is reduced to only a few individuals, the genetic diversity of the population also is reduced, and its ability to survive disease is compromised. Because of an illegal harvest, we may lose a wild plant population with the genes that code for a chemical that could be used to save thousands of lives, or for resistance to a plant disease that could save an agricultural industry.
Illegal harvesting also can impact entire natural communities. For example, several insect species depend upon wildflowers for food, mating sites and places to deposit their eggs. Doug LeDoux, a researcher at the University of Missouri, has discovered that several species of robber flies use coneflower heads as places to lay their eggs. The flies use the flowering heads of coneflowers for courtship rituals and rely on the pollen as a source of food. "Any insect species that needs coneflowers for mating or egg-laying could be harmed by their demise," says LeDoux.
Coneflowers are among the most sought after medicinal herbs, and Missouri is home to five species. Researchers at the University of Missouri School of Natural Resources are studying the feasibility of growing native medicinal plants commercially. The idea that only wild plants produce sufficient amounts of bio-active compounds is not substantiated scientifically.
Dr. Dean Gray and Dr. Gene Garret are studying whether coneflowers and St. Johns wort can be grown as economically viable crops. They are attempting to develop profitable growing techniques that will result in high-quality medicinal plant material in the hope that developing a market for cultivated medicinal plant products will relieve the pressure on wild populations.
Gray is experimenting to see how the timing of drought stress affects the concentration of bio-active compounds in the plants. "By finding the right time for inducing drought stress," he says, "we should be able to consistently produce plants with relatively high concentrations of specific bio-active compounds."
The good news is that plants are a renewable resource and can be conserved or restored through proper use, protection and wise management. For those who want to continue using remedies based on native medicinal plants, there are ways to reduce your impact on wild plant populations. The following suggestions amount to good medicine for Missouri's native medicinal plants:
- Consider the source. Use only products from sources labeled as cultivated.
- Tell someone. Inform the manager, salesperson or cashier that you will buy only products made from cultivated plant material and why.
- If you see someone you think may be collecting plants illegally on public or private land, do not approach them. Contact the Conservation Department or your local law enforcement agency. Give a description of the person and the vehicle, the license number and the date and time.
Grow your own. Buy plants or seeds of the species you use most and learn how to prepare and use them correctly.
Home Gardening With Native Plants
- Digging up plants for use in home gardens is another threat to wildflower populations in Missouri. In recent years, there has been an increased appreciation for the benefits of landscaping with native plants. Native plants are attracting more home gardeners because they are easy to grow, usually require less water and fertilizer and are often naturally disease-and pest-resistant.
- If you want to collect plant material from the wild for your home garden, collect only seeds. Collecting entire plants for transplanting to your home garden is often unsuccessful because wildflowers usually do not survive the shock of being transplanted. You will be much more successful and waste fewer plants by planting seeds.
- Collect seeds only from large populations of the species you are seeking. This helps maintain the genetic diversity of the original population. It is best to collect plant seeds from populations near your intended garden spot. Plants collected from local populations are better adapted to local soil and climate conditions and are more likely to thrive than plants collected from far away.
- Another reason to stick to local populations is to prevent the mixing of gene pools from widely separated populations, which tends to homogenize the overall genetic diversity of a species. Remember, collecting any part of any population of wild plants (including seeds) has an impact on that population.
- In response to an increased demand for native landscape plants, many garden centers, nurseries and seed companies now offer a wide variety of native plant material. Several companies in Missouri deal strictly in seeds and container-grown stock of Missouri native plants. A big advantage to buying from these sources is that you can often get material grown from seeds from populations near your home. And, if you buy container-grown plants, your transplanting success rate will be nearly 100 percent. Some nurseries even guarantee their container-grown plants.