The butterworts (pinguicula) may be the least exciting of the insectivorous plants when it comes to their leaves but they are efficient insect eaters and they do have the most beautiful flowers. The viola-like flowers are usually in shades of pink or mauve. Pinguicula grandiflora is native to the UK and Ireland but most species are from Central and South America. They form rosettes of flat leaves, covered in glands that give the leaves a waxy feel – hence butterwort. These glands, which produce the digestive enzymes as well as the stickiness to catch small insects – rather like fly paper – have antibacterial properties too, which are thought to help reduce the prey from rotting before being digested and absorbed and the leaves have been used in local medicine to help heal wounds.
One of the easiest to grow, which is apparently used commercially in greenhouses to reduce whitefly and fungus gnat populations, is P. moranensis from Mexico which is one of the centres of diversification in the genus. It is a large plant with rosettes 15cm apart and large, pretty flowers. In Ireland and the UK the most common species is P. grandiflora which has violet flowers in spring and spends winter as a resting bud known (as in drosera) as a hibernacula – nice word! It is a hardy plant that needs a wet, acid soil although some species tolerate alkaline soils and P. vulgaris is found in fens which are often alkaline even though the peaty soils are wet and low in nutrients.
They are small, neat plants that can be grown on a sunny windowsill and can help keep down insects in the house but they can also be grown in a cold greenhouse or outside in the garden in pots or in a pond or bog garden.
I will just end this little series by saying that the only reason I have not mentioned the Venus fly trap is because I do not have photos here and I do not have one at the moment – no other reason!