South Texas Natives

A publication of the Caesar Kleberg Wildlife Research Institute 2006 at Texas A&M University-Kingsville Volume 4, Issue 1

Native Plants Need Soil Microbes

By Larry Zibilske, Ph.D.

Native plants live in very com- petitive circumstances. They have “learned” many tricks that allow them to compete with other plants, harsh environments, insects, and diseases. In addition to their own strengths, they can take advantage of opportunities presented by growing in proximity to other plants, or in association with other organisms that result in a survival advantage. Relationships with other organisms can make all the difference in survival of particular plants. Many of these relationships are fairly well © Forrest Smith documented, but it is the relationships Native grasses such as (left to right) Rio Grande bristlegrass (Setaria ramiseta), between plants and soil microbes that Arizona cottontop (Digitaria californica), slim tridens (Tridens muticus), and pink pappusgrass (Pappophorum bicolor) have fibrous root systems. are arguably the most poorly under- stood—but may be among the most important. root zone microbes, collectively called seeded croton, Croton monathogynus) Soil microbes form several close rhizosphere microbes, is their antago- tends to favor clay soils high in caliche. relationships with plants. Their rela- nism to disease-producing microbes. A Other factors such as soil pH and tionship with plant roots is probably closer look at plant-soil relationships nutrient availability are also of critical the most important in terms of plant reveals that soil microbes are an impor- importance but most nutritional prob- establishment and survival. The fact tant factor in the success and failure of lems can be largely overcome by soil that nearly half of plant mass is root plant populations. fertilizer use. Re-establishing native material indicates soil factors are of South Texas native plants exhibit plant populations may also involve prime importance to plant develop- a range of “preferences” for growth. re-establishing native soil microbial ment. Many microbes can colonize If we can agree that chief among these populations, or at least, improving the plant roots, which can result in either is tolerance to heat and dry soil, we soil to boost microbial growth around beneficial or detrimental outcomes. can look to other factors for help with developing plant roots. How can we Most often, however, microbes pro- re-vegetation problems. Soil type is do this? mote plant growth. They aid the plant one such factor. Plants such as bundle- It is reasonable to assume that by improving access to nutrients, i.e., flower (Desmanthus sp.) appear to do as native plants are lost, populations mycorrhizal fungi increase the absorb- best on clay soils, while wooly croton of their specific beneficial rhizo- ing area of roots for nutrient and water (Croton capitatus) is more common sphere microbes become decimated. uptake. One little-known aspect of on sandy soils. Another croton (one- ­Replacing those native soil microbial

 What’s in a Name?

By Forrest Smith, STN Collections and Evaluations Manager

South Texas Natives (STN), the USDA-NRCS E. “Kika” de la Garza Plant Materials Center, and the Texas Agricultural Experiment Station are pleased to announce 7 new native plant germplasm releases in 2006. These include ‘La Salle’ Arizona cottontop, ‘Dilley’ slender grama, ‘Atascosa’ Texas grama, ‘Chaparral’ hairy grama, ‘Catarina’ plains bristlegrass, ‘Mariah’ hooded windmillgrass, and ‘Welder’ shortspike windmillgrass. Development of each germplasm © Larry Zibilske release begins by collecting seed of a Legumes can take care of their nitrogen needs by producing root nodules species from its native field environ- containing nitrogen-fixing bacteria. ment. The number of field collections varies by species according to the populations may not be easy. But, it from agriculture. In that environment, native distribution but is commonly is realistic to expect that it would be soil microbes are intentionally applied 10–50 collections for a single species. beneficial to replace lost native soil to soil or plants to assist in nutrient When an adequate number of collec- microbes with microbes that have been acquisition or to protect the plant tions (or accessions) are obtained, the shown to aid plant growth. Seed coat- against some pathogen. Most of this initial evaluation begins. Evaluation ing may be a viable way to inoculate is practiced on organic farms. Since plots are planted at various locations native plants with beneficial microbes. organic farmers try to mimic natural in the region. After 2–3 years of eval- This ensures the presence of beneficial ecosystems, parallels between organic uation, superior collections are identi- microbes as the plant roots take hold in farming and natural systems are abun- fied for seed increase and release, then the soil. Coating or pelleting seed can dant. Organic farmers pay much atten- distributed to commercial producers. also be used to provide trace elements tion to the soil. They realize that soil Most of our germplasm releases and other needed growth factors that physical properties, soil fertility, and are made up of several accessions of promote seedling vigor. soil biology determine how productive each species. However, hooded wind- Almost all of our understanding their plants will be. What they do in millgrass and shortspike windmillgrass of plant-microbe interactions comes promoting soil health and plant vigor exhibit unique growth forms, making in agricultural systems should also them valuable for use in right-of-way South Texas Natives is provide useful guidance and concepts stabilization efforts. Consequently, pleased to announce that for native plant re-vegetation efforts. they will be initially released as single the Texas Department Using what we know from agricul- lines. All of the releases are comprised tural systems may give us a leg-up on of material that is adapted to multiple of Transportation has addressing the frustrating problems in range sites, various soil types, and the renewed our grant in the ­re-establishing native plant populations broad range of climatic conditions amount of $150,000 a year in South Texas. found in South Texas. for 5 years to continue our Each germplasm has been assigned pursuit of releasing quality an exclusive name. These names will Dr. Larry Zibilske is a Research Soil native plant seeds for use Microbiologist for the USDA-ARS Integrated provide seed dealers and consumers Farming & Natural Resources Research Unit with a unique way to identify releases along highways. in Weslaco. He also serves on the South Texas Natives Technical Committee. made by STN and our cooperators.

 When choosing a name for our Large Seed Increases the aid of Speedling’s sophisticated releases, one component of the name greenhouses and seed sowing equip- represents a county name, soil type, By Forrest Smith ment, STN can have large quantities or area of collection. For example, 4 of transplants grown for seed increase of the 12 accessions released as part A necessity of releasing a germ- fields. Transplanting greenhouse- of ‘La Salle’ Arizona cottontop origi- plasm of any plant is to have adequate grown seedlings is the most reliable nate from La Salle County, TX. The quantities of seed available for com- method of increasing small quanti- goal of each release name is to make mercial growers. Seed quantities of ties of seed from our native plant them identifiable to South Texans many of our original collections are ­accessions. Speedling’s technology and unique to South Texas. Future very small, and the seed collected allows STN to maximize the number releases developed by STN will be from evaluation sites cannot be used of plants we can produce from a given named similarly. for seed increase (that is, seed pro- amount of seed. Transplant fields can Each release will be tagged with duction) because of possible cross be kept much cleaner than seeded a Texas Department of Agriculture pollination. Our limited greenhouse fields by applying pre-emergent- her green seed tag containing the South space is utilized primarily for grow- bicides that will not harm transplants Texas Natives logo. When buying ing transplants for evaluation plots, while preventing germination of weed native seed for your next South Texas which are much smaller than a seed seeds. The transplant fields are rigor- project, ask specifically for these increase field. For example, to plant ously cleaned and inspected for weeds releases. Only seed sold by the germ- a replicated evaluation field plot, only because the harvested seed needs to be plasm name, tagged with a green seed 20 transplants of each accession (or extremely pure. The seed produced tag bearing the STN logo, and certified collection) are needed. However, to from these increases is the final prod- as “selected/tested” seed is produced plant a seed increase field, we need uct we release to seed dealers and con- and adapted for use in South Texas. 10,000 transplants of each acces- sumers for commercial production. Whenever possible, these releases sion! Since STN does not have the ­Additionally, we utilize this same pure should be planted as part of a mix- space to grow the large quantities of seed in our establishment experiments. ture of native species to maximize the transplants required for seed increase This past spring, STN and our coop- diversity of the restoration planting. fields, Speedling, Inc. in Alamo, TX, erators transplanted approximately As we release more species, a mixture provides this service for STN. 200,000 seedlings to produce seed of of forbs and grasses will be available Speedling, Inc. is a world renowned several selected native species for sub- representing the various vegetation grower of vegetable transplants. With sequent germplasm releases. types in our region. Several other species are cur- rently under evaluation for release in upcoming years. In 2007, look for germplasm releases of pink pap- pusgrass, whiplash pappusgrass, slim tridens, sideoats grama, brownseed paspalum, crinkleawn, orange zexme- nia, and clammy weed. In 2008, look for yellow Indiangrass, little bluestem, big bluestem, seacoast bluestem, silver bluestem, four-flower trichloris, awn- less bush sunflower, bundle flower, wooly croton, partridge pea, and Texasgrass. And, there’s more yet to come! We are currently evaluating the potential of many other native plants for future release. © Forrest Smith Several hundred 200-plug trays of grass seedlings approaching readiness for transplanting.

 years of experience in the commer- cial nursery and landscape industry. Stephanie’s experience with APHIS primarily involved the collection and identification of plant pests, including insects, diseases, and noxious weed seeds as well as regulation of imported plant and animal products. Her work with STN will focus primarily on col- lection, identification, and control of pests that interfere with native plant and seed production. She will also catalog the beneficial insects that live on native plants and those insects that provide a tasty meal to insectivorous wildlife. Stephanie is married to Dr. Tyler Campbell, who is the field station leader for the USDA National Wild-

© Forrest Smith life Research Center Texas Field Sta- tion, which is located at Texas A&M Planting a seed increase field at Bladerunner Farms, Inc., in Poteet, TX. ­University-Kingsville. Stephanie and Tyler have a 3-year-old son Wesley Seed Increase Growers not progress with the development of and a 1-year-old daughter, Morgan. In 2006, Bladerunner Farms and native seed without the valuable assis- Robin Harkey joined STN in Rio Farms will be growing our seed tance from our cooperators. December 2005. She oversees the increases. Bladerunner Farms, near greenhouse operations and seed test- Poteet, is one of the largest commer- ing for STN. Robin’s role focuses cial turf grass growers in South Texas. STN Welcomes 2 New on propagating plants for field evalu- They will be growing increases of Research Associates ations and seed increases. She also hairy, slender, and Texas gramas. Rio heads seed germination testing and Farms, near Monte Alto, is a large By Forrest Smith will work to optimize growing prac- research farming operation. They tices in both the greenhouse and the will be growing increases of yellow South Texas Natives recently hired Indiangrass, Arizona cottontop, little 2 new part-time research associates— bluestem, big bluestem, hooded wind- both bringing much needed knowledge millgrass, shortspike windmillgrass, and experience to the program. Our and sideoats grama. Previously, the new employees will focus on 2 major plains bristlegrass increase field was facets of the project: greenhouse man- planted in 2005 at the Texas Agricul- agement and pest management. tural Experiment Station in Beeville. Stephanie Campbell joined STN Our cooperators play an essential in January 2006 and is initiating a pest role supporting our efforts in reach- management program for STN. She ing our goal of releasing quality received her bachelor’s and master’s native germplasm to the public. South degrees in plant and soil science from Texas Natives in conjunction with the Texas A&M University-Kingsville. Texas Foundation Seed Service over- Stephanie recently worked as a Plant sees distribution of the seed from the Protection and Quarantine Officer for increases. Ownership of the seed is the USDA Animal and Plant Health © Forrest Smith retained by STN until final release to Inspection Service (APHIS) in Atlanta, STN research associates Stephanie commercial seed producers. We could GA. Additionally, she has several Campbell (left) and Robin Harkey.

 TAES Uvalde, TAES Dallas, Corpus bunchgrass considered one of the “big Upcoming Releases by South Texas Natives Christi Botanical Gardens, San Anto- 4” prairie grasses of the true prairie nio Botanical Gardens, and the World associations in North America. Arizona cottontop Birding Center in Mission to grow Slender grama as ornamentals in landscapes. These Seacoast bluestem (Schizachyrium Texas grama plants include the following: scoparium var. littoralis) is a peren- Hairy grama nial bunchgrass native to coastal Plains bristlegrass Clammyweed (Polanisia dodecandra regions throughout North America. Hooded windmillgrass ssp. riograndensis) is an annual forb Shortspike windmillgrass with bright pink flowers attracting but- Indian blanket (Gallardia pulchella), terflies, bees, and other pollinators. or firewheel, is an annual or weak seed testing laboratory. Robin earned 2 perennial found in sandy areas grow- bachelor’s degrees, one in horticulture Arizona cottontop (Digitaria califor- ing to 2 feet tall. from Texas A&M University and one nica) is a perennial grass with ‘cottony’ in biology from Southwest Texas State seedheads and pubescent leaves. Perennial lazy daisy (Aphanoste- University. She previously worked 5 phus riddellii) grows 9–12 inches tall years as a greenhouse research associ- Big bluestem (Andropogon gerardii and has yellow-disked, white-rayed ate on the development of transgenic var. gerardii) is a robust perennial flowers that bloom from February to corn with ProdiGene®, a biotechnol- bunchgrass considered one of the “big ­December. ogy company in College Station. Her 4” native grasses of the true prairies of experience with ProdiGene® primar- North America. Eastern gamagrass (Tripsacum dac- ily involved greenhouse management, tyloides) is a clump-forming rhizoma- research, and writing of standard Sideoats grama (Bouteloua curti- tous perennial grass that grows 5–10 operating methods and procedures for pendula var. curtipendula), the State inches tall. greenhouse protocols. Robin has also grass of Texas, is a perennial bunch- enjoyed experiences in other plant grass that grows 2–3 feet tall. Two-flowered trichlorisChloris ( research including peas and potatoes, crinita), or sometimes called false and commercial horticultural and Yellow Indiangrass (Sorghastrum Rhodesgrass, is a warm-season peren- botanical garden environments. She nutans) is a perennial, rhizomatous nial bunchgrass. and her husband Dr. Justin Harkey, a local veterinarian, have a 2-year-old daughter, Morgan. Please welcome these new assets to STN!

Plants Selected for Horticultural Evaluation 2006

By Paula Maywald, STN Coordinator

While evaluating native plants for seed production, it’s hard not to notice when a plant has attractive foliage or beautiful flowers. Since very few of the native species we grow are avail- able as ornamentals, we are growing several of them to be evaluated for their potential to be released as hor- © Shelly Maher ticultural selections by commercial nurseries. Plants have been sent to Perennial lazy daisy is one of the plants selected for horticultural evaluation.  Plant Profile P. vaginatum), trichloris (Trichloris Arizona cottontop has been shown Arizona cottontop criniata, T. pluriflora), windmillgrasses to have very high potential for use in (Digitaria californica) (Chloris cucullata, C. subdolicho- rangeland revegetation in Arizona, and stachya), and slim tridens (Tridens the Sonoran and Chihuahuan deserts By Forrest Smith muticus var. muticus, T. congestus). (Cox et al. 1982, USDA et al. 1999). ­Arizona cottontop is somewhat shade These traits make Arizona cottontop Arizona cottontop (also known as tolerant and frequently grows within an ideal species to use when attempt- California cottontop) is a warm season, the canopy of shrubby plants such as ing to restore or revegetate rangelands perennial grass native to South Texas. hog plum (Columbrina texana), gran- in South Texas. However, until now, Arizona cottontop is found in much of jeno (Celtis pallida), shrubby blue sage no regionally adapted, commercially the southwest, ranging from Colorado, (Salvia ballotaeflora), and guaycan available seed stock has been available through New Mexico and Arizona, (Porlieria angustifolia). for purchase or use in South Texas. Oklahoma, most of Texas and south Arizona cottontop provides good South Texas Natives began obtain- into the northern portions of Mexico. It forage for livestock and fair forage ing Arizona cottontop collections in is most common in the central and west- for wildlife (Gould 1975). It is highly 2001. Above average rainfall across ern portions of South Texas. Within palatable (Bedunah and Sosbee 1984) most of South Texas in the summers these areas it is found on sandy loam, and is preferred over most other native of 2002 and 2003 provided ideal con- loam, gravelly loam, clay, and clay forage species during all seasons of ditions for wild seed production of loam soils. In South Texas, Arizona the year by domestic livestock (Cable Arizona cottontop. We were able to cottontop is usually found growing in 1979). The upright, bunchgrass growth obtain 54 collections (accessions), 31 relatively undisturbed prairies or well- form of Arizona cottontop makes it an of which were chosen (based on dis- managed prairies and in brushlands, ideal species to use when attempting to tribution of the collections) for evalu- on good and excellent condition range increase nesting cover for ground nest- ation, selection, and potential release. sites. It frequently grows in association ing birds such as bobwhite quail. Many The evaluation of these 31 accessions with other perennial native grasses such species of wildlife (mammals, reptiles, of Arizona cottontop took place for as bristlegrasses (Setaria leucopila, S. and insects) benefit from the rapid 2 years at Rancho Blanco (Laredo, vulpiseta), gramas (Bouteloua spp.), production of seed and vegetative bio- TX), Rio Farms (near Monte Alto, pappusgrasses (Pappophorum bicolor, mass following rainfall in South Texas. TX), Texas Agricultural Experiment ­Station-Uvalde, and the USDA-NRCS E. “Kika” de la Garza Plant Materi- als Center in Kingsville. Seedlings of each accession were grown and planted in replicated field plots at each location in the spring of 2004. Each plot was evaluated bi-monthly in 2004 (irrigated) and monthly in 2005 (non- irrigated). The seed was collected from each accession when ripe and tested for germination each year. During the course of evaluation, we gained a great deal of knowledge about the life history and characteristics of Arizona cottontop in South Texas that further supported its use in rangeland restoration. We tested multiple accessions of Arizona cottontop over a 2-year period at multiple sites. We observed © Forrest Smith extremely high active seed germina- Arizona cottontop’s velvety white panicle grows 2–5” long. The seed is a food tion, averaging 60.9%. Furthermore, source to mammals, reptiles, and insects. 93% of seeds germinated on days

 Salle’ germplasm Arizona cottontop. These accessions had an average ger- mination of 62.7% over a 2-year period at all sites combined. Accessions were selected based on evaluation perfor- mance (plant vigor, seed production, forage production, etc.) and active seed germination. The accessions represent- ing this release originate from 9 South Texas counties, with differing soil types, climates, and range sites. Arizona cottontop seed is fuzzy and lightweight. Consequently, the seed will likely require coating to facilitate planting with seed drills and conventional broadcasting equipment. Without coating or use of a carrier, it is difficult to obtain uniform planting distribution. For pure stands, Arizona © Forrest Smith cottontop should be seeded at a rate of Arizona cottontop in a field plot. 1–2 pounds pure live seed (PLS) per acre. When used in combination with 3–5 after initiation of favorable condi- summer, if adequate soil moisture is other species, seeding rates should be tions. High active seed germination, present. Seed production during June– adjusted according to the percentage of combined with the quick germination July 2005 at Rancho Blanco was 142 Arizona cottontop desired at the site. response of Arizona cottontop, means lbs/acre with excellent seed quality. Arizona cottontop can be planted across that this species is able to establish Following our evaluations in 2004 most of South Texas in sandy loam, itself very quickly—an important trait and 2005, 12 accessions of Arizona cot- clay, clay loam, loam, and gravelly in South Texas—where we know how tontop were selected for release as ‘La loam soils. Arizona cottontop is rarely fast things can dry up! Most species that possess these traits are annuals, but Arizona cottontop is strongly perennial, and the plants in our research plots have shown excellent survival (near 100%) during 2 years of observation; one of those years was without irrigation. Studies in Arizona have shown that individual plants may live as long as 15 years, even when grazed (Cable 1979). Plants respond to adverse conditions (e.g., drought, extreme temperatures) by going into dormancy. However, upon the return of favorable conditions (like rainfall) they can produce forage and seed extremely fast. At Rancho Blanco, we observed Arizona cottontop go from being completely dormant to having ripe seed in just 20 days! Our data show that plants will produce seed © Forrest Smith year-round, even during the heat of the Arizona cottontop occurring within a stand of bufflegrass.

 found in deep sandy soils of South Two accessions of Arizona cotton- Range Mange. 37(6):483–487. Texas, and it is not recommended for top are being evaluated for horticultural Cable, D. R. 1979. Ecology of Arizona such areas. Newly seeded areas should use as well. These accessions exhibit a Cottontop. Res. Pap. Rm-209, be deferred from grazing for 1–2 grow- blue-green color and are covered with USDA For. Ser. Rocky Mtn. For. ing seasons to ensure establishment pubescent hairs, making them an attrac- and Range Exp. Stn., Fort Collins, of seedlings. Dates for planting vary tive ornamental. These accessions are CO. 21 p. according to rainfall in South Texas, but currently under evaluation at several Cox, J. R., H. L. Morton, and T. N. generally late summer to fall, or spring locations in South Texas to determine Johnston, Jr. 1982. Vegetation plantings are best. Arizona cottontop their suitability for landscape use. Restoration in the Chihuahuan and seedlings have been observed emerg- Seed of the 12 accessions compris- Sonoran Deserts of North America. ing most frequently in late summer ing ‘La Salle’ germplasm Arizona cot- Agricultural Reviews and Manuals at our evaluation locations. The seed tontop is currently being produced in ARM-W-28. Washington, D.C.: should be planted no deeper than a ¼ seed increase fields at Rio Farms near USDA Ag. Res. Serv. 37 p. inch. Some seedbed preparation (light Monte Alto, TX. Foundation seed (seed Gould, F. W. 1975. The Grasses of disking) is recommended before inter- used to establish commercial produc- Texas. Texas A&M University seeding in established vegetation. tion fields) will be released to com- Press. College Station, TX. It appears that Arizona cottontop mercial growers this fall. We anticipate USDA, NRCS, AAE, ARS. 1999. is a good choice for reseeding highly commercial seed production to begin Notice of Naming and Release disturbed sites, such as pipeline right- before the spring of 2007. of ‘Loetta’ Arizona Cottontop of-ways or recent brush control proj- For help with planting recommen- ­(Digitaria californica). NRCS, ects. Its rapid germination and growth dations, seeding mixtures, or to report Washington, D.C. provide quick cover and may help your results with ‘La Salle’ germplasm prevent soil erosion. Additionally, Arizona cottontop, please contact it can be inter-seeded into existing ­Forrest Smith, STN Collections and vegetation to help increase species Evaluations Manager, at email address diversity or forage production. In fact, [email protected]. ­Arizona cottontop has been observed spreading into established stands of References bufflegrass (Pennisetum ciliare) at our Bedunah, D. J., and D. J. Sosebee. Rancho Blanco evaluation plots and 1984. Forage response of a mes- fallow cropland at TAES-Uvalde and quite-buffalograss community Rio Farms. following range rehabilitation. J.

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