Autumn Olive

Glenn Nice, Weed Diagnostician, Department of Botany & Plant Pathology, Purdue University

In honor of June being Invasive Species Awareness Month in Indiana, I thought I would highlight one of the plants that is being considered an invasive species.  Autumn olive is a shrub that can be found across the state of Indiana.  This week’s picture of the week comes to you from the Eagle Creek Park in Indianapolis.  Autumn olive has spread rapidly across Indiana.  In 100 Years of Change in the Distribution of Common Indiana Weeds by William and Edith Overlease (2002) reported that autumn olive was not found in Indiana in 1899 (Coulter’s Catalogue of Indiana Plants) or in 1940 (Deam’s Flora), but could be found in every county in 2002.  Originally from Asia, autumn olive was introduced to the U.S. in 1830 (1).  It was often planted for wild life habitat, but its aggressive proliferation can impact natural areas.  Although planting or having autumn olive is not regulated in Indiana, it is recognized as an invasive species by several organizations and not recommended.  The states of Connecticut, Massachusettes, New Hampshire and West Virginia also mention autumn olive on their noxious, prohibited or invasive plant lists (2).

Autumn olive is a shrub ranging in height from 3 up to 20 feet.  It’s most distinguishable character is the silvery surface of the underside of the leaf.  The top of the leaf is dark green with or without a light dotting of silver.  This silvery appearance comes from scales which are oddly shaped plant hairs (trichomes) and is characteristic of olive species.  Leaves are alternate, oval to oblong.  In April or May light yellow flowers bloom then produce a small fleshy fruit that is generally red in color.  A close relative to autumn olive is Russian olive, also considered an invasive plant.  Russian olive is a shrub or tree with silvery leaves on both sides.  For more information on autumn or Russian olive please see the following web resources.

1) USDA: http://www.invasivespeciesinfo.gov/plants/autmnolive.shtml#fed

2) USDA State Noxious Weed Reports: http://plants.nrcs.usda.gov/cgi_bin/noxious.cgi

Other web resources:

Indiana Invasive Plant Assessment Work Group (IPSAWG) - pdf file

University of Pennsylvania - pdf file

Virginia Tech Weed Identification page

Maine Invasive Plants

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