Could greening reduce violent crime in Baltimore?

In light of the ever-increasing Baltimore murder rate, Mayor Catherine Pugh and gubernatorial candidate Ben Jealous took to the streets of West Baltimore last week for an anti-violence walk. As reported by The Baltimore Sun, their conversation included discussion of policy solutions to address violence, including gun courts and Safe Streets. There is another tool, however, that continues to be underused by City Hall and the state: greening vacant lots through the planting of grass, trees and other plants – then maintaining them.

While the idea lacks the powerful connotations of gun courts, it is a proven, effective strategy. Researchers at the University of Pennsylvania conducted a quasi-randomized controlled study in Philadelphia that looked at the effects of greening vacant lots on gun violence. The lots were cleared of trash and debris and greened, and a low, open fence was constructed around the perimeter to help prevent dumping. Furthermore, the lots received regular maintenance.


Neighborhoods that received the intervention had statistically significant decreases in gun violence.

The benefits, however, go further. In another nearly identical study that was recently published in the Journal of the American Medical Association, residents in Philadelphia neighborhoods with the intervention experienced significant improvements in mental health. Feelings of depression declined by approximately 42 percent, and self-reported poor mental health went down by nearly 63 percent.


Gov. Larry Hogan launched project CORE in 2016 as a means to address violent crime in Baltimore by tearing down nearly 4,000 blighted, vacant row homes. Their lots, however, remain. For residents living near vacant lots, the lack of maintenance is a constant frustration and detriment to their neighborhoods. It is often near these lots that we witness the drug dealing and crime that takes place in our communities.

In my own neighborhood in West Baltimore, we are left repeatedly petitioning 311 to cut the grass and remove trash. Due to frustrations with the long delays in maintenance by the city, our neighborhood association purchased its own lawn mower. While voluntarism has its benefits, the task of maintaining all the vacant lots in our community is beyond us. Indeed, the problem of maintenance of green spaces in West Baltimore goes beyond just vacant lots.

There are areas on the northern edge of Druid Hill Park that have years of trash hidden beneath the tree canopy. And residents in the communities along Gwynn’s Falls Parkway bear witness to decades of neglect of a piece of landscape architecture that is considered a local landmark. The Baltimore Green Network Plan, which will hopefully be adopted by the city this year, is a step forward in addressing these problems, though it is without funding.

Greening vacant lots and maintaining green spaces may be tools to help prevent violence in Baltimore, but like our own experiences with oil changes or a trip to the dentist, prevention is not glamorous. The same is true about prevention on a governmental scale, meaning it often gets low priority. For example, Baltimore is willing to pay the police department $21 million in overtime for combating crime that has been committed but appears unwilling to spend the money to create a sustainable, funded mechanism for the improvement of vacant lots and maintenance of green spaces that would help prevent crime in the first place.

Certainly, no single intervention is sufficient to address violent crime in Baltimore. A successful strategy to combat violence requires both prevention and the enforcement of law. We cannot merely green and maintain our way to a lower murder rate. However, there is value in using evidence-based policies that focus on prevention as they often have significant returns on investment. In fact, there is convincing evidence that the greening and maintenance intervention described above is affordable, scalable, reproducible and high-value.

The mayor and gubernatorial candidates care about violence in Baltimore. They are discussing the issue. The solution to the violence, however, will not be found in the courts or in a single program. It will be found in building strong communities, neighborhoods that are composed of people and their places. The research above demonstrates that investing in the maintenance of the places where the people of West Baltimore live would yield diverse improvements in the safety, health and wellbeing of the people who live there.

Dr. Daniel Hindman ( is a fellow at Johns Hopkins in the Division of General Internal Medicine.