First Dr. Les defined some terms that may have slightly different meanings when used by different authors and speakers.  Non-indigenous:  Plants that are non-native or were not present before people moved into an area.  Naturalized: Non-indigenous plants that establish themselves in an area after being introduced.  They do not require care to grow well.  Invasive plants: Spread through the native plants and may replace them.  This includes invading natural waterways, lakes, and streams.  Cultivated plants: Require constant care and management to grow and reproduce.  Weeds:  Plants that interfere with cultivation or appreciation of natural resources.  An example of an aquatic ‘weed’ is the American Lotus.  It is endangered in the North (ex. Wisconsin), occurs sometimes in the middle states, and is considered a ‘weed’ in the South. 

Shakespeare was an expert about people and their inept romantic attempts.  Our love of aquatic plants can be compared to his romantic stories.  The story began when man learned plants could be beneficial.  Rice is the first cultivated crop plant and even now feeds a large portion of the world.  On the other hand, Egyptians introduced papyrus (a useful plant) into the delta of the Nile from central Africa.  It has formed a nightmare of impenetrable swamp.   

Infatuation is the first act of the romance.  We see something we want but really should not have.  Oftentimes the things we love turn out to be our enemies.  We love plants because of their beauty.  Shrines (botanic gardens) have been built to celebrate this beauty.   

Act Two is love is often blind and we rarely think of the future pitfalls.  One of the first, imported aquatic plants to the US was Parrot Feather.  An 1890’s reference book extols its beauty and says it is wonderful for hanging baskets and flower arrangements.  It is but is also a problem in some areas of the country.  Water Hyacinth is another imported plant creating clogged waterways in the South, Connecticut, and California, and New England.  An underwater plant, Cabomba (Fanwort), was very popular when introduced.  It is now impossible to control in the Northeast.   

Act Three is control as plants turn on their benefactors.  Herbicides are sprayed and plants are harvested or removed from waterways.  Millions of dollars are spent every year to try to control these invasive plants.  Research has shown one million invasive aquatic plants have been added to the waterways every decade for the last 150 years.  Sometimes plants were brought here by accident with other cargo rather than deliberately.  Brooklime was an accidental introduction.  Seeds and plants of Water Chestnut and Marsilea (Four-Leaf Clover) were thrown into a pond at a botanic garden with no idea that they would become a problem.  At one time people thought growing plants in their ponds would just be a stinky smelly mess.  It was not the thing to do until people saw the Victoria lilies.  Dr. Les feels that the importation of the magnificent Victoria lilies may have been the beginning of fascination with exotic aquatic plants.  We have to be careful about aquatic plant disposal and never allow any to enter natural waterways.  Studies have shown that plants escaping from cultivation have caused three fourths of the problems.  An additional twelve percent probably escaped from cultivation.  It is now illegal to import some aquatic plants.  There are 19 species that cannot be grown, sold, or cultivated.  Some of these look very similar to non-invasive plants but it is almost impossible to tell them apart.  Many have been mislabeled with the non-invasive plant name.  A common example of this is Anacharis, a popular oxygenator that has destroyed the natural ecology of many lakes in the Pacific Northwest.  

Act Four is infidelity.  Plants that were loved are now traitors.  Parrot Feather is more invasive than Purple Loosestrife, a standard of invasiveness.  Hydrilla is an aquarium and water garden plant that some thought was a tropical.  Its native range actually extends to the Artic Circle.  It is now causing problems in New England and on the west coast.  Some of these plants did not escape until water gardening became popular in the region.  Not only do they affect the ecology of waterways but also the surrounding wildlife.  Giant Salvinia is nasty.  It appears near sites where it is sold or cultivated.  Azolla, a floating plant that looks like little Christmas trees, has many names and is also invasive. 

Act Five is animosity.  We eventually realize something is drastically wrong with the relationship when all efforts to control it are futile.  We now have irreconcilable differences and look for revenge.  Now we have to accept the consequences.  But there is hope.  By using the large number of native plants, we can avoid adding to the problem and still enjoy water gardening.  There are actually more native species than those that have been imported.  Also by knowing that these plants may cause problems, we can be careful about where they are planted and how we dispose of them.