You will find Pinguicula grandiflora in Ireland and parts of Western Europe.
Though this Butterwort is only about 4 inches in diameter at the very most, it has one of the most striking flowers of the Butterwort family. Pinguicula grandiflora is a hardy species that produces delightful deep purple flowers in early Spring. Makes a brilliant display in a large shallow pot as it spreads out. This is insectivorous and you always find small flies stuck to the upper surface of the leaves. In Spring clip off old leaves to make way for flower buds and new leaf growth.
In Spring, the cycle begins by the opening of the Winter buds and the production of the first carnivorous leaves. The first leaves are followed by the flowers in Summer. New carnivorous leaves are produced during all the season. Near Autumn, or earlier, if the conditions are not optimal, the next hibernacula is revealed in the centre of the rosette. Then leaf production stops and the old leaves decay slowly. The plant, reduced now to a small hibernacula, is ready for Winter and for the next cycle. It spends the Winter as a small resting bud.
Temperate Butterworts are from the temperate climates and require a dormancy period. During dormancy the plant die back to a resting bud known as a hibernacula. Temperate Butterworts not only reproduce by seed, but also by gemmae. These gemmae, brood bodies, form around the base of the hibernacula. They look like miniature resting buds. They break of from the hibernacula very easily and are scattered around, assisting on the further propagation of the species.
The flat leaves of the Butterwort are covered in thousands of minute hairs each topped with a little glob of sticky glue. This glistens in the sun, sometimes having a rainbow effect, and this is thought to attract small flies such as gnats and fruit flies. Once caught the prey will rarely be able to come unstuck, and struggling just makes things worse. Almost immediately glands on the leaf secrete digestive juices to soften the prey. So much is produced that this can happen in a few hours. The nutrient rich fluid is then re-absorbed. Sometime the edges of the leaf curl inwards, possibly to prevent these juices escaping.
Hardiness zones 6-8, (-20°C/-5°F, -10°C/15°F) in Winter. Can tolerate temperatures as low as -10°F. Because they require 4-5 months of cold temperatures for a Winter dormancy, you can leave them outside. If the temperature in Winter is below 5 °C they can be kept outside all year round. Protect them from dry freezing wind during deep freezes by covering the plant with a black plastic. Uncover the plant when the deep freeze and dry freezing wind is over. Otherwise put them in the refrigerator over Winter. They require cool Summers with air temparatures not exceeding 25 °C for longer periods.
Best grown outdoors as a container or potted plant. Because of their specific soil requirement, avoid planting them in the ground. Excellent for the deck or patio. You may also grow them in a pond or a home bog garden. Requires nutrient-free soil that provides good drainage. Use a planting medium composed of 3 parts peat moss and 1 part sand.
Optimal Summer growing conditions are good air humidity, cool temperature and UV lights. If the Summer growing conditions are not optimal, the plants will form very weak hibernacula which easily rot. Grow these carnivorous plants outside in partial sun, but not full shade. Morning sun is best. Avoid direct sunlight during the afternoons.
Use rain water poured on the top of the pot taking care not to wet the rosette. When this Pinguicula begins to produce its non-carnivorous leaves, from October to April, It is important to let the media drying completely but with an atmospheric humidity of about 80%. You can do that by putting a saucer full of water under the pot, evaporation will do the rest. Inversely, when the plant begins to produce in early Spring its carnivorous leaves, you have to progressively start watering again the pot. Let the media drying slightly between two watering.