As part of its commitment to ecological landscapes, Penn has expanded on a Leave the Leaves initiative started in 2025 in select campus areas, allowing fallen leaves to remain in place during the fall season. The effort advances one of Penn's Climate & Sustainability Action Plan 4.0 goals to support biodiversity and a growing understanding that allowing fallen leaves to remain in targeted spaces can be a powerful investment in the health of our campus ecosystem.

How Leaving the Leaves Supports Campus Sustainability

Following a successful 2025 pilot, teams across the University now collaborate each year to select areas where natural leaf cover is both appropriate and beneficial. The approach aims to balance aesthetics and safety with ecology while collecting data to inform best practices in sustainable landscape management. As leaves in these locations decompose, the University can take advantage of a natural recycling process that:

• Returns vital nutrients such as nitrogen, phosphorus, and potassium to the soil;
• Creates important habitat for wintering wildlife, including beneficial insects that use leaf cover to survive the winter and re-emerge in the spring;
• Increases pollinators and birdlife, which depend on a diversity of plant and insect life; and
• Suppresses weed growth.

This effort may already be showing results, including signs of a growing lightning bug presence on campus on warm summer evenings. By allowing leaves to remain in select areas, Penn is taking a meaningful step toward protecting a healthy ecosystem and demonstrating environmental leadership in the face of a changing climate.

What to Expect in Designated Areas

Some areas will be designated as leaf-friendly zones, with signage placed in key locations to help identify them. This selective approach allows Penn to pursue sustainable practices in designated areas while maintaining the manicured appearance and safety of high-traffic walkways and primary campus corridors.

Here is what the seasonal cycle looks like:

• Fall/Winter: As temperatures drop and leaves fall, insects seek shelter within leaf litter in planting areas. Leave the Leaves areas are indicated with signage, while walkways and hard surfaces continue to be cleared.

• Spring: Once temperatures consistently rise above 50°F, insects naturally disperse. After snow melts and spring arrives, designated areas are tidied, leaving both the landscape and the insects in healthy shape.