Landscape Architect Articles

Donated Passion Fruit Vines05-10-23 | Feature

Donated Passion Fruit Vines

Passion Fruit Vines Reduce Particulate Matter
by Joseph Gallegos, Grey4Green

With the growing trend in many areas to reduce water use, landscapes are being converted to dry or xeriscapes. An unintended consequence is that dust and contaminants are not being filtered by the landscape and are causing breathing and other health issues, especially to those living or working in areas close to roadways or increased activities. This EPA graphic shows how small PM2.5 and PM10 really are in comparison to human hair.

To find a way to reduce particulate matter using water efficient plant material, Joseph Gallegos of Grey4Green has donated his time and plantings of passion fruit vines to set up a test site to find a way to keep particulate matter at bay.

The vines were planted every 10 feet and grew into a solid, particulate capturing barrier.

At Grey4Green, we enjoy giving back to the communities in which we work. Our latest project is quantifying how passion fruit vines can be used to reduce particulate matter 2.5 and 10 (PM2.5 and PM10) pollution in the air around homes and businesses. Particulate matter is small, microscopic dust from car tires, brake pads, and other urban activities. Typically, green landscapes help sequester this particulate matter on leaves that eventually fall to the ground and become part of the soil ecosystem. The issue is that a lot of our landscapes are going dry or being transitioned to native, dry landscapes.

PM2.5 and PM10 are so small they can pass through blood vessels, and recent research shows there is a correlation to increased risk of dementia and pregnancy complications. Communities that border freeways are especially at risk, so the team and community partners came up with a strategy. If they could quantify how much particulate matter is collected per square yard of passion fruit vines, they then can determine the total green walls needed in an area to reduce overall particulate matter floating around in the atmosphere. The team selected passion fruit vines as the baseline plant, as it supplies a homeowner the benefit of edible fruit while the dense vines help shade the building. Most homes in disadvantaged communities do not use air conditioning because of the high utility cost, so this added shading offers a holistic way to cool homes.

One of the biggest roadblocks of adoption is the cost of water, so they used their skill set to show homeowners how to use greywater to grow these lush green walls. At the end of the project, we will have a baseline measurement we can compare to other vines and plants, and then offer a plant palette homeowners can use around their homes to provide multiple benefits. The same plant palette can be used by landscape architects to provide a healthier outdoor area for commercial building residents. In the winter of 2022/2023, they are installing over 80 passion fruit vines and 25 air monitors to record changes in particulate matter.

Our vision is to take urban centers natural resources (vertical walls and greywater) and use them to improve the area for all.