Utricularia or Bladderworts are found all over the world and can be divided into three types:
1. Terrestrial (U. sandersonii, U. bisquamata) Terrestrials are best grown in water trays, pots, and saucers. However, they are also very good at colonising if you wish to plant several plants in one container. Grow in a frost-free greenhouse or windowsill.
2. Epiphytic (U. reniformis, U. longifolia, U. alpina) Epiphytes are ideal for a terrarium and can grow well with orchids, liking fairly humid conditions. Best in pots or water plant baskets. They do like bright conditions.
3. Aquatic (U. vulgaris, U. macrorhizza). The aquatic one needs a pond – preferably on the acidic side.
Keep terrestrial bladderworts in water all year round, though they do like a bit of fluctuation in the water level. Epiphytic plants do not want to stand in much water; a cm depth will be fine. They will also appreciate some humidity and will get that if grown in a terrarium. They grow well with Nepenthes.
The best way to feed them is to flood the pot with water containing Daphnia and other microscopic organisms from a pond or water butt. You can also mist with weak epiphytic orchid fertiliser.
In winter, keep terrestrial species frost-free (though many will survive a light frost) and damp. Aquatics will form a resting bud and drop to the bottom of the pond. If you think you may lose it, take it out first, but don’t keep hardy ones too warm. Epiphytes may lose some of their leaves -keep cleaned off. Some will be ok frost-free, but others will need it warmer.
Use sand and peat in equal quantities for terrestrials. Epiphytes will appreciate the addition of sphagnum moss, and they do exceptionally well if allowed to grow through live sphagnum at the top of the pot.
Propagate most Utricularia every 2-3 years to keep the colony fresh. This involves taking a small piece and putting it in the centre of a new pot. With larger species, such as U. reniformis, take a part of the stolon and pot it up.