French tamarisk, or Tamarix gallica, is a deciduous shrub or small tree growing up to 4.8 meters in height.
The plant has many slender branches and small alternate, scale-like leaves that are grey-green and overlap along the stem.
Tamarix gallica is identified by its pinkish-purple to white flowers with feather-like spikes.
Scientific Classification
- Domain: Eukaryota
- Kingdom: Plantae
- Phylum: Spermatophyta
- Subphylum: Angiospermae
- Class: Dicotyledonae
- Order: Tamaricales
- Family: Tamaricaceae
- Genus: Tamarix
- Species: Tamarix gallica
- Other Names: French tree, Manna plant, and Salt cedar
Nativity and Distribution
Tamarix gallica is native to Southern Europe and North Africa through the Middle East. The plant is also distributed in the following areas:
- Temperate Asia
- United States
Physical Appearance
- Leaves: Pale green, small and scale-like.
- Flowers: They are pale pink to white and arranged in terminal inflorescences.
- Fruits: They are small pyramid-shaped pods.
- Stem: Stems are green or white.
- Roots: Has a long tap root system.
Tamarix gallica flowers are pinkish-purple to white and measure 1.5mm to 2mm in diameter. They are arranged in spikelike racemes up to 5 cm long.
The plant’s flowers are hermaphrodites (both male and female sex organs in the same flower) and are carried on thin, feather-like spikes. The flowers bloom throughout the summer from June to August.
French tamarisk leaves are 1 to 3 mm long. They overlap each other along the stem, forming dense clusters.
Tamarix gallica stems are slender and flexible and can grow up to 4 meters tall.
The plant’s leaves are thick, succulent, rolled, small, or waxy to reduce water loss through transpiration. The leaves also have salt glands to collect and excrete soil.
Adaptive Features
- French tamarisk is a facultative phreatophyte that uses surface water and groundwater. Mature plants can survive desert heat, burning, below-freezing temperatures, drought, and flooding.
- Tamarix gallica growth is limited because plants cannot get water from the soils due to soluble salts, which hold water much more tightly than plants can extract.
- Some of the plants have salt glands that collect and excrete salts.
- The plant grows best in alkaline soil but tolerates salinity and acidity.
Life Cycle/Reproduction/Dispersal
- Life Cycle: Perennial.
- Seeds: Thousands of tiny cottony seeds contained in a small capsule.
- Climate: Thrives in moderate temperatures between 60 and 75 Fahrenheit.
- Dispersal: The seed has small hairs on the apex of the seed coat, which make it readily dispersed by wind and water.
French tamarisk reproduces by both sexual and asexual means. In sexual reproduction, the plant produces hermaphrodite flowers, which are pollinated by wind and insects.
Once pollination occurs, fertilization occurs, leading to the development of seeds contained in a capsule.
When the capsule matures, the plant’s small seeds are released. They can be dispersed through the wind and water, settle on the soil surface, and new growth begins within 24 hours of water contact.
In asexual reproduction, Tamarix gallica reproduces naturally through adventitious roots that grow on stems submerged in water or on moist soil.
Uses
- Used as an ornamental plant due to its pink flowers.
- The plant has a high salt concentration and thus can be planted on coastlines to prevent strong weeds.
- Has been used in places like Algeria to treat rheumatism and diarrhea.
Impact on the Environment
Tamarix gallica causes the following effects:
Decreasing biodiversity
In many areas, French tamarisk is considered an invasive weed. The plant reproduces through stem cuttings, making it easy to spread and crowd out native plants, thus reducing biodiversity.
High water consumption
The plant consumes water at a high rate and has a deep tap root system, thus affecting native species that rely on those water sources.
Increase in soil salinity
According to ScienceDirect, Tamarix gallica increases soil salinity by depositing salts from its leaves and stems into the soil.
The increased salt deposits left by the plant can alter soil chemistry, thus making it difficult for other native plants to grow.
Control
The following control methods will control the French tamarisk:
Physical control
Tamarix gallica can be controlled by hand pulling and digging out the young plants or small infestations.
However, you must be careful as stem cuttings may move into the water columns and sprout, thus leading to new growth.
Biological control
The Tamarisk beetle, Diorhabda carinulata, has been used as a biological control agent for the French tamarisk.
The beetles consume the foliage of the tamarisk, which weakens the plant by reducing its ability to photosynthesize.
Since its release, the beetle has defoliated thousands of acres of tamarisk in Nevada, Wyoming, Utah, and Colorado.
The Tamarisk beetle feeds on the plant’s leaves, slowly reducing its vigor. However, the plant can resprout after weeks of defoliation, so it’s advisable to defoliate it repeatedly.
The Tamarix gall wasp Andricus kollari can also manage French tamarisk populations. These insects destroy the plants by laying their eggs inside their stems.
Chemical control
The cut stump treatment method is effective for controlling Tamarix gallica.
This method involves cutting the plant close to the ground and applying herbicides such as Triclopyr Garlon 3A and Garlon 4 Ultra. This method is selective and will not harm the surrounding plants.
Other herbicides that can control the French tamarisk include Imazapyr and broad-spectrum glyphosate.
Lead Editor for Insight Weeds.