“Keep your face to the sunshine and you cannot see the shadow. It is what sunflowers do.” – Helen Keller
Helen Keller knew enough about the wisdom of this bright and beautiful plant to share it with others. While she understood and celebrated the sunflower’s ability to follow the movement of the sun, she could not have known of its power to cleanse the earth. Thanks to the wonders of science, we do now, and it is a beautiful and useful wisdom!
The sunflower, or Helianthus annuus, from the Greek helios, meaning “Sun,” is a powerful plant in the world of industry and art. There are few people in the world who would be unable to recognize its shining yellow face in a garden or field. This bright, cheerful flower has given us a delicious and hardy seed, a versatile cooking oil, leaves for cattle feed, a stem strong enough to make paper, and of course, much beauty. It has also, as of late, brought us something even more special: the ability to remove harmful toxins from our soil, helping us to more safely handle the earth around us and grow food for ourselves and our communities.
The sunflower is one of many plants that are now known to aid in “phytoremediation,” a process that employs various types of plants to remove, transfer, stabilize, and/or destroy contaminants in the our soil, water and air. Compared to other cleanup methods, such as soil excavation or pumping polluted groundwater, phytoremediation has become a clean, cost-effective and environmentally-friendly way to reclaim and reuse land that has been tainted by poisonous chemicals and heavy metals.
I was first introduced to phytoremediation and the role that sunflowers play in that process after my housemates and I to put a home garden in an area we knew to be moderately contaminated with lead. We did not know much about the science behind it but figured it was a good first step in making our garden a healthy, pollutant-free space. What we discovered was quite remarkable. The first year we did a soil test, we learned we had a low to medium contaminant level. That meant we could get away with growing and eating fruit bearing vegetables like tomatoes, eggplant, and snap peas, with little to no-risk (we opted not to grow anything but sunflowers, though, that first year). Only one year later, after planting the sunflowers, we had no recognizable levels of lead in our soil. That year we planted our first bountiful urban home garden.
It is important to note, we didn’t just plant sunflowers. We also amended our soil with compost and manure, which not only helped the sunflowers grow big and strong, but also aided in the process of phytoremediation and lead abatement. We were also fortunate to have started with relatively low levels of lead in our soil.
Almost as important as planting the sunflowers, though, was what we did afterward. After the sunflower season ended, we did not permit our sunflowers to decompose in our garden space or put them in the compost, as that would only have returned the contaminants into the newly cleansed land. Instead, we took them to the dump, and though the levels of lead concentrated in their stems, leaves, and flower heads would have been relatively low, we labeled them “hazardous materials,” just to be safe.
Sunflowers are not only able to absorb lead, but other dangerous heavy metals such as arsenic, zinc, chromium, copper, and manganese. Probably the most astounding example of phytoremediation was the use of a type of sunflower to clean up contaminated soil in the Ukraine following the Chernobyl disaster, one of the worst nuclear power plant accidents in history. Other communities from far and wide have learned about and employed the magic healing of sunflowers. “Project Sprout,” based out of Tulane City Center in New Orleans, focuses on planting bio-energy gardens that include plants like sunflowers as a way to remediate soil, yield a crop for bio-fuel production, provide green-collar job training and to support urban revitalization in neighborhoods of New Orleans that suffered devastating damage from hurricanes Katrina and Rita.
Sunflowers have an amazing capacity to not only transform the health of a space in your community, but also add beauty.
If you’re looking to clean up your soil, or just want to enjoy the beauty of these flowers in your garden, here are some great varieties to try:
Soraya — a nice bright orange sunflower that grows to about 6 feet with a single stem.
Ring of Fire — a multicolored starbust sunflower that’s around 3 to 4 feet tall.
Russian Mammoth — a beautiful yellow flower that can grow to be 8 feet tall!
Velvet Queen — red and orange with burgundy undertones and grows to an average of 5 feet.
Sherie Blumenthal is a Food Access Coordinator with Lots to Gardens, an urban gardening and community nutrition initiative sponsored by St. Mary’s Health System in Lewiston, Maine.