Invasive species and invasive species management change with the seasons. Some invasive species are more recognizable at certain times of the year and the success of control techniques often depend upon the right timing. The River to River CWMA is creating a series of article about invasive species in the different seasons. Be sure to also read THIS article on invasive species in summer.
With the arrival of autumn comes the changing of the colors of leaves and the ripening of fruits. Along with that, also comes the opportunity to easily find woody invasive plants. Many of these invasive species turn distinctive colors or stay green longer than native species, allowing for easy identification. Also, with the cooler temperatures, the disappearance of ticks and chiggers, and the senescence of posion ivy, it is a great time to be out in the woods.
Here are some tips on what to look for when identifying some of our common woody invasive plants.
Oriental bittersweet is a woody vine that climbs up and over trees and shrubs, particularly along forest edges. In the fall, bittersweet leaves turn a bright yellow color and the fruit on female plants mature and the covering splits open to reveal scarlet red berries (called arals). Look for the yellow leaves surrounding the trucks of trees or draping over the top of shrubs or lower branches of trees.
Bush honeysuckle is a shrub that can be found growing along the edge or within the interior of a forest. Like bittersweet, it also has yellow leaves and bright red berries. Bush honeysuckle is unique in that it is often one of the last plants to remain green in the fall and one of the first plants to green up in the spring. In the fall, looking for honeysuckle shortly after the trees have lost their leaves is often the best time to spot this species. Look for small shrubs (10-15 feet tall) densely covered in leaves that are dark green turning to bright yellow.
Burning bush is a common ornamental shrub used in landscaping, but is starting to spread into wildlands in southern Illinois. This species is instantly recognizable in the fall by its bright red fall color and its upright growth form. Late in the fall, burning bush levaes turn from a dark green to a deep red in color. Often, during this turn, the leaves will have somewhat of a purplis or maroon tinge. Upon closer inspection, the branches will usually show some type of corky wings.
Autumn olive is large shrub or small tree that is very common across southern Illinois, particularly in grassland or field settings. This species also keeps its leaves longer than most of our native species. When it still has its leaves, autumn olive can be recognized by the silvery coloration of the underside of the leaves. This coloration gives the entire plant a shiny, silverly sheen that stands out and separates it from any other shrub species.