There are a lot of gardeners interested in using native plants, and there are good reasons for doing so, said a University of Illinois Extension horticulture educator.
"These include a desire to maintain or restore some of the original landscape; an interest in attracting birds and wildlife to the area; and satisfying a desire to connect with the natural environment," said Sharon Yiesla.
"Some communities may even specify that only native plants can be planted. Incorporating native species into an existing environment can be easy. It is just a matter of knowing what each plant needs and of being able to meet those needs."
What exactly are native plants? They are often defined as plants recorded as growing wild in an area at the time scientific collection began in that area. Other plants are considered introduced.
From a more subjective viewpoint, gardeners need to consider what native means to them, she noted.
"Some people are satisfied as long as the plant is considered native to North America or the United States," she said. "Others may feel that they only want to use plants native to the state in which they live. Yet others may want plants to be native to their immediate area."
There are some misconceptions about native plants. It is often stated that native plants have fewer disease and insect problems. This is not necessarily true.
"Some native plants have few problems while others are constantly plagued," Yiesla said. "We have higher expectations in a managed landscape. A native plant suffering from a disease or insect in the woods may go unnoticed. The same plant in a traditional landscape may give a poor appearance.
"Another misconception is that native plants are adapted to this area so they will have superior growth. In terms of cold hardiness, this is true. However, when we look at soil conditions we see a different picture."
Many of the soils in our yards are disturbed; they may be primarily subsoil (which is inadequate for plant growth) or a subsoil/topsoil mix. Mycorrhizal fungi, which are found in undisturbed soils, may be missing.
These fungi help native plants absorb water and nutrients from the soil, leading to better growth. A native plant growing in the home landscape may be growing in an altered environment.
A third misconception is that native plants are always more desirable than non-native species. Poison ivy and poison sumac are natives, but they are far from desirable. Some natives are aggressive growers, spreading rapidly.
They may overwhelm a small yard or may not fit well in a traditional landscape. As with any plant group, careful selections need to be made.
"When selecting native plants, consideration should be given to the plant's natural habitat," she noted. "Each species developed in a specific habitat and will grow best when given conditions that resemble that habitat.
"Some species developed in wooded sites so shade will be needed. Woods, however, may be dense or open, so different plants tolerate varying degrees of shade. Plants from open woods may be able to tolerate a fair amount of sun. Other species developed in open areas like prairies and fields. These plants are usually going to need full sun." There is some overlap with habitats. Plants that are considered wetland plants developed in wet sites, such as swamps and stream banks, and need a consistent amount of water (but not necessarily wet soils).
Wetland plants may be found in wooded areas that are wet and these plants would have a need for shade. Other wetland plants may have developed in wet meadows or prairies and thus would need full sun.
"Every native plant will not be a good match for every garden," she noted. "Remember that some native plants can be aggressive in their growth, so that factor must also be considered, especially if the plant will be placed in a small garden. If naturalizing is the goal, however, plants that are aggressive growers or self-sowers could be considered desirable."
Not all native plants are attractive, and that should be taken into consideration. This is a subjective decision that each gardener must make. Another subjective choice, but a far more serious one, is the matter of poisonous plants. Among both introduced plants and natives, there are plants that may be harmful to some degree and others, like water hemlock, that are deadly.
"Safety should always be a concern in the garden," she said. "Don't select a plant without knowing more about it, whether it is a native or introduced plant."
Other considerations in native plant selection are the ones we use in selecting any type of plant: hardiness, size, bloom time and color. "Do not collect plants or seeds from wild areas as this may endanger a particular stand of plants and may be illegal," she cautioned. "Buy plants and seeds from reputable nurseries that are propagating plants rather than collecting from the wild." You can have native plants in the garden without going completely native. Some gardeners want only native plants, while others will mix native and introduced species together in the same garden. This can be done as long as the plants have the same cultural needs (water, light, etc.).
"Also consider how the plants will look together. One clipped yew in the middle of a wildflower mix might look a little odd," Yiesla said.
For more information on native wildflowers, go to http://urbanext.illinois.edu/wildflowers/ .