BUTTERWORTS (PINGUICULA)
This attractive genus grows throughout the northern hemisphere and into Central and South America. Butterworts or pings, as they are often called, generally have rosettes of flat leaves with upturned margins. The leaves are covered with sticky hairs that catch small insects. Different butterwort species are distinguished for the most part by their flowers, which are striking. They are divided into temperate, subtropical and tropical butterworts.
TROPICAL OR MEXICAN BUTTERWORTS
Most butterworts are from Mexico and the group is popular due to their suitability as sunny windowsill plants and the fact that most have wonderful flowers, often quite large, for long periods of time. Their sticky, carnivorous leaves lure, trap, and digest insects in order to supplement the poor mineral nutrition available in their environment. Most tropical butterworts undergo a drought period in late winter or spring, when the carnivorous leaves and most roots die away and are replaced by a crown of small succulent non-carnivorous leaves.
Water: Most Mexican butterworts are adapted to areas that receive very little water for half the year. During the growing season, when the plants are producing carnivorous leaves, plants may be watered by the tray method - letting the pot sit constantly in ½ inch or so of water. During the dry season, when plants have succulent leaves, it is best to keep the saucer or tray dry and the medium only damp. When sticky leaves return, keep some distilled or reverse osmosis water in the saucer or tray. East Bay water is fine.
Growing Media: We use two recipes at the UC Botanical Garden for Mexican pings:
(A) One part perlite, one part horticultural grade sand, one part peat.
(B) One part turface, one part perlite, one part horticultural pumice, and one part horticultural grade sand. Either seem to work well.
Humidity: Fairly high, especially during the active growing season. Tropical butterworts can be grown on sunny windowsills or in warm greenhouses. Many species take a significant portion of their water requirements from humidity in the air.
Pot Size: Mexican Pinguicula do not have deep roots and do not need large pots. Pots should be larger than the diameter of the plant.
Feeding: Feeding tropical pings will encourage growth and division. Plants can be fertilized monthly by lightly misting the leaves with ¼ strength orchid fertilizer. Do not fertilize the soil. Alternatively, freeze dried bloodworms, available at many pet stores, can be finely crumbled and spread lightly on the leaves. If your pings are catching plenty of gnats on the own, fertilizing is probably unnecessary.