Wildflower is published quarterly by the Wildflower Center. Its content is national in scope with articles about the conservation and use of native plants as well as news from the Wildflower Center. A subscription is provided to Wildflower Center members as a benefit of membership.
The Native Truth by Sheryl Devore - Fall 2004
Once upon a time, a gardener spotted some horsetail (Equisetum sp.) for sale and decided to purchase it for her water garden, already brimming with other plants. The best thing, she thought, was that the horsetail was native to her region. Planting with natives is easy, costs less, and is better for the environment, the gardener reasoned. Within the next year the gardener noticed the horsetail taking over some of her other native water-loving plants - and she wondered if some of what she had learned about native plants was more fairy tale than fiction.
"There is a definite notion among some of the public that (merely by virtue of being indigenous) native plants are hardier, more drought-resistant, require less maintenance, and require fewer amendments such as soil and fertilizer than plants that are not native," says Steve Windhager, director of Landscape Restoration for the Lady Bird Johnson Wildflower Center. Windhager also has heard a contrasting view - especially from some land managers - that native plants are too hard to grow and too difficult to maintain.
Windhager says that actually both can be true, depending on the circumstances.
Below we examine six commonly held beliefs about native plants. In doing so, we hope to separate fact from fiction regarding their natural beauty, environmental necessity, and economic value.
No. 1 - Natives are harder to find and cost more. In general, this is not true. Native vegetation can be more costly and difficult to find than some non-natives that have become staples in gardens and on roadsides over the years. Obtaining large quantities of native plants for roadside vegetation is difficult and costly as well. In Montana, native plant industry suppliers of seeds, plants, and other forms of regional vegetation have experienced a volatile rise and fall in the demand for and cost of growing, obtaining, and selling their products.
Overall, however, finding plants native to a particular region for both large land managers and the local gardener has become easier and less costly, and it should continue to improve. Today, home gardeners can attend native plant sales at nearby forest preserves and botanical gardens, with seeds and plants coming right from the region.
And consider this: Land managers and gardeners who plant invasive, non-native plants could contribute to a major, costly national problem: that of eliminating invasive plants and animals. By planting alien plants in their yards, gardeners encourage them to be spread by the wind and by animals that carry the seeds to be planted in other landscapes.
According to a 2000 report in the peer-reviewed BioScience magazine, non-native species, including both plants and animals, may be responsible for an economic loss of $137 billion annually in the United States.
Also consider that landscaping with non-natives can be just as expensive as landscaping with natives. Craig Dremann, owner of the California ecological restoration firm Reveg Edge Services, says his state's highway department spends $1 million per mile each year to landscape the state's roadways with non-native plants. This summer the state experienced a drought, demanding the highway department spend even more money irrigating the roadway plants. Dremann says in the long run California would spend less planting drought-resistant native grasses along highways.
No. 2 - Native plants always require less work and maintenance and help conserve resources. This is not always true, but it helps to put the right native plant in the right place.
"One misleading assumption about native plants, however, is that because they belong here they can magically grow with minimum input and preparation," says Dr. Mark Simmons, restoration ecologist at the Wildflower Center. "Throwing handfuls of native wildflower seed into an abandoned, weedy part of your yard is probably going to be as successful as doing the same with non-native seed."
He adds that the removal of existing plants, soil preparation, and supplemental watering during establishment are equally vital to native or non-native plantings. In addition, if natives are put in the wrong place - for example, horsetail in a dry environment - their survival may demand a lot of resources. He and Windhager agree that putting the right native in the right place - with proper soil, moisture, and light - will reduce or eliminate the need to water, fertilize, or spray with insecticides and pesticides.
When gardeners and land managers introduce a plant to a landscape, adding water will help ensure the plant survives and gets established. Windhager says those who introduce a young plant (4-inch pot rather than a 1-gallon pot), and put it in the right place, may never have to do anything to that plant again. But those who plant a larger specimen plant or want one to bloom faster and grow more quickly may need to add additional water and fertilizer.
Even after a plant is established, land managers and gardeners will have some work to do contending with the exotic species growing nearby. The home gardener may need to periodically remove encroaching invasive plants. For example, garlic mustard (Alliaria petiolata) and buckthorn (Rhamnus cathartica), two European plants that have harmed native Midwestern woodlands, can also appear in backyards and need to be removed so that they don't take over the natives.
Laurel Ann Kaiser, a gardener from Hawthorn Woods, Illinois, and her husband, Jim, meticulously remove the buckthorn from their yards to encourage native wildflowers such as Solomon's seal and Jack-in-the-pulpit as well as shrubs like witch hazel to grow in their oak woodlands. But one day, the Kaisers noticed garlic mustard creeping into their yard. So now they have to work to keep that under control. "The trouble is," says Laurel Ann Kaiser, "our neighbors don't remove the buckthorn and garlic mustard in their yards, so we'll probably be removing the non-natives forever."
Gardeners and land managers working with large meadows and prairie landscapes also need to perform periodic land management to keep the natives healthy and thriving. "In Texas, wildflower meadows (which typically feature annual spring flowers) require management. For example, prescribed fires or timed mowing and grazing can help keep grasses and other perennial species from taking over," Windhager says.
In Hawaii, land managers must erect fences around restored landscapes to keep out wild non-native animals that eat the vegetation. In addition, staff of a land management partnership in Hawaii working to protect such plants as alani (Melicope ovalis) at Haleakala National Park must regularly inspect and maintain the fencing.
To successfully grow native plants, then, can in some cases take just as much knowledge and care as non-natives, says Simmons.
No. 3 - Native plants are never invasive. Native plants can be invasive when growing in an altered environment - and unfortunately human activities have created environments ripe for some natives to take over. For example, in Texas the native blueberry juniper or mountain cedar (Juniperus ashei) is becoming invasive.
This species evolved in and around the grasslands of central Texas where periodic fires swept through the region. Most native trees growing in this environment re-sprout after a fire, but this particular juniper does not. Instead it creates abundant fruit, eaten by birds which then "plant" the seeds to propagate the species. Periodic fires have historically kept the spread of this species in check.
"But when we began to control wildfires and, with the advent of barbed wire, began to see overgrazing of the grasses in central Texas, juniper populations exploded, often creating thickets where before the system was likely to be open savanna," says Windhager.
In gardens, natives can also become invasive. Windhager cited one example: tall horsetail (Equisetum hyemale). The species was historically confined to river channels, where it was often kept in check by periodic flooding. However, put it in a water garden at home and it could take over if you don't watch it carefully, something the gardener in our fairy tale didn't know.