The Marberry Arboretum should be considered a "diamond
in the rough" because there are many gems but their beauty
and value cannot be fully appreciated because of the presence
of aggressive weeds. Some of these weedy species are problems
all over southern Illinois, such as autumn olive, multifloral
rose, and Japanese honeysuckle. It is unlikely that these species
were purposely introduced into the Arboretum. Conversely, a number
of invasive species are very likely derived from exotics that
were purposely planted here. These include English ivy, Japanese
Wisteria, Mahonia, and Periwinkle. These plants demonstrate that
it is difficult to predict whether a cultivated plant will "escape"
and become weedy. See the article by Mark Basinger entitled "Notes
on some naturalized woody plant species new to Illinois"
(Trans. Illinois Acad. Sci. 91:33-36; 1999. Get pdf file HERE).
In that article he reports naturalization of several species planted
at the Arboretum that have potential to become invasive in the
future (e.g. Acer palmatum, A. campestre, and Viburnum
dilatatum) . These examples highlight one of the important
missions of the Arboretum, that is, to inform the Southern Illinois
public about which species should be avoided owing to their invasive
tendencies.
Below are listed ten of the most troublesome invasive species
found in the Arboretum, some of which have photographs linked
to them (more to come!).
Clicking
on the "hot" word below will open the photo in a separate
window. Simply close the window when finished viewing (this page
should remain open).
Acer negundo (Box Elder)
Elaeagnus angustifolia (Russian Olive)
Elaeagnus
umbellata (Autumn Olive) - the shrub with whitish leaves
towards the front. The tree in the back is Zelkova.
Euonymus fortunei (Wintercreeper Euonymus)
Hedera helix
(English Ivy). Found covering the ground as well as many tree
trunks and branches.
Lonicera japonica (Japanese Honeysuckle). The vine growing on another invasive, Autumn
Olive. Too bad one can't eliminate the other! Close-up view of
the flowering
vine and the flowers.
Although it looks beautiful and smells great, this species is
one of our most invasive and persistent weeds in Southern Illinois.
Lonicera maackii (Amur Honeysuckle)
Lonicera tartarica (Tatarian Honeysuckle)
Rosa
multiflora (Multifloral Rose). The white flowers are from
the rose which clambers throughout the other vegetation.
Wisteria
floribunda (Japanese Wisteria) top right and English Ivy
in the middle. Wisteria
shown twining around a tree. Note the scars left on the tree
bark caused by the vines.