Benefits of pollinator-attracting companionplants2 September 2021, by Helen White

Perennial companion plants are usually planted inpermanent rows alongside the crop. For example, therow of companion plants in the background attractspollinators to the cucumbers in the foreground. Credit:M.A. Arnold

A recent interdisciplinary research project abouthow pollinator-attracting companion plants helpincrease yield in some horticulture cropsshowcases the intersection of excellence whenresearchers from diverse fields combine research,teaching and extension efforts to solve scientificquestions.

What started with the intent to find alternative usesfor some of our native wildflowers and developingthose as potential commercial crops, blossomedinto so much more, said Michael Arnold, Ph.D.,professor of landscape horticulture in theDepartment of Horticultural Sciences and directorof The Gardens at Texas A&M University.

"We became interested in how these plants attract pollinators and support pollinator populations.Could the wildflowers be used not only as a

beautiful addition to the landscape but also attractpollinators? If grown close to or as companionplants to growing vegetables or fruits, could we pairsome of our usual annual flowers and perennialflowers with vegetable crops or fruit crops toenhance their yield?"

Former horticultural sciences doctoral student JohnMontoya, Ph.D., used plantings of cucumbers andhabanero peppers to study these and otherquestions pertaining to how various plantingtechniques and growing conditions could affectpollination and crop yield of seasonal plants.

For example, how do you economically justifyallocating field space to flowers and ornamentalswhile not reducing the overall crop yield? Plantingpermanent rows of perennial plants adjacent to thecrops creates a habitat for pollinators and otherbeneficial predators or insects all year. Intermixingannuals within the rows allows you to take theannuals out with the crop and not decrease thetotal space used by the vegetable crops. Thestudies also focused on learning what kinds andhow many pollinators visited the plantings and didthey differ according to the season or crop.

Arnold assembled an interdisciplinary team fromacross the College to support Montoya's research:

Horticultural experts: Arnold's specialty isornamentals. Larry Stein, Ph.D., professor andassociate head for Texas A&M AgriLife ExtensionService programs in the Department of HorticulturalSciences, offered expertise in vegetable crops andselections for Texas growing conditions.

Entomology experts: Juliana Rangel, Ph.D.,director of the Texas A&M Honey Bee Laboratoryand associate professor of apiculture in theDepartment of Entomology, is an expert inpollination, bees and honey bees. She helped setup the experimental design typically used forpollinator studies. Karen Wright, Ph.D., associate

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curator of the Texas A&M Insect Collection in theDepartment of Entomology, specializes in nativebee biology, curation and identification. She helpedresearchers and students identify and curate thespecimens they collected to look at biodiversity orthe number of species and individual pollinatorsthat came to each type of plant.

Agriculture economics experts: Marco Palma,Ph.D., professor and director of the HumanBehavior Laboratory in the Department ofAgricultural Economics, and Charles Hall, Ph.D.,professor and Ellison Chair in InternationalFloriculture, contributed a marketing perspective,helped to calculate the costs associated withvarious treatment combinations and what it allmeant in terms of profit or yield and aided studentswith survey work for consumer analysis.

"This project was the perfect example of howfaculty from different departments in the Collegecan come together to address novel questionsabout specific systems and produce somethingexciting and impactful," said Rangel.

Looking at production functions from an economicperspective involves targeted considerations.

"In this particular problem, we looked at theproduction cost of using these pollinatorcompanions to determine whether the yieldsgenerated really made up in terms of an increase inquantity," Palma said. "We also sought to identify ifthere were any adverse effects in quality and tounderstand if we needed to account for any otherfactors."

Montoya's research found that the yield of peppersand some cucumbers did increase whether usingannuals or perennials. In many cases, these yieldsoffset the use of land for the perennial plantings—awin-win situation since enhanced yields canincrease profitability. Increased profits can offsetthe costs of using pollinator-attracting companionplants. Ecosystem benefits associated withimproved pollinator habitat and food sources alsoincrease.

Teaching: Research results inspire morestudent-led projects

Data from Montoya's study led to other questionsthat became a series of student-led projects.

"People from research, teaching and extensionareas came together to foster the success of Dr.Montoya's project," Arnold said. "It also resulted inuseful information that then led to the next series ofquestions we answered. That's the whole point ofscience."

Three projects that resulted from the questionsinclude:

— Zinnia hybrids. Zinnias, often considered aneffective pollinator-attractor, did not perform well inMontoya's project. Danielle Merrell, anundergraduate student majoring in horticulture andentomology, studied commercial varieties of zinniasto find out why.

"She found interesting traits about the levels ofultraviolet fluorescence, color hues, nectar guidesand size traits in the flowers," said Rangel. "Shealso compared the pollinator visits to those flowersto correlate which flower types increase pollinatorvisitations."

Arnold said the zinnia hybrid used in the originalresearch project was selected for its disease andpest resistance. Merrell's study showed that, whenobserved under ultraviolet light, the floral nectariesof this hybrid had a more jumbled pattern than thewell-defined ones of the cultivars that pollinatorsvisited often. Her research identified better zinniacultivars to select if you want to attract pollinators.A paper she wrote on her findings has beensubmitted to a peer-reviewed journal.

— Wildflower selection. Selecting the bestspecimens of native plants that attract pollinatorsalso became a research focus. Kaitlin Hopkins, adoctoral student in horticultural sciences, studiedMexican Hat or tall coneflower, a native wildflowerin Texas. She found it to be a strong candidate foruse as an ornamental plant with pollinator-attractingproperties. Palma and Hall were advisors for theconsumer survey work on the project. BrentPemberton, Ph.D., a regents fellow in floriculture atthe Texas A&M AgriLife Center at Overton, helpedassess commercial viability relative to current

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bedding plant production practices.

Pollinators are attracted to Mexican hat or tall coneflower,a native Texas wildflower. Credit: M.A. Arnold

— Container plantings for urban areas. Horticulturalsciences doctoral candidate Jonathan Caplesinvestigated if Montoya's findings are applicable inurban environments. To do so, he developedmodular units of containers of varying sizes for abalcony, patio or backyard setting. Some of the pre-assembled units included combinations ofvegetables and pollinator-attracting plants, whileothers were designed for consumers to buy theindividual components for a do-it-yourself project.The largest unit is a 4-foot by 4-foot raised-bedgarden; the smallest is a 10-gallon containersuitable for a patio or balcony.

He worked with different combinations ofvegetables and pollinator-attracting plants for bothwinter and summer plantings to find the best onesto attract pollinators when fruits and vegetables areflowering at the same time as the pollinator-attracting plants. He also worked with Hall onsurveys to determine consumer preferences, suchas whether they prefer a certain kind of vegetablecrop or ornamental and what they would be willingto pay. Could the agriculture industry produce sucha product and sell it at a profit?

"Understanding what the consumer wants and thentrying to go back in the supply chain to providethose products is easier than growing what we likeand then trying to find a market for it," said Palma."It is crucial to know what the demand drivers are tobetter adapt our production practices andeverything else to satisfy that demand."

Caples continues to field test the potential for usingthese modular units in urban environments andverify pollinator-mediated yield impacts.

Undergraduate student workers and studentvolunteers involved in these projects learned aboutplot and statistical design setup—scientifictechniques associated with collecting various typesof data. With these research opportunities, theywere able to apply what they learned in theirclasses to a real-world setting, and accomplishedprojects with results that are relevant to consumersand industry.

Extension: Getting information to consumersand industry

Whether a homeowner growing plants for theirbackyard or a commercial operation making anoperational decision, consumers expect science-based information established by data andevidence. Studies such as the projects Montoya,Hopkins and Caples led, and the resulting undergraduate student participation, inform industryexperts about best practices and translate researchimpacts.

Montoya's dissertation paper, "Pollinator-attractingCompanion Plantings Increase Crop Yield ofCucumbers and Habanero Pepper," was publishedin the American Society for Horticultural Science,ASHS, peer-reviewed journal, HortScience. Itreceived the ASHS Outstanding ExtensionPublication Award for papers published in 2020.The selection committee is comprised of scientists,educators and extension personnel in ASHS.

Arnold said the award reflects the relevance andquality of the research coming from the College ofAgriculture and Life Sciences.

"A highly integrated network of people came

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together to accomplish goals none of us couldaccomplish individually," Arnold said. "That's thepoint of interdisciplinary work. Texas A&M AgriLifehas such diverse resources of expertise, it's hard tothink of an agriculture-related topic where wecouldn't call on the capabilities of people in variousdepartments to collaborate and find a solution."

More information: John E. Montoya et al,Pollinator-attracting Companion Plantings IncreaseCrop Yield of Cucumbers and Habanero Peppers, HortScience (2020). DOI:10.21273/HORTSCI14468-19

Provided by Texas A&M UniversityAPA citation: Benefits of pollinator-attracting companion plants (2021, September 2) retrieved 29November 2021 from https://phys.org/news/2021-09-benefits-pollinator-attracting-companion.html

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