What’s That Weed?

Invtroduced species:  Saltcedar (Tamarix ramosissima)

Characteristics:  Saltcedar species are spreading, deciduous shrubs or small trees, 1.5-6 m (5-20 ft) tall, with numerous slender branches.  The bark of young trees is smooth and reddish, but turns brown and furrowed in older trees.  The scale-like leaves are grey-green in color, 0.5-3 mm long, and overlap along the stem.  White to pink flowers are borne in spikes 2-5 cm (1-2 in) long, mostly from April through August (though they may be present year-round).  These give way to abundant hairy seeds in lance-ovoid capsules.

Spread:  Saltcedar spreads via tremendous seed production, making hundreds of thousands of tiny seeds per plant during the growing season; these are distributed by wind and water.  Buried cuttings may also sprout into new plants, and established root systems will resprout if aboveground growth is cut.  Saltcedar accumulates salt in its leaves; dropped leaves make the soil saline, inhibiting the growth of native species.  Native to Eurasia and Africa, saltcedar was imported as an ornamental in the 1800s, and is now a widespread invasive in the American southwest; thus far, it has limited presence in Oregon and Washington.

 Control:  Manual control can be achieved by removing the entire plant, including the root system; this can be quite difficult with an established tree, or if it is growing amidst desirable vegetation.  Herbicide application—either to foliage or cut stumps—has been shown to be effective.

Native Replacements:  Native willows (Salix spp.) grow well in habitats preferred by saltcedar, and provide superior habitat for birds and other wildlife.  Scouler’s willow grows best in slightly drier soil; Sitka willow prefers wet soil.