Aggressive Ornamentals

Saltcedar (Tamarix ramosissima, T. parviflora)

Saltcedar, a shrub to small tree, is native to Northern Europe and temperate and tropical Asia. It was introduced to the western United States as an ornamental in the 1800's. Saltcedar is now established or known in many desert regions of the western US, including Washington, Idaho and Montana. Tamarix ramosissima is sold as an ornamental under the name "Pink Cascade" Tamarisk in some BC nurseries. A related species, Tamarix parviflora, is listed as rarely found in BC. Both are aggressive ornamentals that should be prevented from escaping cultivation.

Biology 

Saltcedar is a spreading, deciduous shrub or small tree. It grows from 1.5 to 7.0 metres tall forming dense thickets. Branches are numerous; slender, with small, alternate, greyish-green overlapping or scale-like leaves. Bark of young branches is smooth and reddish-brown. Pale pink to white flowers bloom in dense masses on 1 cm. long spikes at branch tips from March to September. Flower petals and sepals occur in fours and fives.

Reproduction 

Saltcedar reproduces from seed and by re-sprouting from roots and underground stems. A single mature plant can produce thousands of seeds. Throughout the growing season tiny, hairy seeds are dispersed widely by wind and water. Seeds are capable of germination within 24 hours. Initially seedlings are slow growing but once established they can grow up to 0.3 metres per month. Resprouting is usually initiated when the top portion of the plant is damaged or removed. Saltcedar can also reproduce from cuttings buried in moist soil.

Habitat 

Saltcedar is adaptable and tolerant to a wide variety of environmental conditions. It requires extended periods of soil moisture for successful establishment, appearing to grow best in saline soils while tolerating alkali conditions. It is found in streams, waterways, on banks of waterbodies, bottomlands, moist rangelands and pastures. In the southwest US, saltcedar is principally found in deserts and desert grasslands.

Concern 

Saltcedar is a massive consumer of water. Its long taproot penetrates the soil to deep water tables and interferes with natural aquatic systems. Mature saltcedar stems and leaves excrete salt, forming an above and below surface crust which inhibits other plants. These characteristics make it an aggressive colonizer that will replace willows, cottonwoods and other riparian vegetation. Saltcedar's enormous consumption of water stresses native plants by lowering ground water levels thereby drying up springs and marshes. Its massive rooting system can clog watercourses resulting in flooding. Saltcedar can provide cover for some wildlife species but its foliage and flowers contribute little in the way of food value for native wildlife consumption. It is listed as a legislated noxious weed in 6 US states. Despite decades of cultivation in British Columbia it is not known to have caused a concern in the province to date. Landscapers are encouraged to plant alternate vegetation and to ensure existing plantings do not escape.

	Flowers
	Flowering Branch

Photos courtesy James Manhart, TAMU-BWG Digital Library

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