Open Space & Native Landscape Management

The Marshall Fire in Boulder County has become the most destructive wildfire in Colorado history, destroying more than 1,000 homes and businesses and burning over 6,000 acres. Although the cause of the fire remains unknown, several uncontrollable factors contributed to the spread of the fire including wind gusts up to 120-mph and a prolonged lack of moisture.  

Denver Parks and Recreation (DPR) continually reviews technical research and open space management practices in the front range region. According to the Colorado State Forest Service, the majority of Denver is rated as “Low” to “No Risk” for Wildland-Urban Interface fires.  DPR has re-evaluated the open space management practices for the urban park system and confirmed, at this time, no changes are required regarding our current workplan and mowing procedures.

Fire Mitigation Efforts

Below are fire mitigation efforts managed through DPR:

• Maintain healthy native grasses, that are not mowed frequently to benefit open spaces and mitigate the potential of fires. Taller grasses hold moisture in the soils that keep plants from becoming dry earlier in the season, reducing fire danger in open spaces. If mowing occurs in open spaces, invasive species will encroach into an area and may have a high tendency to catch fire, making open space more vulnerable to fire.
• Enforce fire restrictions and fire bans within parks and open space with an emphasis during high wind advisories and periods of drought
• Provide education and outreach to residents on best ecological practices for landscape management
• Proactively research and evaluate the best management practices to maintain a healthy ecosystem while mitigating fire risks
• Maintain mowing management techniques to manage noxious weed species

DPR allows homeowners to mow tall vegetation on park-maintained property 3-feet from property owners fence line as a fire mitigation buffer zone. Vegetation must be mowed with the highest setting on the mower and no shorter than 6-inches. Mowing can only take place adjacent to the homeowner’s property boundary.

Property Owner Resources

Additionally, the following resources will assist with fire mitigation on private property:

• Remove or manage flammable vegetation, including dead or dry shrubs, slash, mulch, and other woody debris from around your home.
• Consider fire-wise plantings on private property (Colorado State Extension)
• Select fire-proof building materials for your home and fences (Ready For Wildfire)

Denver Parks and Recreation has five designated natural areas that are managed as special portions of open, undeveloped land that can provide beauty and comfort to the community. They tell us about the history of the land and region, its landscape, geology, and people.

1. Parkfield
2. Inspiration Point
3. Heron Pond
4. Camp Rollandet
5. Paul A. Hentzell

These natural areas were chosen for designation due to their native vegetation, wildlife habitat and community connections. Natural areas designations go through public review and are ultimately approved by the Parks & Recreation Manager.

Additional criteria are required of a site to become designated including:

• Provides or could provide protection for a sustainable natural ecosystem, wildlife habitat, native plant species and communities, geological formations, or water corridors or wetlands
• Serves as an example of a rare or unique native condition in an urban setting in need of ecological preservation
• Serves as an outdoor classroom or laboratory for scientific study or other educational opportunities for the public
• Functions as an area of biological diversity, natural beauty, and inspiration which meets aesthetic needs, and which enriches the meaning and enjoyment of human life

Things to know:

• Stay on the designated trails
• Properly dispose of all trash in a receptacle or pack it out
• Do not remove any vegetation or pick flowers
• Dogs must be on-leash at all times
• Always pickup after your pet
• Enjoy the natural landscape and wildlife views

Native landscapes support biodiversity by providing wildlife habitat and opportunities for nature play. The management of native species helps meet DPR's goals to reduce water use, improve water quality, and support the overall environmental health of the city by preserving the historic prairie landscape on which Denver was built.

Noxious Weeds

Noxious Weeds are non-native plants that threaten native landscapes and open spaces by disrupting ecosystems. Their presence affects waterways, wildlife, and recreation. They come to Colorado as seeds in ornamental planting mixes, as nursery stock or hitch-hikers on the undercarriage of vehicles, and have been transported from places as far away as Europe, Asia, and Africa. Their natural controls such as insects or diseases do not arrive with them and many species may still be sold in local nurseries for planting in ornamental landscapes.

DPR aggressively manages noxious weed infestations within urban natural areas, native landscapes and open spaces, as well as in Denver Mountain Parks. Management efforts lead to significantly reduced noxious weed populations which then allows for Colorado’s native plant species to thrive and improve biodiversity.

DPR also works to comply with the Colorado Noxious Weed Act which helps prioritize management efforts. The presence of noxious weeds is often a symptom of broader ecological/land management issues. By better understanding how natural and man-made disturbances contribute to the introduction and spread of noxious weeds, DPR is able to preserve and protect public parks.

Native Landscape Management

Native grasses provide wildlife habitat and are the foundation of natural ecosystems. Restoring and protecting native grass habitat is vital to preserving biodiversity and DPR uses an adaptive management approach to protect and enhance native grass populations. This approach focuses on monitoring and evaluating to inform management decisions and meet short-term and long-term natural resource goals. Other management components include removal of competition to native grasses. Invasive vegetation outcompetes native plants for sunlight, moisture, and nutrients. Selective mowing is incorporated into native grass management to maintain healthy populations. Timing of mowing is critical and will take place once every year or two years after establishment.

Learn more about DPR's Integrated Pest Management program.

Stream management is consistent throughout all communities in Denver. Weed management and debris removal generally occurs between October and mid-March. Taller grasses have become noticeable over the last 5-6 years due to the reduction in mowing, however, this allows more native vegetation the opportunity to outgrow undesirable invasive and noxious weeds. Mowing does not occur within a minimum of 50 feet between the stream bank and upland area, as the taller grasses provide structural integrity to the stream by forming a protective barrier between the flowing water and soil during storm events to reduce damage to bridges, properties, and parks.

In addition, healthy streams provide other benefits such as:

• Reducing pollutants like road oils and fertilizers to make stream water quality safer for play
• Reducing speed of water to increase safety to us during storm events
• Promoting green and thriving streams to enhance our recreation and outdoor experiences
• Increasing biodiversity by protecting and restoring native plant communities to support wildlife and create migration corridors