Silverthorn

Elaeagnus pungens-- Center for Aquatic and Invasive Plants

Elaeagnus pungens

Non-Native in Florida

Elaeagnus pungens

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Elaeagnus pungens Elaeagnus pungens Elaeagnus pungens Elaeagnus pungens Elaeagnus pungens

CATEGORY II on the Florida Exotic Pest Plant Council's (FLEPPC) 2013 List of Invasive Plant Species

Download a Recognition Card (PDF 980 KB)
For control information, see Integrated Management of Nonnative Plants in Natural Areas of Florida (SP 242)
by K. A. Langeland, J. A. Ferrell, B. Sellers, G. E. MacDonald, and R. K. Stocker




    Introduction

    In the early 1800’s Elaeagnus pungens, or silverthorn, was introduced from China and Japan as an ornamental plant. Silverthorn is used in the United States as a landscape plant, often grown as an evergreen hedge and barrier and is regularly planted along highways. Unfortunately, many Florida nurseries and homeowners are not aware the Florida Exotic Pest Plant Council considers this plant a Category II invasive exotic species. This means silverthorn has the potential to cause ecological damage by altering native plant communities by hybridizing with native Elaeagnus species, displacing native species, and changing community structures or ecological functions.

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    Description

    Elaeagnus pungens is an evergreen shrub that is able to grow 3 to 25 feet in height. Although silverthorn is primarily considered a shrub, it also can take the form of a climbing plant, growing over and shading out other plants. Take caution when handling this plant. Its common name, silverthorn, comes from the thorns on its branches.

    Leaves are lanceolate with entire to wavy margins arranged alternately on the stem approximately 2 to 4 inches long (0.2 to 2 inches wide). Upper leaf surfaces are waxy green and scaly. Lower leaf surfaces are silvery and scaly, as is the petiole. To the touch, leaves are rough and grainy. The bark is reddish brown in color, having lenticels (small spots) when older, smooth when young.

    Flowers are 1/2 to 5/8 inch long, pale yellow to white, bell shaped with a sweet smelling fragrance. These are borne in axillary clusters of one to three flowers in the fall. The fruit are drupes, round and red in color with silver scales.

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    Impacts

    Silverthorn is a fast-growing, weedy ornamental. It is able to grow and thrive in a variety of conditions, and can tolerant shade, drought, and salt. Animals and birds disperse seed, widening its area of distribution. Reproduction also occurs via stem sprouts. When silverthorn is in the climbing form, it can climb into trees, leading to the displacement of native vegetation.

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    Management

     

    Preventative:

    Remove all silverthorn plantings to prevent the spread and dispersal of seed. Educate the public on the potential dangers of invasive plants to prevent future plantings.

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    Cultural:

    Remove plants prior to seed production.  Revegetate natural areas with native species.

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    Mechanical:

    Aggressive tillage and/or mowing is an option whenever possible.  Repeat as needed to control regrowth. 

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    Biological:

    Silverthorn has very few pests or diseases in landscapes. There are no known biological agents.

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    Chemical:  

    Foliar applications of imazapyr or glyphosate with a surfactant in water have been used to treat silverthorn. Triclopyr as a 20% solution in a petroleum base with a penetrant can be used for upper stem treatments, as well as to young bark as a basal spray. Large stems can be cut and stumps treated immediately with imazapyr (10% solution), triclopyr (50% solution) or glyphosate (20% solution) in water with a surfactant.

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    References and Useful Links:

    Invasive Plants of the North America

    University of Florida Center for Aquatic and Invasive Plants

    University of Florida’s Cooperative Extension Electronic Data Information Source

    Langeland, K.A. and K. Craddock Burks. 1998. Identification and Biology of Non-Native Plants in Florida's Natural Areas. IFAS Publication SP 257. University of Florida, Gainesville. 165 pp.

    USDA Natural Resources Conservation Service. Plants Database

     

    Excerpted from the University of Florida, IFAS Extension, Circular 1529, Invasive Species Management Plans for Florida, 2008 by:

    Greg MacDonald, Associate Professor Jay Ferrell, Assistant Professor and Extension Weed Specialist
    Brent Sellers, Assistant Professor and Extension Weed Specialist
    Ken Langeland, Professor and Extension Weed Specialist Agronomy Department, Gainesville and Range Cattle REC, Ona
    Tina Duperron-Bond, DPM – Osceola County
    Eileen Ketterer-Guest, former Graduate Research Assistant

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