Scotch Broom

Plants of C. scoparius typically grow to 1–3 metres (3+1⁄2–10 feet) tall, rarely to 4 m (13 ft), with main stems up to 5 centimetres (2 inches) thick, rarely 10 cm (4 in). Stems are ridged and green. The shrubs have green shoots with small deciduous trifoliate leaves 5–15 millimetres (1⁄4–5⁄8 in) long, and in spring and summer are covered in profuse golden yellow flowers 20–30 mm (3⁄4–1+1⁄8 in) from top to bottom and 15–20 mm wide. Flowering occurs after 50–80 growing degree-days. The seed pods have long hairs only along their seams. In late summer, its legumes (seed pods) mature black, 2–3 cm (3⁄4–1+1⁄4 in) long, 8 mm (3⁄8 in) broad and 2–3 mm thick; they burst open, often with an audible crack, forcibly throwing seed from the parent plant. This species is adapted to Mediterranean and coastal climates, and its range is limited by cold winter temperatures. It also adapts to windy oceanic climates. The seeds, seedlings, and young shoots are sensitive to frost; adult plants are hardier, and branches affected by freezing temperatures regenerate quickly. C. scoparius contains toxic alkaloids that depress the heart and nervous system. As a legume, this shrub can fix nitrogen in the soil through a symbiotic relationship with Rhizobium bacteria.

Phytochemicals. One of the main alkaloids of this plant is cytisine. …

Cytisus scoparius is native to western and central Europe, being common in Great Britain and Republic of Ireland. It is found in sunny sites, usually on dry, sandy soils at low altitudes, tolerating very acidic soil conditions. Outside of its native range, it is an ecologically destructive colonizing invasive species in grassland, shrub and woodland, and other habitats.

Broom contains scoparin, which is a diuretic. The plant also is used as a cathartic and as a cardiac stimulant, which is credited to the presence of sparteine. A decoction or infusion of broom can be used to treat dropsy due to its diuretic action. An ointment can be made from the flowers to treat gout. Oxysparteine, produced from the action of acid on the sparteine, is useful as a cardiac stimulant and has the advantage over digoxin that it does not accumulate in the body. A medicinal beer was brewed from this herb, called broom ale, as a remedy for dropsy.

Cytisus scoparius is widely cultivated as an ornamental plant, with several cultivars selected for variation in flower colour, including "Moonlight" with deep yellow flowers, "Andreanus" and "Firefly" with dark orange-red flowers, and growth habit, including "Pendula" with pendulous branchlets.

In Welsh mythology, Blodeuwedd is the name of a woman made from the flowers of broom, meadowsweet (Filipendula ulmaria) and the oak by Math fab Mathonwy and Gwydion to be the wife of Lleu Llaw Gyffes. Her story is part of the Fourth Branch of the Mabinogi, the tale of Math son of Mathonwy. Broom was considered a sign of plenty when it bore many flowers. However a traditional rhyme from Sussex warns: "Sweep the house with blossomed broom in May/sweep the head of the household away." Broom was also used in a decorated bundle of broom at weddings in place of rosemary when that was scarce, and its strong smell was said to be able to tame wild horses and dogs. In Italy, the shrub was burnt with the intent of stopping witches.

Royal symbols. The name of the House of Plantagenet, rulers of England in the Middle Ages, may have been derived from common broom, which was then known as planta genista in Latin. The plant was used as a heraldic badge by Geoffrey V of Anjou and five Plantagenet kings of England as a royal emblem. The broomscod, or seed-pod, was the personal emblem of Charles VI of France.