Plants That Won't Stay Put
we plant them and may require special watering, fertilizing, or protection from the heat or cold to keep them healthy.
In Missouri, about 800 exotic plant species (26 percent of our flora) grow outside of cultivation. A small percentage of these exotic plants have spread so rapidly into native ecosystems that they out-compete and replace native species. The result of the continued spread of exotic plants will be a less interesting planet in which a few aggressively spreading, globetrotting species dominate or change the character of many diverse and distinctive regional landscapes.
Some exotic plants may seem beneficial because they can control erosion. Others are desirable because they grow quickly or provide food for wildlife. Over time, however, people have repeatedly failed to consider the many undesirable effects of exotic species.
Shrub honeysuckles, for example, provide abundant fruits that are eaten by birds, but recent studies show that birds nesting in shrub honeysuckles lose more eggs or young to nest predators than birds nesting in native shrubs. Our short-sightedness also led to the widespread establishment of multiflora rose, kudzu, purple loosestrife and teasel. The time for caution is before planting because, once established, exotic plants may resist our efforts to control or eradicate them.
The Missouri Department of Conservation has identified a number of exotic plants that are capable of aggressively spreading into our native ecosystems. We work to eradicate or control these species on public lands that we manage. While some of these plants are still sold commercially, planting them can put nearby native habitats at risk.
Some readily identifiable problem species are described below. Descriptions and control methods for the species shown here, as well as others, are available on the Department's website at <www.mdc.mo.gov/nathis/exotic>. Once you access that web page, select "Vegetation Management Manual." You can also obtain control recommendations for particular species by writing to: Natural History Division, Missouri Department of Conservation, P.O. Box 180, Jefferson City, MO 65102-0180.
Shrub or Bush Honeysuckles Lonicera maackii and Lonicera morrowii
In contrast to our native honeysuckles, which are twining vines, these Asian honeysuckles are shrubs.
They have been planted as ornamentals and as wildlife food plants. Birds eat the fruits and spread the seeds. Where shrub honeysuckle grows, it often replaces the native shrubs and eliminates woodland wildflowers from the forest floor. This completely changes the character of the forest understory to the detriment of native plants and animals. Many forests near Missouri's urban areas have