Saltcedar (Tamarix ssp.) or tamarisk was introduced to the United States in 1823 on the east coast.
It was originally planted as an ornamental, to create wind breaks and to provide shade and stabilize stream banks, but its negative impacts have surfaced within the last few decades.
Saltcedar was first reported escaping cultivation in the 1870s. In the southwestern United States, it quickly out competed native willows and other riparian shrubs and reduce water levels.
Although arid regions of the southwest have been hardest hit by tamarisk species, there are increasing reports of saltcedar invading grasslands in the Dakotas and western Minnesota.
To better understand the threat that saltcedar poses to Minnesota, it was selected for evaluation by Minnesota Department of Agriculture’s noxious weed advisory committee. Tamarisk is a group of species of old-world shrubs originating from southern Europe, northern Africa and western Asia.
It develops scale-like leaves that produce clusters of pink or white flowers along terminal ends. It is called saltcedar because of the cedar-like leaves and the ability to increase soil salinity surrounding infestations.
Tamarisk is a prolific seed producer and can continually produce seeds throughout the entire growing season in lower-elevation areas. In the southwest, tamarisk establishes quickly in areas where water pools (river banks, low elevation drainage basins), and have been reported overtaking 90 percent of native vegetation along corridors of the Colorado River system.
Tamarisk develops an extensive taproot that reduces the water table height – reducing available water for the surrounding native species. Deep taproots take up saline water, and then excess salts are expelled from the leaves. This increases the soil salinity which inhibits the growth of other plants.
Tamarisk is difficult to control. It responds well to a combination of cutting and herbicide applications when timed correctly, and a tamarisk biocontrol beetle is used readily in the southwestern United States.
Herbicides have not been effective unless they are applied during a short window before the leaves drop. Naturalizing tamarisk populations have not been reported in Minnesota.
If you suspect that you have found a tamarisk species that has escaped cultivation, please do the following:
• Note the exact location with address or GPS coordinates.
• If it is possible, take digital photos of the whole plant, rosettes, flowers and seed stalks that can be e-mailed for identification. Infestations can be reported to the MDA by e-mail at email@example.com, or voice mail 1-888-545-6684.
– Christina Basch is a noxious weed eradication specialist for the Minnesota Department of Agriculture
– Image courtesy of the Minnesota Department of Agriculture