The Bugwood Network

Silverthorn, Thorny Olive
Elaeagnus pungens Thunb.

International Code - ELPU2
FIA survey code - 2037


Miller, James H. 2003. Nonnative invasive plants of southern forests: a field guide for identification and control. Gen. Tech. Rep. SRS–62. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southern Research Station. 93 p.

acrobat version

Plant. Evergreen, densely bushy shrub 3 to 25 feet (1 to 8 m) in height, with long limber projecting shoots, scattered thorny branches. Thick leaves, silver-brown scaly beneath. Often found as escaped single plants from animal-dispersed seeds.

Stem. Multiple stems and densely branched. Twigs brown and dense with brown scales and hairy when young. Short shoots with small leaves becoming sharp-branched or unbranched thorns 0.4 to 1.6 inches (1 to 4 cm) long, and in second year producing leafy lateral branches, followed by flowers in fall. Lateral branches distinctly long, limber, and in late summer to spring extending beyond bushy crown and ascending into trees. Bark dark drab and rough with projecting thorns.

Leaves. Alternate, oval to elliptic and thick, 0.4 to 4 inches (1 to 10 cm) long and 0.2 to 2 inches (0.6 to 5 cm) wide. Irregular and wavy margins. Blade surfaces silver scaly in spring becoming dark green or brownish green above and densely silver scaly with scattered brown scales beneath. Petioles 0.1 to 0.2 inch (4 to 5 mm) long, grooved above.

Flowers. October to December. Axillary clusters, each with one to three flowers, 0.4 inch (1 cm) long, silvery white to brown. Tubular with four lobes. Fragrant.

Fruit and seeds. March to June. Oblong, juicy drupe, 0.3 to 0.6 inch (1 to 1.5 cm) long, containing one nutlet. Whitish ripening to red and finely dotted with brown scales. Persistent shriveled calyx tube at tip.

Ecology. Fast-growing, weedy ornamental. Tolerant to shade, drought, and salt. Spreads by animal-dispersed seeds and occurs as scattered individuals, both in the open and under forest shade. Increases in size by prolific stem sprouts. Can climb into trees.

Resembles autumn olive, E. umbellata Thunb., and Russian olive, E. angustifolia L., both of which are deciduous and are further described in this book. Autumn olive has thin leaves with silver scales (not silver brown) and abundant reddish rounded berries in fall and early winter. Russian olive has silver scaly twigs and leaf surfaces, and many yellow olives in fall and winter.

History and use. Introduced as an ornamental from China and Japan in 1830. Frequently planted for hedgerows and on highway right-of-ways and still used for landscaping.


October
Photo by J. Miller


March
Photo by T. Bodner


April
Photo by J. Miller


October
Photo by J. Miller


April
Photo by J. Miller


States with suspected infestations are shown in gray.


Recommended control procedures:

  • Thoroughly wet all leaves with Arsenal AC* or Vanquish* as a 1-percent solution in water (4 ounces per 3-gallon mix) with a surfactant (April to October).
  • For stems too tall for foliar sprays, apply Garlon 4 as a 20-percent solution in commercially available basal oil, diesel fuel, or kerosene (2.5 quarts per 3-gallon mix) with a penetrant (check with herbicide distributor) to young bark as a basal spray (January to February or May to October). Or, cut large stems and immediately treat the stumps with one of the following herbicides in water with a surfactant: Arsenal AC* as a 10-percent solution (1 quart per 3-gallon mix) or a glyphosate herbicide as a 20-percent solution (2.5 quarts per 3-gallon mix).

*   Nontarget plants may be killed or injured by root uptake.


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USDA Forest ServiceUSDA APHIS PPQThe Bugwood Network University of Georgia Bargeron, C.T., D.J. Moorhead, G.K. Douce, R.C. Reardon & A.E. Miller
(Tech. Coordinators). 2003. Invasive Plants of the Eastern U.S.:
Identification and Control. USDA Forest Service - Forest Health
Technology Enterprise Team. Morgantown, WV USA. FHTET-2003-08.