Weed of the month submitted by John Lamman Saltcedar
Saltcedar (Tamarix spp.) was first introduced as an ornamental plant to the eastern United States from southern Europe, northern Africa, and eastern Asia as early as the 1820’s. The expansion of this invasive plant began during the late 1800’s into rivers and streams in the southwestern United States. It was introduced to the western states between 1900 and 1940 to facilitate water transportation, reduce flooding and sedimentation, and to enhance irrigation return flows. Since then, salt cedar has invaded most, if not all, areas where surface and subsurface water occurs. In 2003 it was estimated at about 3/6 million acres (1.4 million ha) in 17 western states was infested by Tamarix spp..
As a prolific seeder over an extended period (April to October), early seedling recruitment is very slow, but once established, seedlings grow faster than native plants. Once mature, the plant becomes well established with deep roots that occupy the capillary zone above the water table with some roots in the zone of saturation.Saltcedar can quickly dominate an area, out-competing native plants for sunlight, moisture, and nutrients.Mature plants can withstand prolonged drought or periods of inundation.
The plant also brings salts to the surface by excreting it through leaves and dropping it onto the soil surface below the canopy. Only extremely xeric or halophytic species of plants can tolerate the understory environment of saltcedar. As a result, the plant commonly forms a near monoculture where it grows.
During my career with the U.S. Forest Service and U.S. Bureau of Land Management, I have worked in riparian areas that were so infested with saltcedar, that it was difficult to find a place to cross the river or stream. The methods of treatment we have used to manage saltcedar include: foliar application of herbicide, cut stump (herbicide applied to stump), and hydro-ax (herbicide applied to sprouts). Our partners in the Fremont County area have released tamarisk beetles (Diorhabda carinulata) that defoliate saltcedar. Those beetles are now migrating to new areas where they causing adverse effects on saltcedar.
John is the Rangeland Management Specialist at the BLM Royal Gorge Field Office.