Aldrovanda vesiculosa, AKA waterwheel plant is a rootless, aquatic carnivorous plant.  They originate from Africa, Australia, Asia, and Europe.  However, the majority of the natural population in the historical sites are gone.  Some are preserved only in cultivation and/or in introduced artificial sites all over the world.  

Aldrovanda is known for being notoriously difficult to grow.  However, when the conditions meet, it grows rapidly in a remarkable speed.  Aldrovanda requires humic acid, carbon dioxide, and other trace elements.  It is recommended to include companion aquatic plants such as Typha (cattail) and Nymphaea (waterlily).  These companion plants naturally release chemicals that are thought to be beneficial to the growth of Aldrovanda.

Aldrovanda vesiculosa var. vesiculosa is a cold temperate plant.  It requires full sun during the growing season.  As the weather gets colder, it will form turions (winter buds). The traps and stolons will rot away.  You can store the turions in your refrigerator during the winter months, or leave them outside.  Some growers say that the turions can be completely frozen in a block of ice, but start growing as the ice melt when the spring arrives.  

There is a great book on Aldrovanda written by Dr. Adam Cross.  If you are interested in growing Aldrovanda, this book is a must have!

During the winter to spring months, we may ship them in the form of turions. During the growing seasons, the length will be 1-3 inches long/plant. A single order includes one thread or one turion depending on the season.