Purple coneflower with mealy blue sage and brown-eyed Susan

Photography credits are available here

Copyright © 2025 by Andrea DeLong-Amaya and the Lady Bird Johnson Wildflower Center. All rights reserved.

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ISBN 978-1-64326-110-2

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Large Buttercup and friends

Sensitive briar (Mimosa roemeriana), drummond phlox (Phlox drummondii), lace cactus (Echinocereus reichenbachii), Spanish dagger (Yucca treculeana), yellow passionflower (Passiflora lutea), cenizo (Leucophyllum frutescens)

Gayfeather seed stalks hold court well into fall

Preface

My hope for what lies ahead in the field of landscape design . . . is not a revolution against the use of non-natives, but a resolution to educate ourselves about what has worked for Mother Nature through the ebb and flow of time and to put that knowledge to work in the planned landscapes that are everywhere a part of our lives.

—Lady Bird Johnson

Like so many of us who were lucky enough to be nannied by the great outdoors, I felt a deep belonging and centeredness in the rural Michigan woods surrounding the trailer park where I spent the summers of my early years. Here began my connection with the natural world, observing a walkingstick insect surveying a maple tree trunk, collecting a rainbow of leaves from those same maples come fall, pushing a finger into the earth-scented, spongy moist moss that our neighbors complained about invading their lawn, and eating huckleberry pie baked by my dad from fruits the neighborhood kids and I so proudly and competitively foraged. My father introduced me to my first wildflower guide. I was astonished that there were such things as wild onions and that you could eat them (even though I didn’t particularly like the endless aftertaste!).

Wildflower Center founders Helen Hayes and Lady Bird Johnson

Wetland Pond at the Wildflower Center

Moving to Austin shifted my seven-year-old understanding of nature from the soft and gentle Michigan summers (let’s ignore the winters for now) to the staggering brutality of Texas heat. It is understandable how newcomers find themselves flummoxed facing a nightmare of writhing bugs, uncooperative soils, and capricious weather. Coddling plants from far-flung lands often results in disappointment and wasted resources. Gardening here can seem hopeless.

But, just as plunges into Austin’s bracing Barton Springs pool, glorious summer thunderstorms, and winter days often balmy enough to be enjoyed in shorts adjusted my attitude with time, gardeners, too, may find rich rewards by embracing the embodied wisdom that native plants have accumulated through millennia, sculpted by the victories of rolled-up-sleeve evolutionary rumbles. Our home team flora are best equipped to endure the extremes they face. After all, they grow and thrive here naturally without our assistance.

Lady Bird Johnson

The deep respect, appreciation, and awe for the natural world that consumed me as a child continues to grow with me. It is what led me to the important work and mission of the Lady Bird Johnson Wildflower Center where I first became a member, then shortly thereafter fortuitously joined the staff ranks as a gardener in 1998 (I don’t understand the math here . . . I guess I must have been twelve years old when I started!).

The organization, a signature piece of Lady Bird Johnson’s environmental legacy, was founded by Mrs. Johnson and Helen Hayes. Dedicated on December 22, 1982, on Mrs. Johnson’s seventieth birthday as the National Wildflower Research Center, it was renamed as the Lady Bird Johnson Wildflower Center in 1997 in her honor. From the beginning, Mrs. Johnson was ahead of her time in understanding and promoting native plants as an important effort in support of the natural environment as well as for human welfare.

Having matured from our humble east Austin site to the 284 acres we currently steward in south Austin, we are now an Organized Research Unit of the University of Texas at Austin, where our values of ecological resiliency drive our mission of inspiring the conservation of native plants. We practice this through internationally recognized Texas native-plant gardens, regenerative landscape stewardship, plant conservation, education and outreach programs, and research.

Skeletonized prickly pear with aster

What Is a Native Plant?

Periodically the question arises regarding how long a plant needs to be in a location before it is considered native or indigenous. “I have 100-year-old roses from my great-grandfather, do they count?” Bluntly: no. Even though we freely throw around the phrase “native plants,” the concept is complex and often muddied. In shorthand, we could claim them to be plants that occur naturally where they evolved without human introduction.

Your great-grandfather’s roses may be well adapted and flourishing, but they were brought in by human hands, and their relatively short tenure here pales compared to the hundreds or thousands of years it takes for significant (observable) evolution to occur. However, given that genetics change with every generation, imprecision plagues our definition. Stating a minimal duration for a plant to be legitimately native to a place feels arbitrary, but prior to European colonization—beginning in earnest around the early 1600s—marks a commonly cited timeframe for the United States, after which begins a period of previously unmatched speed and volume of new plant introductions from across the Atlantic.

Even within that framework, a gray area exists because early Indigenous peoples are known to have moved plants back and forth throughout Mexico, the US Southwest, and beyond.

The semicultivated devil’s claw was used for textiles and food by practically every tribe in these areas, Agave americana has been the raw base for mezcal making, and chile pequin has been widely used as seasoning. The products from these plants were so important that people brought propagules along when they traveled from one community to the next. Most of us broadly embrace these species as native where they occur, even though these earliest settlers are likely responsible for their placement.

People have been tinkering with plant genetics for millennia. Through generations of discerning collection and planting, the devil’s claw mentioned above was selected for longer claws best suited for basketry. Most of the peppers enjoyed in our modern diets derive from our native Capsicum annuum, including jalapeños, serranos, and bell peppers. These are known as cultigens or cultivars, deliberately bred by cross-pollinating parents with desirable traits to create offspring with enhanced features based on the interest of the hybridizer. Other variations originate as naturally occurring mutations, referred to as sports (a rare flower color, for example), and some breeders induce mutations with radiation or chemical treatments. Vegetative propagation ensures clones with persistent desirable traits, while seeds, by nature of cross-pollination, embody genetic diversity. Cultigens and cultivars grown from seed usually revert to parental traits eventually, though sometimes completely new expressions arise.

Controversy swirls around the idea of using cultigens and cultivars of native plants. Should they be considered native? Do they provide enriched or degraded habitat value compared to pure natives? Perhaps it’s better to use a native cultivar (nativar) instead of a common exotic plant to take advantage of drought resistance and other benefits of natives. Or maybe the altered genetics of a nativar presents a contamination risk to nearby native plant populations. Genetic diversity makes populations more resilient, but would a few cultivated nativars in residential-scaled gardens make a significant negative impact?

I certainly don’t have all of the answers, and studies indicate that results vary from species to species or cultigen to cultigen. More research is needed. Decision-making parallels that of natives versus non-natives, and depends on your objectives. A restoration project most certainly calls for the use of pure natives, avoiding manipulated traits and ideally opting for a local genetic source. On the other hand, simply propagating from an unusual but naturally found white-flowered spiderwort would likely have vanishingly negligible detrimental effects, if any.

Geography

Another critical aspect of the definition relates to geography. Native to where? Texas? North America? The planet Earth? You get to decide how narrowly to define the parameters for your gardening project. Your motivations will help you conclude if you want to use natives exclusively, predominantly, or as supplements in your landscape.

An ecological restoration calls for local provenance and represents the purest interpretation of the idea. On the other hand, if conserving water drives your plant selection, you might decide to broaden your choices and use water-thrifty plants from outside of your local region. However, Texas’s vastness and varied weather, hydrology, and soil extremes create environments influencing plant ranges. Maximize your chances of success by taking extra care when selecting species from other parts of the state. You wouldn’t plant a southern magnolia from east Texas in Big Bend, would you? A Mexican olive smiles at guests touring the San Antonio Botanical Garden, but in Waxahachie, it quickly succumbs to Jack Frost’s sharp bite. Just because a plant hails from Texas doesn’t mean it lives happily anywhere in the state. Generally speaking, the closer to its home range, the better.

Adapted, Naturalized, and Invasive Plants

As we contemplate the question of what is a native plant, an examination of what isn’t native facilitates the conversation. Common ornamentals mistaken for Texas natives—such as pink skullcap (Scutellaria suffrutescens), ‘Indigo Spires’ sage (Salvia longispicata ×farinacea ‘Indigo Spires’), and ‘New Gold’ lantana (Lantana camara ‘New Gold’)—actually originate in Mexico and other countries, or may be new to nature as human-invented cultivars. Although from outside of the United States, plants from nearby Mexico, of course, likely fit more appropriately in a Texas garden than a variety from distant Maine but nonetheless are not native to Texas. Frequently found in water-thrifty landscapes, these introduced examples include plants that are well adapted to our climate and soils. As long as they remain well-behaved and not invasive—defined as proliferating excessively outside of cultivation—they add options.

Early in my studies as a naturalist, I erroneously assumed that, because they sprouted in wild areas, plants such as heavenly bamboo (Nandina domestica) and Chinese tallow trees (Sapium sebiferum) were indigenous. Only later would I recognize their introduced and invasive status. Synonyms describing species not native to a location where they are found include non-native, exotic, introduced, or alien. Plants from Asia are introduced to North America. Plants from North America are exotic in Australia. Although the term alien is generally accepted, I prefer to avoid it due to its association with human noncitizen residents or little green people from galaxies far, far away.

Non-native escapees can be minimally problematic or very harmful. For example, annual henbit (Lamium amplexicaule) invades crop fields and other disturbed land but is too weak to displace established vegetation. Exotic garden plants or crops that remain after their caretakers have departed but fail to increase noxiously fall into the persistent or naturalized category. These remnants generally pose little to no harm, but if they thrive beyond our control we consider them invasive.

Gardeners curse plants as invasive when the plants betray their trust by heavily seeding out or running amok in their beds. Put into perspective, invasive under cultivation (i.e., with altered soils, supplemental water, and other protections from the elements) means something fairly different from invasive on an ecological scale. One poses a nuisance (albeit not insignificant), the other results in potential species extinctions. According to the Presidential Executive Order 13112, issued in February 1999, invasive species cause “economic or environmental harm or harm to human health.” Of course, not all introduced plants become overly aggressive or even naturalized. And regardless of how long it has been here, a naturalized plant, by definition, does not become native.

Indigenous peoples historically moved plants around intermittently over long periods of time. Settlers from east of the Atlantic, on the other hand, brought their familiar ornamental and food crops to the New World at historically unprecedented rates and quantities, too fast for many indigenous species to effectively adapt and literally hold their ground. What’s more, these imports arrived at their new digs without their associated predators and pathogens from their homelands to keep them in check. These novel colonizing plants displaced, and continue to displace, the original species, inflicting havoc on interdependent native organisms. We think of invasive plants as thugs, but it’s not their fault. They merely take advantage of the opportunities we give to them.

Horticulturists sometimes discount the negative effects of non-native invasives, claiming that because they are additive, they actually increase biodiversity. While this may hold true in the short term, over time as the colony increases, they outcompete natives and diminish habitat for fauna from thrashers to thrushes. A cautionary tale from watching escaped pampas grass (Cortaderia selloana) over many years along a local highway in Austin demonstrates that a few plants here and there may seem benign, lying latent for many years, even decades, before the population explodes under favorable conditions, hogging territory away from beloved bluebonnets, little bluestem, and other natives. Sadly, botanical gardens, designers, home gardeners, and the horticulture profession in general have contributed a good percentage of pesky plants to our environment.

Prickly pear backed by the Wildflower Center’s Great Hall

Some discussions contend that non-invasive exotic species can and do play a beneficial role in landscapes and that their evaluation should emphasize ecological performance over place of origin. In theory this seems reasonable. However, we must put our hubris in check: We cannot sufficiently understand all of the complex and intertwining secrets of nature to fully determine a plant’s role in its community. For example, kudzu (Pueraria spp.) from Japan, initially featured at the 1876 Centennial Exposition in Philadelphia, was later used by land managers to halt soil erosion. It seemed like a good idea at the time, but eventually the plant earned the infamous reputation as “the plant that ate the South.”

If invasive plants don’t seem like that big of a deal, consider the impact of other invasive species such as imported fire ants that not only sting humans but existentially threaten Texas horned lizards, ground-nesting birds such as bobwhite quail, and other wildlife. Within fifty years after the arrival of the imported chestnut blight, the American chestnut was all but eliminated, resulting in a crash of the squirrel population and the extinction of seven moth species. The cascading impacts cut deeply. Invasive plants destroy living communities as effectively as other invasive organisms, even if we don’t recognize the damage as readily. We may not suffer the impact directly, but other living beings fundamentally feel the effects.

To be fair, we must acknowledge that even some natives can misbehave in disturbed environments or under unfortunate land management (such as excessive fire suppression or overgrazing). Since most livestock find prickly pears and mesquite unpalatable, those plants increase under intense grazing or browsing. In the postsettlement era, with the goal of protecting our homes and businesses, we’ve unintentionally quashed the fires that once limited the spread of Ashe juniper (Juniperus ashei), allowing it to become one of our most consequential native aggressors. Unlike introducing exotic invasives, planting aggressive or opportunistic natives in your managed landscape won’t contribute to their invasive nature since they’ve always been in the area. Whether or not they morph into bullies depends on how land is managed.

Climate Uncertainty

Huge question marks loom in our future regarding climate. As we witness milder winters and overall warming trends, our weather simultaneously dishes out more extreme and erratic events. Intense cold, heat, wind, drought, and floods shape natural distributions more than average weather patterns. Over the last several decades, plants including huisache, retama, Mexican olive, and others have slowly pushed their upper boundaries farther north, into higher and cooler elevations, or have been planted outside their normal ranges only to succumb to punishing and prolonged freezes such as those experienced in 2021 and 2023. As these climate events continue, we expect ranges to get pinched.

In response to climate change, ecologists contemplate plans for assisted migration. Since plants move too slowly on their own to find new potentially safe grounds, this somewhat untested strategy involves speeding up relocations by deliberately planting species into new projected ranges—assuming appropriate habitats still exist, and they may not.

Opposing views, often held by the very same supporters of assisted migration (demonstrating our lack of confidence on the topic), point out that relying on predicted average weather isn’t sufficient. We need to plan for the extremes, but is that even possible? Our best guesses may be wrong, leading to adverse genetic mixing of disparate populations, wasted valuable plant propagules, and diverted time better spent on more certain endeavors. And, of course, this prompts a philosophical discussion about the essential definition of “native.”

We can only touch on the topic here, and there is still so much we don’t know. Ecologists currently recommend selecting plants already exhibiting wide-ranging adaptability, while sadly recognizing that specialists will eventually be left behind.