Silphium

Silphium laciniatum, better known as the compass plant, is a towering perennial, with flowers resembling dark-centred yellow daisies that reach a height of 3 metres (10 feet). It gets its name from the ability of its leaves to orient themselves, based on the rising sun, on a North-South axis. A true icon of the wet and fertile prairies of North America, it can live for a hundred years. It shows its striking silhouette on the horizon, adorned with insects and birds, at the edges of wild gardens.

Silphium perfoliatum is also a very tall perennial with sun-loving yellow flower heads. This large perennial plant, native to the plains of central-eastern North America, has a robust stump from which tall, straight, quadrangular stems over 2 metres (7 feet) high emerge in spring, unaffected by the wind. The matte green leaves cover the base of the stems and often retain rainwater, earning it the nickname "bird bath". The flowers, resembling large golden yellow daisies with a diameter of 7cm (3in), bloom in summer at the ends of branching stems.

Silphiums are easy to grow in open, sunny locations, in rich, moist to wet, even chalky, but well-drained soil. Note that Silphium laciniatum is more sensitive to wet soil in winter than Silphium perfoliatum.