Weed of the Week: saltcedar

My great aunt farmed for her whole career. She used to say, “a sharp hoe is as good as a rain any day.”

And there are weeds where no registered chemistry is available, or that can be applied in riparian areas so removal is one of the only options.

Saltcedar is one of those, and has been moving into Western Canada slowly, but steadily.

It is the type of pest that makes droughts droughtier.

Thought of a dry-range plant, saltcedar is often seen along edges of dry ditches or streams or on dugout banks; it loves wet feet. It’s a heavy water user despite having a reputation for surviving droughts. Mature plants draw up to 800 litres per day in summer. So the case for control is a strong one, especially in areas where water is short.

Researchers at the University of Manitoba have been modelling the spread of the pest and have shown it has potential for expansion throughout Western Canada.

Producers who deal with it and purple loosestrife consider saltcedar the worst of the two pasture pests.

Saltcedar, also known as tamarix, was found in southern Saskatchewan in 2011 and Alberta before that.

In the United States, it is estimated to cover more than one million acres.

Saltcedar was first a solution before it became a problem. Imported to improve riparian areas by stabilizing stream banks and creating windbreaks in arid and otherwise inhospitable regions, its pink flowers were welcomed by those trying to hold back dust or eroding soils along waterways.

It can take submersion, drought and salt. Its taproots, capable of descending 30 metres and spreading more than twice that distance, can sustain the pest under the most arid conditions.

All that water it pumps can carry a lot of salt, which the saltcedar concentrates and excretes through leaves that fall and mix into the soil, killing non-salt tolerant plants in the area, eliminating its competition. The pink-flowered, deciduous plant is tolerant of nearly everything but shade.

Saltcedar has taken over large cottonwood and willow stands in the U.S., leaving the soil saline and difficult to reclaim.

The diamond-shaped leaves are bright green and structured like those of cedar plants. The thin leaves turn yellow in fall.

The flowers form in finger-like clusters and are two to five centimetres long. Seeds are in three to four millimetre long capsules, are less than half a mm long and have a hairy tuft at one end. These copious seeds are a primary source of reproduction, but buried branches and stems are also capable of sprouting.

Waterways in Montana and North Dakota, including the Fort Peck Reservoir and Yellowstone River have established, dense stands, creating strong opportunities for habitat expansion.

In many cases excavating machinery or recreational boats will unknowingly carry seed to new locations.

Tamarix ramosissima, Tamarix pentandra, Tamarix chinensis and Tamarix parviflora forms of the pest are all present in North America and are all problems.

Cattle and sheep will eat the plant, but trampling in riparian areas can create its own issues that the pest was originally brought in to solve.

Cutting followed by cultivation can be effective, but complete control is difficult with this method alone. Imazapyr and glyphosate are effective on foliage. Triclopyr and imazapyr are useful for cut stumps and stems. Application of herbicides in wetland areas may require certified applicators to do the work.

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