers who help manage the spread of weeds and ensure native trees and shrubs can mature preserve a delicate balance. The benefits of that work can already be seen in the regrowth of forests around the creek, but the benefits for both people and wildlife will last well into the future. Saplings will grow into towering adults to fill the creek with large woody materials that shade out non-native plants and become an essential part of an interconnected system, boosting the survivability of future salmon populations. As they navigate between the Puget Sound and their natal streams, salmon will give back to the native plants that helped shelter them as juveniles, while supporting wildlife and people along the way.

Community conservation is vital for habitats throughout the Mountains to Sound Greenway National Heritage Area to thrive. Help power the future of stewardship by joining an upcoming restoration event or donating to keep these projects moving forward.