The results of the University Libraries One Seed program, a gardening project that shares red sunflower seeds with the community, are in full bloom on the University of Colorado Boulder campus. At almost 10 feet tall with the signature red pigments in the petals, the sunflowers fill three planters across campus including a container at the intersection of Broadway and Pennsylvania.

The red sunflower was discovered and cultivated in Boulder, Colorado by high school biology teacher Wilmatte Porter Cockerell and her husband CU Boulder professor Theodore Dru Allison Cockerell in 1910. Now more than 100 years later, CU Boulder faculty and staff are growing the flower on campus and in their own gardens thanks to STEM Engagement Librarian Abbey Lewis who started the One Seed program.

Thedore Dru Allison Cockerell was a professor of zoology at CU Boulder from 1904 to 1934. He was an internationally known naturalist who researched and published prolifically in zoology, botany, ecology and paleontology. He is best known for his work on bees. The CU Digital Library contains many of his research notes on species, letters to colleagues, films, lantern slide images and more.

“We started One Seed as a way to share the T.D.A. Cockerell Collection, a vibrant part of our archives with unique materials that relate directly to the university’s history,” said Lewis. “The compelling thing about the red sunflower is that it was made possible by two biologists being there with the knowledge and inclination to make it into something that could be shared with the world. That speaks to so many of the connections and endeavors that are possible at CU Boulder. For me, the red sunflower is emblematic of all the amazing new ideas and discoveries that happen here.”

Since the program started in 2021, Lewis and her team have distributed over 4,000 red sunflower seed packets, many in celebration of Earth Day.

“Earth Day was a great opportunity to share these seeds,” explained Lewis. “Sunflowers are native to the area and attract pollinators. Cockerell himself was an entomologist and he named thousands of species of bees. We have shared the seeds the past three Earth Days and folks will come back to the table and talk about the flowers they’ve grown and what they are planning. I always ask how high their flowers have grown or how red they are because there can be a lot of variation.”

With the success of the program, researchers and students have been more interested in seeing and interacting with the T.D.A. Cockerell Collection.

“We had one researcher come into the archives to see the collection who is researching seed programs and she was particularly interested in sunflowers,” said Lewis. “Academic programs have also invited me to classes to speak about the collection and share seeds. We’ve been seeing a lot of great interest and engagement.”

In addition to sharing the seeds at pop-up tabling events like Earth Day and class visits, Lewis has shared them with various groups on campus including the Herbarium, Environmental Center, the Farm and Garden Club and Outdoor Services in Facilities Management.

Christian Parker, horticulture and weed management supervisor in Outdoor Services, was one of the people Lewis shared the seeds with.

“Facilities Management was first contacted last year and asked if we would be willing to plant some Cockerell Red Sunflower seeds on campus,” said Parker. “After hearing the history of these sunflowers, I was excited to be a part of creating a display on main campus. At that time we chose four spots that we hoped would be good places for them to grow, however we were only successful in getting the seeds to germinate in one of those places. So at the start of this growing season we chose different locations and were much more successful in getting them to grow. We currently have three successful sites on main campus to view them.”

The red sunflowers can be found on the north side of the Regent building, the circle planter in the roundabout just southwest of the Baca Education building, and the circle planter on the campus corner of Broadway and Pennsylvania, southwest of the Hale building.

“When choosing sites for the sunflower this season, we took foot traffic, sun requirements, irrigation, visibility and aesthetic value into consideration,” explained Parker. “I looked for locations that would avoid potential picking or disturbing of the flowers, so that they could be enjoyed by all; areas where they could be easily and frequently viewed; locations that weren’t too close to one another so that viewers could walk comfortably to at least one area on main campus to see them; and lastly, locations that met the best sun, water and overall height requirements of the Cockerell Red Sunflower.”

Sunflowers can be easy to grow particularly if planted in the right conditions. However, for gardeners looking to increase their success rate, Parker offers some advice:

“Sunflowers grow best in full sun, however they can do reasonably well with at least 6 hours of morning sun or 4 hours of afternoon sun. They are quite happy in poor soil conditions, and will respond well in any Colorado soil, whether it’s been amended with compost/fertilizer or not. Although they are very drought tolerant, for the best and largest plants/blooms, I would recommend daily watering until they are about 2 feet tall, and then pulling back to 2 – 3 times a week watering schedule (depending on current temperatures). One important thing to consider is location. These plants have shallow roots, but also get to be ten feet in height. So finding a spot in an area that is protected from high winds will help ensure that they do not break off at the root.”

One Seed plans to offer seeds again on the days surrounding Earth Day in 2025 with dates to be announced in early April.

How high have your red sunflowers grown? We’d love to see your photos! Email libraries@colorado.edu to share with us.