GILPIN COUNTY — Hiking on Golden Gate Canyon State Park’s (GGCSP) Mountain Lion trail on a sunny summer morning is always a serene experience. Pale sunlight slowly illuminates Forgotten Valley and makes Tallman Pond shimmer. 

Early bird hikers who wander through the valley’s forests might also discover thorny plants with violet flowers and tall grass stalks with fuzzy lime green leaves. But these hikers may not realize that these plants are actually invasive weeds that disrupt many natural habitats throughout the Rocky Mountains. 

GGCSP alone has over half a dozen different species of invasive weeds disturbing natural resources within park boundaries, including Canada thistle, mullein, and knapweed.  

“All of those [weeds] can ruin habitat for native grasses and wildflowers,” Park Resource Technician Jake Murray explains. “They take over our fields and don’t allow anything else to  grow. They can outcompete anything… They’re hardy plants, so most of them will survive in low water years unlike the natives, and they’re very good at spreading seed.” 

All of the invasive plants that are found in the park are also considered noxious, meaning that grazing animals such as elk, moose, and deer either prefer not to eat them or get sick when they try. As a result, animals struggle to find food when noxious weeds crowd the native plants out. The collapse of these diverse plant ecosystems harms pollinators and birds as well. 

It’s a major concern for local conservationists like Gilpin County CSU Extension Director Jennifer Cook, especially given the resilience of these plants.  

“Noxious weeds are from Europe and Asia,” Cook says, “They’re not from the US, and they have no natural predators or anything else that will compete with them… so they can come up anywhere.” 

The weed situation in Gilpin has continued to grow even more concerning in recent years.  

“It’s gotten warmer up here in the past few summers, and I’ve noticed that more weeds that were never here are now here,” Cook says. “Cheat grass can spread wildfires really easily...I’ve been keeping an eye on it.” 

Considering the damage that noxious weeds cause and how easily they spread, the best way to protect the local ecosystem is to get rid of the invasives that have grown on our own properties. 

“Familiarizing yourself with the weeds that we have here and then removing them as soon as possible helps your neighbors avoid dealing with them, and it’s beneficial to the whole community,” Murray says. 

Helping people learn how to remove invasive weeds is often as difficult as it is essential. Fortunately, the Gilpin County Extension office provides environmental education, resources and expertise to any county residents who are looking for guidance.  

Being able to identify invasive weeds is the first step in determining whether a natural area needs treatment and how it should be treated, but this can be hard to do without extensive  background knowledge on plant identification. For example, American thistle may be confused  with invasive Canada thistle, and wrongfully removed. 

Golden Gate Canyon has hosted multiple volunteer events to get help pulling patches of invasive weeds, including a recent Run and Restore program that brought volunteers to pull Canada thistle on Mule Deer trail.

Photo courtesy of Tim Weighart

That is where the Extension office comes in. Those who are uncertain about the plants on their  property can seek out assistance from Gilpin Extension to identify the plants and decide on a removal plan.  

“I usually just say bring in a sample or email me a photo, because it’s hard to identify without actually seeing it,” Cook explains. “That’s the first step, identify the plant… And then after that, it really depends on what the best way to manage that specific plant is. Once [the resident] knows the plant, I’ll give them all the options: Anything from organic hand-pulling all the way up to herbicides, and then they can decide how they want to manage it.” 

Cook’s team even offers an herbicide checkout program, complete with guides on how to make the right mix of chemicals for treating different plants. Beyond spraying and pulling, some plants and properties may benefit from mowing, goat grazing, or a combination of multiple treatments.  

Always eager to avoid spraying in the park unless he absolutely has to, Murray has found success in treating plants with insects that will eat specific invasive species without harming native plants.  

“We usually get seed head weevils,” Murray says. “They’re specifically drawn to the knapweed… They eat the seed heads from the inside out, and that’s how they kill off populations of that species.” 

Those who are interested in helping with invasive plant removal at GGCSP or other public lands should refrain from doing so without explicit permission and direction from those areas’ managers, preferably through official volunteer programs. Parks staff members do not want native plants to be misidentified and pulled, and often have specific plans for treating their  noxious weeds.

The teams at Gilpin Extension and GGCSP will be hosting more volunteer-led weed pulls and educational events in the coming weeks. Gilpin Extension will host a Noxious Weeds Talk at  Gilpin County Public Library on August 8, and GGCSP will have another Run and Restore event  where trail runners can go for a jog before pulling and bagging weeds later this month.

To Cook, addressing the noxious weed problem is all about expanding public knowledge about the plants that have colonized the county. A broader natural education will be essential to the survival of Gilpin’s native species, especially considering the public adoration of prettier invasive flowers like oxeye daisy. 

“[Oxeye] and scentless chamomile both look beautiful,” Cook says. “They probably came here as ornamentals, and now they’re everywhere, and people don’t realize they’re weeds because they’re so pretty and they want to keep them around.” 

“A lot of people don’t even look at plants or think about plants. Their interests are in other places,” she concludes. “But just helping them know that there are educational resources here, even in Gilpin County, can be very valuable in starting to change those perspectives.” 

Gilpin County CSU Extension does extensive local work pertaining to invasive plants, fire mitigation, forest health, and more. They also maintain a public community garden and host a  variety of educational programming. Reach out to Jennifer Cook at Jennifer.Cook@colostate.edu or call 303-582-9106 with inquiries about their services for invasive plants, and don’t miss their Noxious Weed Talk at Gilpin County Public Library on August 8, 10:30 a.m. (bit.ly/4w62EGG)

Keep an eye on ggcsp.eventbrite.com for updates on the next Run and Restore event, coming in late August. Call 303-582-3707 for further information on the park’s natural resources, events and more.