Plants with Potential

Guayule (Parthenium argentatum)
Guayule (Parthenium argentatum)

One of the primary reasons humans cultivate plants is to satisfy an economic need for natural resources. In order for a plant to realize its full economic potential, it must not only fill an economic need but also do so in a cost-efficient manner.

There are several examples of plants which, because of their unique products, appear to fulfill an economic need. However, these plants may not do so in a cost-effective manner.

With development of improved agronomic practices and plant-processing methods, which lower the cost of production, some plants may eventually realize their full economic potential.

Another factor that may affect a plant’s economic potential includes the availability and price of competing products on the world market. This factor is beyond the control of domestic agronomists.

Drastic changes in world conditions, such as in times of natural disaster, severe economic recession, or wartime, can have a dramatic impact on the economic feasibility of natural resources. Crops with economic potential may move in and out of economically favorable conditions as world markets change and new markets develop.


Guayule (Parthenium argentatum) is a shrubby member of the Compositae family that is native to the desert regions of the southwestern United States and northern Mexico. Other species of this genus are found in all regions of the Americas.

Guayule (Parthenium argentatum)
Guayule (Parthenium argentatum)

Guayule is one of more than two thousand plant species that can potentially be used to produce latex and rubber. Only guayule and its chief competitor, Hevea brasiliensis, have been used to produce commercial quantities of rubber.

Although commercial production of guayule-derived rubber dates back to the 1920’s, when Continental Rubber Company produced small quantities of latex and rubber from guayule plants grown in Arizona and California, it was not until the Emergency Rubber Project during World War II that large-scale production of guayule rubber commenced.

With the U.S. economy on a war time footing and with supplies of imported Hevea rubber becoming uncertain, U.S. Code Title 7, Section 171, authorized the U.S. Department of Agriculture to acquire the technology of the Continental Rubber Company, plant up to 500,000 acres of guayule, and develop factories for the production of guayule based rubber.

With the end of World War II and reestablishment of the Hevea rubber supply from Asia, guayule-based rubber was no longer economically competitive.

The unfavorable price difference between guayule-based rubber and Heveabased rubber has remained unchanged, even though many agronomic improvements have been made for guayule.

However, new life may be developing for guayule-based rubber in a large niche market: medical products. A method for producing hypoallergenic latex derived from guayule has been developed and patented by the U.S. Department of Agriculture.

A private company, Yulex Corporation, has licensed this technology and intends to use it to manufacture medical items, such as surgical gloves.

The gloves produced from guayule-based latex do not contain the allergenic proteins that Hevea-based latex contains, so they will not cause allergic reactions in the estimated twenty million Americans who are allergic to Hevea rubber products.

In this case, the cost disparity between Hevea rubber and guayule rubber is offset by the technical improvement that guayule latex brings to the high-value market for medical devices.


Jojoba (Simmondsia chinensis)
Jojoba (Simmondsia chinensis)

Jojoba (Simmondsia chinensis) is a woody, evergreen desert shrub that, despite itsmisleading species epitaph, chinensis, is native to the southwestern United States.

In cultivation, jojoba may be irrigated during its two- to three-year establishment period after which, assuming that the roots find groundwater, the plants do not require irrigation.

During the plant’s initial production period of three to ten years, the female plants may produce 350 kilograms of seeds per hectare. After ten years of growth, the plants may yield 500 to 800 kilograms per hectare for many decades.

Jojoba oil is extracted from jojoba seeds and comprises approximately 40 to 60 percent of the mass of the seeds. Jojoba oil is not really an oil per se, as it is not a triglyceride; jojoba oil is a plant wax similar to plant cuticular waxes, being composed of long chain alcohols and fatty acids.

The value of jojoba oil comes from its desirable stability. Jojoba oil is stable up to 300 degrees Celsius and does not become rancid even after decades of storage. Also, jojoba oil is very similar chemically to the highly prized sperm whale oil, so it is useful in cosmetics.

Jojoba oil was first produced in commercially important quantities during World War II, as a high-temperature lubricant and an extender for petroleum-based lubricants.

These jojoba-based products were used for engines, machinery, vehicles, and guns. As seen with guayule, the economics of jojoba oil production did not compare favorably with abundant petroleum products after World War II, so production of jojoba oil decreased sharply after the war.

In recent decades, the economics of jojoba oil production has gone through many fluctuations. In the 1970’s the Green Revolution reignited interest in renewable, natural resources, especially products that could replace petrochemicals and animal-derived products. Growers took advantage of tax incentives to start farming jojoba.

Then the disappearance of tax incentives and the decade-long production time to achieve commercially useful quantities of jojoba seed proved to be economically disastrous for many growers.

Many jojoba farms shut down operations. In the 1990’s the price of jojoba oil ranged from $40 per gallon to $200 per gallon, an unacceptable fluctuation in price that discouraged many industries from becoming dependent on jojoba oil.

The price of jojoba oil must stabilize before industries can once again explore adding jojoba to their lines. Additionally, some unique, value-added products containing chemically modified jojoba oil are becoming common in many upscale health and beauty products.


Hesperaloe (Hesperaloe funifera)
Hesperaloe (Hesperaloe funifera)
Hesperaloe (Hesperaloe funifera) is a plant in the agave family that produces long, thin fibers that may be processed into exceptionally light and strong paper.

Long-term biomass production studies began on hesperaloe in 1988, and since then many agronomic and processing improvements have been made.The fibers of hesperaloe seem suitable for the production of high-value products, such as ultralight coated papers.


Kenaf (Hibiscus cannabinus) is another fast-growing fiber crop that is finding utility in niche markets. Kenaf may be used to produce bright white paper, building materials, and absorbent materials.

Additionally, the black lignin liquor, a by product of kenaf processing, may add value to the crop by functioning as a binder for animal feeds, a fertilizer, or a termite-resistant coating.


Lesquerella (Lesquerella fendleri)
Lesquerella (Lesquerella fendleri)
Lesquerella (Lesquerella fendleri) is an industrial crop under development for its unique seed oils. Initial research indicates that domestically produced lesquerella may eventually replace imported castor oil in many cosmetics, pharmaceuticals, and industrial products.

Enhanced agronomic techniques, processing methods, conventional breeding, genetic engineering, and emerging niche markets may one day push lesquerella and other plants with potential into the realm of commercial viability.