Tamarix ramosissimus x chinensis L.

by , Native Plants Class
Common names: deciduous tamarisk, saltcedar
Family: Tamaricaceae
Synonomy: Tamarix africana Poir,. Tamarix aralensis Bunge, Tamarix canariensis Willd., Tamarix chinensis Lour. (synonomy: Tamarix pentandra Pallas), Tamarix dioica Roxb. Ex Roth, Tamarix gallica L., Tamarix parviflora DC. (synonomy: Tamarix tetrandra auct. non Pallas), Tamarix ramosissima Ledeb., Tamarix tetragyna C. Ehrenb.
Recent genetic testing indicates that the most common tamarisk throughout western North America is a hybrid of T. chinensis x T. ramosissima (4). Other hybrids also exist, contributing to the difficulty of separating invasive tamarisk species based on morphology. Previous taxonomic studies have used microscopic characteristics such as where the filament is inserted into the nectary disk to separate the different species, and field identification is difficult (1).
Etymology: The common name “saltcedar” derives from the plant’s ability to tolerate high salinity and to secrete salt from its leaves. The feathery branches are thought to resemble juniper or “cedar” (2).

Identification
Growth form: Tamarisk is a shrub or small tree to 5 m in height.
Roots: Root development varies based on water availability. In saturated soils the taproot grows laterally and secondary roots are sent out to the capillary fringe. In drier soils, the taproot grows down to the water table with the secondary branches growing outward (10).
Stem: Stems arise from a red-brown woody crown in shrubby forms and a grey trunk in tree forms. Young branches are long, slender, and reddish in color, with leaf scars very noticeable during dormancy. Basal shoots in contact with moist soil can vegetatively reproduce (10).
Leaves: Leaves are alternate, small and scale-like with a bluish-green coloring.
Inflorescence/flowers: Inflorescences are narrow 2-5 cm long racemes grouped in drooping terminal clusters. Flowers are regular and very small (15 mm long) deep pink to nearly white blooms, with 4 or 5 petals, 4 or 5 sepals, 4 or more stamens and 3-5 styles. The ovary is superior and one-celled.
Fruit: Seeds are somewhat cylindrical with a diameter of about 0.17 mm and length of about 0.45 mm. Attached to the apex of the seed coat are slender unicellular hairs about 2.12 mm long (10). Seeds are small and weigh about 0.0001 g; one mature plant may produce 0.5 to one million seeds per season (2).
Similar species: Tamarix aphylla (L.) Karst. is an evergreen tree (to 20 m) with sheathing leaves and sessile flowers. Deciduous tamarisk species can be easily distinguished from T. aphylla by their shorter stature, non-sheathing leaves and pedicellate flowers.

Ecology
Life history: Tamarisk is a perennial. Its lifespan in the United States is unknown.
Native/introduced: Introduced from Eurasia. A noxious weed in many western states.
Photosynthetic pathway:
Phenology: In northern Arizona, tamarisk flowers from March to August (3). Seeds are disseminated throughout the growing season (10).
Distribution: Deciduous tamarisk is now found throughout the North American West, south into Mexico, north to Montana, and east to Kansas. There are small populations established in Massachusetts, Indiana and Missouri (11). In Arizona tamarisk is found in all counties along streams and drainages below 6000 feet (9).

Uses
Wildlife: Tamarisk is used by introduced bees as a nectar source (3). It forms extensive thickets along rivers and lakes and has been shown to reduce the local biodiversity of flora and fauna (5,6,7). Some stands are designated as critical habitat for the Southwest Willow Flycatcher, an endangered bird that now nests in tamarisk thickets.
Human: Tamarisk was originally introduced as an ornamental and for erosion control (2). It is no longer planted because of its ability to invade natural habitats, and many government agencies now have tamarisk eradication programs.

References
1. Baum, B.R. 1978. The Genus Tamarix. Israel Academy of Sciences and Humanities: Jerusalem. 187 pp.

2. Brock, John H. 1994. Tamarix spp. (salt cedar), an invasive exotic woody plant in arid and semi-arid riparian habitats of western USA. In Ecology and Management of Invasive Riverside Plants, L.C. de Waal, L.E. Child, P.M. Wade and J.H. Brock, eds. John Wiley and Sons, Ltd: London. Pp. 27-44.

3. Epple, A.O. 1995. A Field Guide to the Plants of Arizona. Falcon Press: Helena, MT. 347 pp.

4. Gaskin, J.F. and B.A. Schaal. 2002. Hybrid Tamarix widespread in U.S. invasion and undetected in native Asian range. Proceedings of the National Academy of Science 99(17): 11256-11259.

5. Hoddenbach, G. 1989. Tamarix control. Pp. 116-125 in Tamarisk Control in Southwestern United States. Kunzmann, Johnson and Bennett, Eds. Special Report No. 9, Cooperative National Park Resources Study Unit: Tucson, AZ.

6. Hunter, William C., Robert D. Ohmart and Bertin W. Anderson. 1990. Use of exotic saltcedar (Tamarix chinensis) by birds in arid riparian systems. The Condor 90: 113-123.

7. Jakle, M.D. and T.A. Katz. 1985. Herpetofaunal use of four habitats on the middle Gila River drainage, Arizona. Proceedings, First North American Riparian Conference, Tucson, Arizona, pp. 355-358.

8. Kearney, T.H. and R.H. Peebles. 1964. Arizona Flora. University of California Press: Berkeley, CA. 1085 pp.

9. McDougall, W.B. 1973. Seed Plants of Northern Arizona. Museum of Northern Arizona: Flagstaff, AZ. 594 pp.

10. Merkel, Daniel L. and Harold H. Hopkins. 1957. Life history of salt cedar (Tamarix gallica L.). Transactions of the Kansas Academy of Science 60(4): 360-369.

11. USDA. February 2002. Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory, online Fire Effects Information System. www.fs.fed.us/database/feis.