University of Nebraska-Lincoln Extension, Institute of Agriculture and Natural Resources

September 8, 2006

September optimal for controlling saltcedar

Saltcedar
(Photo courtesy of Mr. and Mrs. Robert G. Young @ USDA-NRCS PLANTS Database / USDA NRCS. 1992. Western wetland flora: Field office guide to plant species. West Region, Sacramento, CA.)
Nebraska's newest official noxious weed is saltcedar (Tamarix ramosissima Ledeb) and (Tamarix parviflora DC), also known as tamarisk. It is an invasive weed found in all soil types of Nebraska's wetland habitats. It is a perennial deciduous or evergreen shrub or small tree (Tamaricaceae) that reproduces both by seed and perennial structure such as taproot and stem. Its root system is extensive and its primary taproot can easily grow at least 15 feet deep and when searching for moisture, it has been know to grow as deep as 150 feet.

Once the water table is reached, secondary root branching becomes profuse. It can grow as an individual tree or in sparse groups. Its woody stem is erect, up to 20 feet tall, bark-brown or reddish-brown with highly branched saplinks. Leaves are small and scale-like (as in many cedar trees) with many divisions on slender, highly branched green stems.

In Nebraska, saltcedar can flower from June to August with small pink flowers on the top of the main woody stem and branches (saplinks) in finger-like clusters. The flowers produce numerous small tufted seeds that can be carried long distances by wind and water. The seeds, however, have a short period of viability, and must come in contact with suitable moisture within a few weeks of dispersal.

Saltcedar was sold as an ornamental plant species, but escaped and became naturalized along streams, canals and reservoirs in much of the western United States. In addition, in the early 1900s saltcedar was purposely planted along stream banks for soil erosion control.

Environmental damage Saltcedar affects the natural habitat in several detrimental ways. Its high evapo-transpiration rate can lower the water table in streams and canals. The salt excreted from the leaves to the soil surface under the plant inhibits germination and growth of competing species. (The name “saltcedar” is derived from the salty residue that collects on the small scale-like leaves.) As a result, many wildlife species are negatively affected by habitat changes and native species displacement due to encroachment of saltcedar. In addition, the sticky salty substance exuded by the leaves can also damage the plumage of birds. With loss of habitat most wildlife species move to more diverse native plant communities.

Control guidelines

Due to its detrimental effect on the wildlife habitat and land in general, saltcedar needs to be controlled on private and government lands.

  1. Treat when plants are under 6 feet tall and easier to control.
  2. Treat areas previously root-plowed or mowed or areas where saltcedar appears to be newly invading.
  3. Treat areas with tree densities of fewer than 150 plants per acre.
  4. Spray foliage to wet (no dripping) especially terminal ends, and allow two full growing seasons before follow-up management.
  5. Time herbicide applications to have the greatest effect. September and August treatments are much better than May, June or October treatments.
  6. Broadcast treatments can be done using airplane, helicopter or high-clearance sprayers with a water volume of a least 15 gallons per acre for better penetration into the dense canopy. Arial application can be effective using a global positioning spray system matched with the survey maps, allowing the pilot to locate saltcedar sites and exclude sensitive areas such as cottonwood groves and other vegetation. For broadcast treatments Habitat (imazapyr) is recommended at the rate of 3 pints per acre.
  7. Individual trees also can be controlled with Habitat at 1% volume/volume (v/v). Habitat is absorbed through foliage and roots and is translocated throughout the plants. Complete kill of plants may not occur within a month or two. A mixture of Roundup (0.5% v/v) and Habitat (0.5% v/v) also is effective. Roundup is added to the mix to reduce the cost of the treatment
  8. Do not treat irrigation ditches and water for domestic use. Do not use near desirable trees and near homesteads.
  9. Clean equipment with water after spraying.

Stevan Knezevic
Extension Weeds Specialist
Haskell Ag Lab, Northeast REC

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Copyright 2006 by the University of Nebraska Board of Regents. All rights reserved.
Published by University of Nebraska-Lincoln Extension in the Institute of Agriculture and Natural Resources Cooperating with the counties and the U.S. Department of Agriculture.
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