This document provides background and citations for the key impact statements on the poster Native Plants, Stronger Communities.

1. Oak trees host 500+ species of moths and butterflies alone

Native oak species (Quercus alba, etc.) are ecological powerhouses. Research from Doug Tallamy shows they support over 530 species of Lepidoptera, making them among the most valuable trees for wildlife.

Tallamy, D. W. (2007). Bringing nature home: How you can sustain wildlife with native plants. Portland, OR: Timber Press.

University of Delaware, Tallamy Lab. (n.d.). Host plants. Retrieved from https://www.udel.edu/

2. Attract monarchs, hummingbirds, fireflies, and more!

Native plantings increase sightings of charismatic species like monarchs and fireflies. Even small patches of milkweed, goldenrod, and bee balm can restore habitat that supports these declining species.

Tallamy, D. W. (2019). Nature’s best hope. Portland, OR: Timber Press.

National Wildlife Federation. (n.d.). Garden for wildlife. Retrieved from https://www.nwf.org/

Xerces Society. (n.d.). Pollinator conservation resources. Retrieved from https://www.xerces.org/

3. Restore critical habitat with every yard transformed

Doug Tallamy’s 10-acre yard in Pennsylvania hosts over 1,300 species of moths, showcasing the profound biodiversity that can return with native restoration.

Wild Ones. (2021). Gardenside chat with Doug Tallamy. Retrieved from https://wildones.org/gardenside-chat-doug-tallamy/

4. Limit exposure to harmful pesticides linked to cancer and childhood leukemia

Studies link lawn pesticides like 2,4-D to increased risks of non-Hodgkin lymphoma and leukemia in children, especially with repeated exposure. Research also suggests certain pesticides and herbicides may exacerbate or trigger asthma symptoms, particularly in children and those with pre-existing respiratory conditions.

Niehoff, N. M., et al. (2021). Residential pesticide exposure and risk of childhood leukemia: A systematic review and meta-analysis. Environmental Pollution, 285, 117168. https://doi.org/10.1016/j.envpol.2021.117168

U.S. Environmental Protection Agency. (n.d.). Ingredients used in pesticide products. Retrieved from https://www.epa.gov/

Salameh, P. R., Baldi, I., Brochard, P., & Raherison, C. (2003). Respiratory symptoms in children and exposure to pesticides. European Respiratory Journal, 22(3), 507–512. https://doi.org/10.1183/09031936.03.00047803

5. Neighborhoods with more vegetation have up to 25% less air pollution

Vegetation reduces fine particulate matter (PM2.5), lowering asthma rates and improving cardiovascular health.

Nowak, D. J., et al. (2014). Tree and forest effects on air quality and human health in the United States. Urban Forestry & Urban Greening, 14(3), 441–448. https://doi.org/10.1016/j.ufug.2015.05.011

Environmental Health Perspectives. (2015). Retrieved from https://ehp.niehs.nih.gov/

Lovasi, G. S., et al. (2008). Children living in areas with more street trees have lower prevalence of asthma. Journal of Epidemiology and Community Health, 62(7), 647–649. https://doi.org/10.1136/jech.2007.071894

6. 20 minutes in a green space improves well-being by 60%

A 2019 study found a 60% well-being increase after 20 minutes in a park.

Hunter, M. R., et al. (2019). Urban nature experiences reduce stress in the context of daily life based on salivary biomarkers. International Journal of Environmental Health Research, 29(4), 1–11. https://doi.org/10.1080/09603123.2018.1497148

Dockrill, P. (2019, March 1). Spending just 20 minutes in a park makes you happier. TIME. Retrieved from https://time.com/5539942/green-space-health-wellness/

7. Capture up to 5× more CO₂ with native landscapes

Native prairies sequester up to 1.8 metric tons of CO₂ per hectare annually.

Honeywood Garden Design. (2023). The carbon sequestering power of native pollinator gardens. Retrieved from https://honeywoodgardendesign.com/blog/the-carbon-sequestering-power-of-native-pollinator-gardens

Natural England. (2012). Carbon storage by habitat: Review of the evidence of the impacts of management decisions and condition of carbon stores and sources. Natural England Research Reports, NERR043.

8. Use 60–80% less water compared to traditional lawns

Native gardens reduce outdoor water use significantly after establishment.

California Native Plant Society. (n.d.). Save water with natives. Retrieved from https://calscape.org/

U.S. Environmental Protection Agency. (n.d.). WaterSense. Retrieved from https://www.epa.gov/watersense

9. Replace gas-powered lawn equipment to reduce emissions equivalent to 234 million cars

Gas-powered equipment emits significant CO₂ and particulates; California’s phase-out is projected to cut emissions dramatically.

U.S. Environmental Protection Agency. (n.d.). Lawn and garden equipment emissions. Retrieved from https://www.epa.gov/

Carbon Credits. (2022, October 21). California’s bold shift: Say goodbye to carbon-emission gas-powered lawn mowers by 2024. Retrieved from https://carboncredits.com/californias-bold-shift-say-goodbye-to-carbon-emission-gas-powered-lawn-mowers-by-2024

10. Save hundreds per acre in lawncare maintenance

Ecological landscaping requires fewer inputs, lowering costs for homeowners and municipalities.

University of Maryland Extension. (n.d.). Conservation landscapes. Retrieved from https://extension.umd.edu/

Sustainable Sites Initiative. (n.d.). Cost comparisons. Retrieved from https://www.sustainablesites.org/

11. Lower chemical and water bills

Native plants reduce the need for pesticides and irrigation, cutting recurring costs.

U.S. Environmental Protection Agency. (n.d.). Green infrastructure benefits toolbox. Retrieved from https://www.epa.gov/

Audubon Society. (n.d.). Native plants reduce water use. Retrieved from https://www.audubon.org/

12. Eliminate up to 35 million tons of yard waste annually

Native plantings produce less yard waste than traditional lawns.

U.S. Environmental Protection Agency. (n.d.). Facts and figures about materials, waste and recycling. Retrieved from https://www.epa.gov/facts-and-figures-about-materials-waste-and-recycling

13. Reflect shifting homeowner priorities as native plant sales rise by 60%

Native plant sales and eco-friendly landscaping demand have surged.

National Gardening Association. (n.d.). Garden trends report. Retrieved from https://garden.org/store/view/15/National-Gardening-Survey-2023-Edition/