Subspecies
subsp. wulfenii
This large upright shrub grows to 1 m (3ft) tall with thick succulent stems that are topped with silver grey linear leaves.  During spring the plant produces both yellow-green cyathia and nectar glands.

Cultivars
'Blue Hills'
This upright shrub has a slender stems topped with slender blue grey leaves up to 800 mm (44in) tall and produces large flower heads with dark-eyed yellow-green bracts. Care should be taken as the milky sap can cause skin or eye irritations.

'Humpty Dumpty'
This variation of Wulfenii is a smaller up to 450 mm (18in) tall and wide with numerous slender greyish stems that form an open rounded habit with blue-green foliage.  From late winter to spring it produces terminal cylindrical flower heads with tiny yellow flowers that are accompanied by pale green bracts.  
This shrub prefers an open sunny position in well-drained soils and is suitable for patio pots or planter boxes. It grows in USDA zone 7-11 and in warmer regions the flowers of may appear from spring to autumn.

'Joyce's Giant'
This variation of Wulfenii forms an open rounded habit up to 1 m (3ft) tall by 1.5m (5ft) wide with multiple slender stems that have grey green foliage.  During spring it produces large terminal cylindrical flower heads that consist of tiny yellow flowers with yellow-green bracts.

'Lambrook Gold'
This variation of Wulfenii is the most commonly cultivated, growing 1 m (3ft) tall and wide.  During spring it produces pure yellow flowers in cylindrical cymes that contrast with the grey foliage for an excellent display. 
It grows in most well drained moderately fertile soils in an open sunny position and is hardy to zone 7. It was bred by the plantswoman Margery Fish at east Lambrook Manor.

'Sibthorpill'
This variation of Wulfenii has upright slender purplish branched stems to 1 m (3ft) tall and topped with narrow grey-green foliage.  From spring to summer it produces large terminal cylindrical clusters with bright yellow-green bracts. It prefers an open sunny position in well-drained soil and is pH adaptable.  
It is planted in cottage gardens along borders or may be used in patio pots or planter boxes.  This plant is hardy to zone 7 and is moderately drought tolerant.

'Silver Swan'
This upright bushy shrub produces leaves and cyathia that are variegated with creamy white markings along the margins. It is planted in perennial borders for foliage contrast and should be cut back after flowering every two to three years to encourage a bushy habit.