Hypericum
St John's wort
Family Hypericaceae
Approximately 300 or more species (depending on authority); grown as ornamentals amongst other shrubs in a rock garden, as a border to a bed, or occasionally massed to cover the ground in the shade of trees.
Deciduous and evergreen, herbs or shrubs, most are low growing, mainly from temperate parts of northern hemisphere. Cup shaped yellow flowers, occur over long periods.
They tolerate both drought and wet periods; but prefer constant soil moisture. They like sun or semi shade; but some grow in heavier shade.
Generally hardy and easy to grow, reasonably fast growing. Respond well to feeding and watering when putting on growth, and like to be heavily pruned in late winter. Few pest or disease problems.
Propagated by cuttings any time of year, but most commonly in autumn.
Many species that are normally evergreen can become fully deciduous at low temperatures. At temperatures below minus 5 Celsius, serious tissue damage may occur.
Cultivars
H. Androseamum –semi evergreen shrub to 1m with white underleaves, bright yellow flowers and red to black berries.
H. calycinum -30cm X 1m, evergreen, bright yellow flowers 7cm diameter, very hardy.
H. gracilis -30cm X 60cm. Deep golden flowers 35mm diameter.
H. leschenaultii -2 X 1.5m, 7cm diameter rich yellow flowers.
H. X moseranum “Tricolor” -a hybrid to 0.7m tall; leaves variegated green with cream and red edge; yellow-brownish flowers in late summer.
H. olympicum – small upright or decumbent subshrub, with very small leaves and large bright yellow flowers.
H. palatum ‘Sungold’ -60cm X 1m golden yellow flowers 5-7cm diameter.
Many other named hybrids and species cultivars are also grown.