Elaeagnus pungens

Common Name(s): Silverthorn

Non-Native to Florida

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.

Cultural

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

Mechanical

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

Biological

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

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

USDA Natural Resources Conservation Service. Plants Database

Invasive Plants of the Eastern United States

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.

The Plant Conservation Alliance’s Alien Plant Working Group. Weeds Gone Wild: Alien Plant Invaders of Natural Areas

Pacific Island Ecosystems at Risk (PIER). Plant Threats to Pacific Ecosystems

Floridata Homepage

The Hillsborough County Invasive Species Task Force

Identification and control of non-native invasive plants in the Tampa Bay Area

Excerpted from

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

Description modified January 2014 using Citation #1 below

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Citations

1. Invasive and Non-native Plants You Should Know – Recognition Cards, by A. Richard and V. Ramey. University of Florida-IFAS Publication # SP 431. 2007.

2. Integrated Management of Nonnative Plants in Natural Areas of Florida, by K. A. Langeland, J. A. Ferrell, B. Sellers, G. E. MacDonald, and R. K. Stocker. University of Florida-IFAS Publication # SP 242. 2011.

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