Tamarisk - aka 'Saltcedar' (Tamarix ramosissima)

Introduced in the United States in the late 1800's, hundreds of thousands of acres of rivers, riparian corridors and springs have been invaded by tamarisk, outcompeting native species and altering the hydrology of the ecosystem. In the Las Vegas Wash, tamarisk has gained a foothold, representing 80% of the vegetation, approximately 1,500 acres.

Managing invasive plants such as tamarisk is an important part of the overall revegetation effort. Pictured here, the root crowns are removed from the soil. Mechanical control is one of several effective methods to control tamarisk.

An Aggressive Competitor
Without any natural predators in the United States, there are several ways that enable tamarisk to outcompete native plant species in the southwest. Tamarisk has the ability to transpire large quantities of water coupled with a fast growing taproot. This combination enables this weed to draw down the water table, preventing other plants' roots from reaching the soil moisture. Another competitive feature of tamarisk is its reproductive timing. It seeds earlier in the season than its competitors such as cottonwoods and willows. Without this competition from other these native species tamarisk releases million of seeds that can spread easily throughout the Wash floodplain, establishing quickly on sandbars and along the streamside. As these plants become increasingly more prevalent, there is less room for natives to establish. A copy of the Weed Wanted Poster is available courtesy of University of Nevada, Reno.

Control Program
The Las Vegas Wash Weed Partnership has ranked tamarisk 3rd in its Top Three Hit List. Because of the extent of the infestation of the tamarisk in the Las Vegas Wash the tamarisk management program is geared for controlling the species. Tamarisk is removed in specific areas based on the revegetation program. As of spring 2005, approximately 60 acres of tamarisk have been cleared and revegetated with willows, cottonwoods and other native species.

In 2003, approximately 1,500 acres of salt cedar were reported within the lower Las Vegas Wash, which is defined as the nine mile stretch of the Wash from Vegas Valley Drive to Lake Las Vegas. The saltcedar infestation was mapped using aerial photography and a geographic information system (GIS). In 2007, saltcedar infestations were remapped with three goals in mind. The first goal was to show the extent of saltcedar along the lower Wash. The second goal was to document the reduction of acreage as a result of removal/management projects. The third goal was to determine if the saltcedar had infested new previously undocumented areas within the lower Wash. When the remapping of the saltcedar was complete the actual infestations showed 530 acres. This shows that there has been a reduction of almost 1000 acres with very little new infestations previously undocumented. The removal of the large dense stands of saltcedar have been classified into two major types of removal 1) removal associated with LVWCC projects including erosion, restoration, etc. and 2) removal by housing developers, etc. Approximately 200 acres of saltcedar has been removed by the LVWCC for erosion, restoration, etc. and approximately 770 acres for adjacent housing developers, etc.