Sunflowers – Genus Helianthus

Helianthus, the genus which includes sunflowers, is derived from the Greek words for “sun” (helios) and “flower” (anthos). Sunflowers may be perennial or annual plants. The helianthus divaricatus in this garden is one of several species of North American perennial sunflowers often collectively referred to as “woodland sunflowers”. In contrast, Helianthus annuus is the species name of the thick-stemmed annual with the huge single flower that famously turns to face the sun and is a garden favorite around the world.

Traditional use:

For thousands of years and across North and Central America, sunflowers have been highly valued by many cultures. They have been both gathered and cultivated, primarily for food. Most cultivated sunflowers were annual plants which would have looked similar to the today’s familiar garden flower. The seed was the most important part of the plant to those cultivating annual sunflowers. Sunflower seeds were eaten raw, cooked, ground into flour or the oil was extracted from the seeds and then used (Harveson, 2015).

At least one of species of perennial sunflowers, Helianthus tuberosus, was also cultivated by some indigenous peoples as a root crop. The most important part of Helianthus tuberosus was the potato-like tubers. Helianthus tuberosus continues to be cultivated today and the tubers are referred to as Jerusalem artichokes, sunchokes or sunroots.

Sunflowers figured prominently in Native American lore and ceremony. Dyes were extracted from sunflower petals and an there were array of medicinal uses for the plant ranging from cauterization and healing of wounds to the alleviation of chest pains (Moerman, 2009). As an example of the level to which sunflowers were revered, consider this recounting of the origin story of the Haudenosaunee (Iroquois) people’s ancestral seed bundle by Mohawk seedkeeper Rowen White:

Helianthus annuus, the common sunflower
Helianthus divaricatus, a woodland sunflower

Corn, beans, and squash are considered by the Haudenosaunee people to be special gifts from the daughter of Original Woman (Skywoman). As the story goes, when the daughter was dying in childbirth, she said that from her body would come the foods that would sustain the people. From her hands came the beans, from her breasts grew the corn, from her bellybutton grew the squash vines. From her legs grew the sunflowers, and from her head grew the sacred tobacco. From her heart sprouted the strawberry, and from her feet the original potato, known as a sunchoke.” 

-Emergence Magazine, Three Sisters by Rowen White, https://emergencemagazine.org/story/three-sisters/

A woodland sunflower leaf
A woodland sunflower root

Plant Characteristics:

Sunflowers are usually tall and many species can grow to six feet or taller. They bear one or more wide, terminal flower heads and the disks of these flower heads are made up of many little flowers though seeing these tiny flowers may be difficult without magnification. Sunflower lower leaves are opposite, often heart-shaped or lance-ovate, and almost always have rough, serrated edges. Most sunflower leaves are dark green. Most sunflowers have brilliant yellow petals. Many have hairy stems or leaves.

There is considerable variability across genus Helianthus. Wild sunflowers differ dramatically in appearance and habit from the cultivated tall, top-heavy plants plants that can paint a field golden. Wild sunflowers are most often perennials; cultivated sunflowers are almost always annuals. Perennial sunflower roots may develop tubers; the roots of annual sunflowers, though they may be deep, will not develop tubers. Perennial sunflowers prefer to spread by rhizomes while annual sunflowers preferentially spread by seed (Rhoades, 2020). Though distinguishing one wild species of sunflower from another can be confusing, identifying whether a plant is a sunflower is often straightforward.

Current use:

Most of the sunflowers now growing on the planet are annual plants, cultivated varieties of Helianthus annuus. Based on total sunflowers grown each year, sunflower’s role as a popular garden plant is far overshadowed by the number of sunflowers grown as an oilseed crop. Sunflower is the fourth most important plant-based oil crop in the world, following palm, soybean, and rapeseed (National Sunflower Association). Most of the market value of sunflowers is in the oil, whether that oil is eaten by people (or birds) as part of a whole seed or extracted from the seed then sold. Sunflower meal, left over after sunflower oil is extracted, is often added to livestock feed. The annual global sunflower market has recently been valued at over $7 billion USD.

Cultivated annual sunflowers are much more widely used than their perennial cousins, whose seeds, though also oil-rich, are too small and grow too sparsely for oil extraction to make economic sense. Cultivated Helianthus tuberosus, the perennial sunflower which produces the edible tubers called sunchokes, may be making something of a comeback as a high-end health food but remains a niche crop globally.

The cultural mystique of the sunflower remains intact although the its basis has morphed with time. Sunflowers have symbolized many things to many cultures and have recently become a modern symbol of peace and nuclear disarmament. Unusually, some sunflower varieties hyperaccumulate some heavy metals, meaning that some sunflowers have the capability to selectively absorb certain toxins from the environment if present. After the Chernobyl disaster, fields of sunflowers were planted to extract radioactive metals like cesium-137 and strontium-90  from the ground. The sunflowers successfully absorbed some pollutants and temporarily stored them in their plant tissue until they could be more safely managed. Using plants to clean up hazardous waste is called phytoremediation.


Stuff Almost Nobody Knows:

(for the perpetually curious)

Wild Helianthus annuus, the ancestor of cultivated annual sunflowers which has small seeds and a branched stem, looks more like its perennial cousins than its more famous descendants. That wild Helianthus annuus could more closely resemble its cousins than its descendants is a testament to the power of intentional plant selection over time. That selection process happened primarily in the United States and began more than 4000 years ago. Because the oil-rich seed was prized by the Native Americans, they likely selected the sunflowers with the the largest seeds for re-planting year after year. Over thousands of years, this selective pressure increased the size of the seeds by an order of magnitude (up to 1000%). Remarkably, all modern cultivated sunflowers can be traced to a single center of domestication in the interior mid-latitudes of eastern North America (Smith, 2013, Park and Burke, 2020). Now, of the major field crops grown today in the American Midwest, only sunflowers are native to the United States.

Cultivated sunflowers are not a problem-free crop. Diseases have always been a
factor limiting sunflower production and the emergence of new pathogens should be anticipated (Radanović et al., 2018). To expand the space available for cultivation, sunflowers may need to adapt to tolerate drier conditions, shallower soil, poorer soil or a shorter growing season. If a sunflower’s taproots can’t grow properly, the top-heavy plant has a hard time resisting strong winds. There may be variability in sunflower oil composition and some sunflowers may produce more preferable oil. In terms of the future potential for sunflower-based phytoremediation, not all sunflowers have the capability to accumulate heavy metals and those that have the capability perform unequally (Barnhart, 2019).

At present, most of the utility of genus Helianthus resides in a single species. Most of the genetic diversity resides in the perennial species that make up the bulk of those in the genus. Of the approximately 70 species in genus Helianthus, only Helianthus annuus and Helianthus petiolaris (the Prairie Sunflower) are annuals. Wild sunflower species are genetic sources of disease resistance in addition to other potentially desirable traits, and resistance genes have been successfully transferred to cultivated sunflowers (Radanović et al., 2018). We don’t know what we will need to ask sunflowers to do for us in the future or the conditions under which we will need them to succeed. The traits that make perennial sunflowers resilient may be needed in the future to support the continued success of their cultivated cousins. The dramatic journey of a single sunflower species, from wild Helianthus annuus to a $7 billion global industry, shows the degree to which sunflowers will adapt to meet human needs and wants. The broad diversity amongst sunflower species means that the sunflower which could cope with whatever challenges arise in the future probably already exists somewhere in North America.


Black Squirrel Farms strives for accuracy but everyone makes mistakes sometimes. We’re happy to update our information if needed. Please contact us if you spot an error or have a suggested edit, update or information inclusion. Help is welcome.

Black Squirrel Farms is not a provider of medical advice. We share information and ideas but do not make health recommendations for or against the use of any traditional medicinal plant for any reason.


References:

Barnhart, M. SUNFLOWERS TO THE RESCUE!, https://athensscienceobserver.com/2019/05/16/sunflowers-to-the-rescue/, The Athens Science Observer, May 16, 2019.

Elfers, Z. Sunroot, Sunchoke, or Jerusalem Artichoke – Helianthus tuberosus, http://www.nomadseed.com/2017/11/sunroot-sunchoke-or-jerusalem-artichoke-helianthus-tuberosus/#:~:text=strumosus%20the%20pale%2Dleaf%20woodland,of%20stem%20and%20leaf%20petioles., Nomad Seed Project, Nov 21, 2017.

Harveson, R., Sunflowers: Origin and Usage by Native Americans, https://starherald.com/farm_ranch/sunflowers-origin-and-usage-by-native-americans/article_f5b407ef-dc2d-5e49-864a-c9eb6cff73b0.html, Star Herald.com, Sep 20, 2015.

Moerman, D. Native American Medicinal Plants: An Ethnobotanical Dictionary, Timber Press, Inc., Portland, Oregon, 2009.

National Sunflower Association, All About Sunflower, History, https://www.sunflowernsa.com/all-about/history/

National Sunflower Association, World Supply, https://www.sunflowernsa.com/stats/world-supply/

Rhoades, H. Is My Sunflower An Annual Or A Perennial Sunflower, https://www.gardeningknowhow.com/ornamental/flowers/sunflower/is-my-sunflower-an-annual-or-a-perennial-sunflower.htm, https://www.gardeningknowhow.com, 2020.

Park, B. and Burke, J. Phylogeography and the Evolutionary History of
Sunflower (Helianthus annuus L.): Wild Diversity and
the Dynamics of Domestication, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7140811/, Genes vol. 11,3 266, Feb 29, 2020.

Radanović A, Miladinović D, Cvejić S, Jocković M, Jocić S. Sunflower Genetics from Ancestors to Modern Hybrids-A Review, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6265698/, Genes, vol. 9,11 528, Oct 30, 2018.

Smith, B.D. The domestication of Helianthus annuus L. (sunflower), https://pubag.nal.usda.gov/catalog/617224, Veget Hist Archaeobot 2357–74 (2014), 2013.