Tamarisk or Salt Cedar
 (Tamarix parviflora, T. ramosissima)

County Management Strategy: Biological control throughout the County.

Identification: A small tree or shrub growing up to 20 feet tall, with feathery leaves and tiny purple to white flowers. May be deciduous or evergreen, but mostly deciduous in our area. This plant grows in riparian areas and wetlands, often depleting surface water and lowering ground water levels. Salt is released from the leaves when they drop in the fall, making the soil in the understory highly alkaline.

Other names: Small flower tamarisk, tamarix, tamarack (locally)

Similar species: No other shrub is similar in appearance to these Tamarix spp.

Control timing: Year round, with best success in fall and winter with cut-stump and basal spray treatments.

Control target: Prevent seed production and stress root system.

Control methods: A detailed tamarisk control publication is available at CSU Cooperative Extension or the Division of Pest Management. Brush hogging and burning lead to less successful control due to the vigorous regrowth that occurs. Cutting down the shrub or tree in the fall, winter or spring and painting the stump surface immediately afterward with an herbicide (cut stump treatment) is the most effective control method. Herbicide must be applied within 10- 15 minutes of cutting to prevent excessive resprouting from the stump. Follow up herbicide application is needed to treat sprouts from the root system. This usually will only be necessary for 2-4 years. All branches and trunk pieces must be removed from the site to prevent sprouting. Tamarisk branches touching wet ground have been known to sprout and send down new roots. Chipping or burning the slash is recommended. The basal 12-18 inches of the trunks of young plants with smooth bark can be sprayed with herbicide (basal bark treatment). Rough barked plants should get the cut stump treatment. Foliar sprays during the growing season must cover the entire leaf surface to be effective and will take 3-4 years of repeated treatment to be successful. "Root plowing" may be effective in certain areas, but care must be taken to remove the root below the crown. This method disturbs a large area of ground and should be used only in large dense stands where no native plants occur. A leaf feeding beetle (Diorhabda elongata) is currently established and spreading along the Dolores and Colorado Rivers. Several years of defoliation by the insects are necessary to kill the plant.

Status in Mesa County: Tamarisk is a plant that is “preferred to be controlled”, rather than “mandatory for control” in Mesa County. It is widespread throughout the county in most riparian zones of permanent and ephemeral streams. Although thought to be a lower elevation plant, tamarisk has been found on Douglas Pass in Garfield County and near McClure Pass in Gunnison County.

Photos:
http://www.cwma.org/tamarisk.html

Fact sheets and control:
http://www.cpluhna.nau.edu/Biota/tamarisk.htm
http://www.ecy.wa.gov/programs/wq/plants/weeds/aqua013.html

Additional Links:
http://www.tamariskcoalition.org/