Common Broom, Retama negra

Cytisus scoparius typically grows to 1–3 m tall. 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. 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. Cytisus scoparius contains toxic alkaloids that depress the heart and nervous system.