Cytisus scoparius

Cytisus scoparius, the common broom or Scotch broom, syn. Sarothamnus scoparius, is a perennial leguminous shrub native to western and central Europe. In Britain and Ireland, the standard name is broom, but this name is also used generically for other related species (see broom), and the term common broom is sometimes used for clarification. In other English-speaking countries, the most prevalent common name is Scotch broom (or Scot's broom); English broom is also occasionally used.

Classification

There are two subspecies of Cytisus scoparius:

Description

Plants of Cytisus scoparius typically grow to 1–3 m (3.3–9.8 ft) tall, rarely to 4 m (13 ft), with main stems up to 5 cm (2.0 in)thick, rarely 10 cm (3.9 in). The shrubs have green shoots with small deciduous trifoliate leaves 5–15 mm long, and in spring and summer is covered in profuse golden yellow flowers 20–30 mm from top to bottom and 15–20 mm wide. Flowering occurs after 50-80 growing degree days. In late summer, its legumes (seed pods) mature black, 2–3 cm long, 8 mm broad and 2–3 mm thick; they burst open, often with an audible crack, forcibly throwing seed from the parent plant. This is the hardiest species of broom, tolerating temperatures down to about −25 °C (−13 °F).C. scoparius contains toxic alkaloids that depress the heart and nervous system.