Pinguicula or Butterworts can be split into three major care groups: Mexican / Tropical Butterworts, North American Butterworts and European Butterworts. None of the Butterworts like full sun, but they don’t mind it bright.
The Mexican species and hybrids (Pinguicula x wesser, Pinguicula laueana)make excellent house plants for a north or east facing windowsill, or in the greenhouse as biological control for whitefly if they are tucked beneath other plants to screen from the sun. Grow in pots and saucers.
The European species (Pinguicula grandiflora, Pinguicula vulgaris) are best grown either outside or in a cold greenhouse. They can be grown as an alpine on tufa rock.
North American species such as Pinguicula primuliflora, Pinguicula luscitanica do well in a frost free house, though not too warm. Grow in a water tray or use pots and saucers.
Butterworts are not so fussed about whether the water is soft – they will tolerate lime. Keep The European and N. American species in 1-3cm water all year -slightly less over winter. Mexican species will die back to a non-carnivorous winter rosette, when they can be kept much drier – a little damping occasionally. Start increasing the water in spring when small white adventitious roots start to appear and new carnivorous leaves start to grow.
Butterworts are very good at catching their own small flies -fungus gnats or whitefly. Mexican species can be given a dilute acidic fertiliser for epiphytes (1/4 strength) about once a month during the carnivorous growing season. Only use it on the leaves, not the flowers. Other species won’t mind being fed occasionally, but we never do.
Mexican species will need to be much drier over winter. Grow in frost free conditions. If kept on a windowsill over winter, they may well keep growing and flowering over along period, and not produce this winter rosette. Take care that the crown doesn’t rot particularly just as it is coming back into growth.
European species will form a winter resting bud. Remove dead leaves and keep damp either outside or in a cold greenhouse.
North American species are best in a greenhouse with some frost protection. Keep wet ,but they can rot easily
Use sand, peat and vermiculite in equal quantities. European Pinguicula can be grown in 3:1Peat: sand.
Pinguicula grandiflora will produce little buds called gemmae that can be taken off and potted up very easily. Mexican butterworts can be propagated by taking some of the winter leaves, just as they about to come into growth, and laying them on a tray of vermiculite. Keep warm and humid, and they will soon root.
Pinguicula primulifora produces tiny plantlets at the ends of its leaves. These can be pressed gently into compost to root.