Spanish broom is a deciduous shrub native to the Mediterranean, West Asia, and North Africa. Fragrant yellow pea-like flowers cover the shoots in late spring and summer. It is cultivated for its ornamental value and is used for flavoring and essential oil extraction.
I. Appearance and Characteristics
Spartium junceum, known as Spanish broom, rush broom, or weaver’s broom, it is a species of flowering plant in the family Fabaceae and the sole species in the genus Spartium. It is closely related to the other brooms (in the genera Cytisus and Genista).
The Greek name Spartium given to the genus denotes the use of the plant for ‘cordage’. The Latin specific epithet junceum means “rush-like”, referring to the shoots, which show a passing resemblance to those of the rush genus Juncus.
Spartium junceum is a vigorous, deciduous shrub growing to 2–4 metres (7–13 feet) tall, rarely 5 m (16 ft), with main stems up to 5 centimetres (2 inches) thick, rarely 10 cm (4 in). It has thick, somewhat succulent grey-green rush-like shoots with very sparse small deciduous leaves 1 to 3 cm (1⁄2 to 1+1⁄4 in) long and up to 4 millimetres (1⁄8 in) broad.
The leaves are of little importance to the plant, with much of the photosynthesis occurring in the green shoots (a water-conserving strategy in its dry climate). The leaves fall away early. In late spring and summer shoots are covered in profuse fragrant yellow pea-like flowers 1 to 2 cm across. In late summer, the legumes (seed pods) mature black and reach 8–10 cm (3–4 in) long. They burst open, often with an audible crack, spreading seed from the parent plant.
This species is native to the Mediterranean in southern Europe, southwest Asia and northwest Africa, where it is found in sunny sites, usually on dry, sandy soils.
As an invasive species
Spartium junceum has been widely introduced into other areas, and is regarded as a noxious invasive species in places with a Mediterranean climate such as California and Oregon, Hawaii, central Chile, southeastern Australia, the Western Cape in South Africa and the Canary Islands and Azores. It was first introduced to California as an ornamental plant.
Toxicity
Few cases have been described of intoxication by the S. junceum, including accidental ingestion of different parts of the plant by children. The alkaloids found in all parts of the plant have toxic effects. They initially provoke a transitory stimulation of nicotinic cholinergic receptors followed by a persistent inhibition caused by desensitization. The sparteine has an effect on the heart, reducing its sensitivity and conductivity.
Symptoms present depending on dose, method of exposure, and time elapsed since exposure; these include irritation of the oral and pharyngeal mucosa, hypersalivation, vomiting, stomach pain and diarrhea. In severe cases, neurological symptoms (such as midriasis, headaches, delirium and convulsions) may be present, as well as hypotension, bradycardia, and coma.
II. How to Grow and Care
Sunlight
Spanish broom thrives in conditions where it can bask in full sun. It requires intense, unfiltered sunlight for robust growth and flowering. While spanish broom can endure some degree of variation in light intensity, prolonged exposure to less than optimal sunlight, such as partial shade, could result in stunted growth and reduced blooming. This hardy species possesses adaptive traits enabling it to maximize light absorption, critical for its vitality in natural, outdoor settings.
Recommended planting positions for spanish broom are in areas where it will receive unhindered sunlight, such as open fields, slopes, or south-facing garden spots. Spanish broom is not typically grown indoors due to its high light and space requirements.
Watering
Originating from the Mediterranean region, spanish broom is well-adapted to dry climates and thrives with minimal water input. This species exhibits a high drought tolerance, relying on its ability to conserve water in arid conditions. Watering should be sparse, aligning with its native habitat’s infrequent rainfall—once every two weeks suffices. Typically found in outdoor settings due to its size and growth habit, spanish broom benefits from a well-draining soil that mimics its natural rocky terrains, which prevents waterlogging and promotes healthy root development.
Fertilizing
For Spanish broom, a balanced fertilizer ensures robust growth; high nitrogen variants can stimulate dense foliage. Ideal fertilization occurs in spring, aligning with its growth spurt. Use caution to prevent root burn: apply sparingly, and follow dosage instructions. Seasonal adjustments to feeding are paramount, with minimal to no winter fertilization recommended. Practical tip: incorporate fertilizer into the soil around spanish broom, avoiding direct contact with the base to safeguard against potential damage. A periodic check is wise to adjust the regimen according to the spanish broom’s response, fostering optimal health and bloom.
Propagation
Spanish broom is a resilient legume that thrives in well-drained soil and full sun. To propagate spanish broom, sowing seeds is recommended after a treatment to break seed dormancy, such as scarification. Soak the seeds in warm water overnight before planting to enhance germination rates. Choose a sunny location and use sandy, lean soil for planting. Consistently moisten the soil, but avoid waterlogging. With patience and care, the Spanish broom will establish itself, ready to reveal its vibrant yellow flowers and refreshing aroma.
Transplanting
The ideal season to transplant Spanish broom tends to fall between late autumn and early spring (S1-S2), as the plant has a better chance to establish roots before the growing season. Choose a sunny location ideally, as spanish brooms thrive in full sunlight. While transplanting, take care to ensure the root ball is not damaged, to help the plant adapt quickly. Beware, spanish brooms can be invasive so it’s best placed where it can spread without troubling other plants.
III. Uses and Benefits
- Ornamental uses
Spanish brooms can work as an ornamental border shrub or towering hedge. It grows well in full sun and sandy soil, meaning you can grow it in coastal or Mediterranean gardens. It’s especially showy in the summer, when its yellow blooms grow in full force. It’s easy to maintain, since pests will leave this plant alone.
- Medicinal uses
In work carried out on normoglycemic mice at the Faculty of Chemistry of the University of the Republic of Uruguay, the infusion of the flowers were proven to have hypoglycemiant effects. In Turkey, the flowers have been used in traditional medicine to treat ulcers; Turkish studies from 1999 and 2000 have identified a saponin in the plant which has antiulcer properties.
- Other uses
It has traditionally been used for the production of fiber, especially for tying vines. It is also used as a hedge because of its nitrogen-fixing quality. The plant is also used as a flavoring, and for its essential oil, known as genet absolute. Its fibers have been used for cloth and it produces a yellow dye. The branches are used to make brooms.
