Invasive
Species to Watch: Winged Burning Bush
That’s
invasive!? Winged burning bush (Euonymus
alatus) is a favored plant in landscaping, and many people
are unaware of its aggressive, invasive tendencies once the seeds are dispersed
by birds. There are many cultivars of burning bush - loved for its brilliant
red fall foliage and its ability to be pruned and shaped into almost any form. Burning
bush is hardy up to zone 4, and grows in almost any soil conditions except
continually moist soils - one of the reasons it is often overused in the
landscape. However, there is a dark side to this horticultural favorite - so
dark that it is now banned for sale and propagation in Connecticut, Massachusetts,
and New Hampshire. In a study on its invasiveness, cultivars had an estimated
seed production that ranged from 588 to 3763 seeds per plant, and 40% of seeds
could produce new plants. Therefore, each year, it is conservatively estimated
that one burning bush on private property may be sending more than 235 young
plants into adjacent land. These new seedlings have the potential to form dense
thickets and displace the local native plant species.
It is easily distinguished from native and other
invasive look-alikes by the greyish-brown, corky, winged structures on the
young green stems. Leaves are about 2 inches long, elliptical with a pointed
tip, finely toothed along edges, and oppositely paired along the stem. Small flowers
with four yellowish-green petals appear in May. Green fruits mature throughout
the summer. In the fall, the outside fruit capsules turn red to brownish-purple
and split to reveal fleshy, red arils, which birds disperse. Depending on the
cultivar, plants may reach heights of 12 feet tall or more. Unfortunately,
burning bush is becoming a common sight in the forests of southern Illinois and
is no longer recommended for planting by conscientious land managers. Although a sterile cultivar of burning bush
has been developed, there are several native alternatives, which offer very
attractive replacements in landscaping, such as red chokeberry (Aronia arbutifolia), large fothergilla (Fothergilla major), Virginia sweetspire
(Itea virginica), Blackhaw (Viburn prunifolium), shining sumac (Rhus copallinum), and Eastern wahoo (Euonymus atropurpureus).
There
are several ways to control burning bush. Small seedlings can be hand-pulled. Shrubs
can be cut and treated with a systemic herbicide, such as glyphosate or
triclopyr. Cut surfaces should be treated with herbicide in less than 10
minutes following cutting, so that the cut surface does not dry and prevent
herbicide uptake. A basal bark application of herbicide (triclopyr in oil) may
also be used if cutting the plant is not desirable. A foliar herbicide
application may be used at a low rate (2 – 4%) for small plants. Always follow
label instructions when applying herbicides and wear the appropriate protective
gear.
Please
help encourage others to landscape with native or non-invasive species. If you
find escaped burning bush in Illinois natural areas, please report these
sightings by visiting EDDMaps at the River to River CWMA website
(http://www.rtrcwma.org/report). Please
contact Karla Gage, CWMA coordinator, with questions: 618-998-5920 or rtrcwma@gmail.com.
Reference:
Brand,
M. H., Lubell, J. D. & Lehrer, J. M. Fecundity of Winged Euonymus Cultivars
and Their Ability to Invade Various Natural Environments. HortScience 47, 1029–1033 (2012).
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Article originally published in the September 2013 Williamson County Soil and Water Conservation District newsletter.
