Tamarix ramosissima Seeds | Salt Cedar

Salt Cedar (Tamarix ramosissima) with fine grey-green foliage and dense pink flower plumes in late summer — Salt Cedar (*Tamarix ramosissima*): Tamaricaceae, a deep-rooted Eurasian shrub that became one of the costliest riparian invaders in North America.

LATIN NAME: Tamarix ramosissima

COMMON NAME: Salt Cedar

Plant Profile

Salt cedar is a shrub or small tree of two to six metres, rarely more, with slender, reddish brown stems and a crown that stays open and somewhat ragged. The leaves are even smaller than those of the Chinese tamarisk, scale-like and barely a millimetre or two long, grey-green and closely appressed to the stem, so that the whole plant reads as a mass of fine, feathery texture rather than as foliage. The bark on old trunks is dark and furrowed, and the wood is close-grained and hard for its size.

The flowering is the season when the plant is unmistakable. From midsummer into early autumn it produces dense, tapered plumes of pink to pale rose flowers almost entirely on the current season’s growth, and a well-grown bush can be covered for six weeks. Each flower is tiny, with five petals and five stamens, and the capsules that follow release seed with a hairy tuft, adapted to be carried by wind and water. The native range runs from southeastern Europe through the Caucasus and Central Asia to northwestern China and Mongolia, where it grows along rivers, in saline depressions and on lake margins. In those landscapes it is a normal component of the flora, held in check by flooding, ice scour and competition. Elsewhere, freed from those limits, it behaves very differently.

Science & Biotechnology

Salt cedar is one of the most studied invasive plants in North America, and the research is unusually clear about why it succeeds. It sends roots down to the capillary fringe above the water table, and it can draw on groundwater at depths that exclude willow and cottonwood seedlings, which need a surface supply. Once established it transpires heavily, and stands have been measured using more water than the native vegetation they replace. It also loads salt into the surface soil, through leaf litter and through glands that excrete chloride and sodium, creating conditions that suppress the germination of its competitors.

The plant changes fire regimes, because its stands carry dry fuel and regrow quickly from the root crown after burning, and it hybridises freely with Tamarix chinensis where the two meet. That hybridisation complicated the biological control programme, since the beetle Diorhabda carinulata, released across the western states, defoliates the plants in cycles and has produced patchy rather than decisive results. Recent work uses remote sensing to map defoliation and recovery, and combines it with hydrological modelling to predict where removal will actually restore streamflow. The consensus is that salt cedar is a symptom of altered rivers as much as a cause, and that clearing it without restoring flow and flooding regimes rarely brings back the native woodland.

Uses & Benefits

In its native range the plant has real value. It is planted as a windbreak and sand-binding shrub across the dry belt from Iran to Inner Mongolia, its flexible stems are used for basketry, and its wood is burned for fuel. The galls produced on the twigs by sap-sucking insects are rich in tannin and have been used in dyeing and in traditional medicine, and the flowers are a source of honeydew. None of this outweighs its behaviour where it is not native, and several states in the western United States restrict its sale and planting, particularly near waterways.

For a gardener outside the invaded regions, salt cedar remains a useful subject for dry, saline and windswept sites. It is fast, extremely tough, and gives late summer colour when most shrubs have finished. It should be sited away from natural watercourses and irrigation infrastructure, because its roots will find both. In cold-winter climates the top may die back, but it regrows from the base and flowers on the new wood the same season. It responds well to coppicing, which keeps it dense and controls its size, and it tolerates pruning at almost any time of year.

Growing from Seed

The seed is minute and short-lived, viable for weeks rather than months, so it must be sown fresh on a saturated surface and left uncovered to the light. Use a fine, firmed mix in a tray, water it until it shines, scatter the seed thinly, and cover with glass to hold humidity. Germination can start within days. The seedlings are fragile for their first month and must never dry out; mist them from above rather than watering heavily, which would wash them out.

Cuttings are the practical route for most growers, and hardwood pieces taken in winter root easily in a warm, humid case. Once rooted, pot them on into a gritty mix and grow them in full sun. Plant out into any well-drained soil, including sand and gravel, and water only through the first summer. Space the plants generously if a screen is wanted, since the habit is wide and loose. Cut back hard in late winter every few years to keep the framework young and the flowering vigorous.

Our Take

Salt cedar is a plant to grow with your eyes open: superb for dry ground and late colour, but a liability beside a river in the wrong part of the world. In the right place it asks for nothing but sun.

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