WATER LETTUCE IS A REAL PISTIA

Oh water lettuce.

You innocent unassuming looking little plant.

     Walk into any water garden supplier and ask for an easy to keep, good for beginners aquatic plant. You will likely have water lettuce suggested to you. Water lettuce is available at just about every aquatic plant vendor out there, and you can even get it shipped to you from online aquatic plant vendors. Some people also call it water cabbage, and it’s scientific name is Pistia, …Pistia stratiotes to be exact.water lettuce pistia new jersey

     This is a real interesting plant, and maybe it is not a plant for “beginners” after all. This plant has some history. This plant is kind of a bad child in the aquatic plant world; with a seedy past (really, it reproduces via seed). Water lettuce is, illegal!

     It’s true, run for it. There are parts of this country where you cannot cross state lines with this plant or keep it in your backyard pond. Water lettuce, in some states, is considered a Class II prohibited Plant. If you are caught with water lettuce, here is officially what happens:

     “The department is authorized to issue a written notice of violation, and issue instructions as to the manner and time in which the violation shall be rectified.”

     That’s heavy. On the lighter side water lettuce is popularly known as a floating variety of aquatic plant, and sold that way. They are cheerful looking little plants resembling an open head of lettuce. The light green, thick leaves have a short coarse hair type of covering and ridges. They are inexpensive and sold by the head for large pieces or in groups. They are free floating plants inside of your pond, but they also work as a semi rooted plant and grow nicely in very shallow slow moving waters in a stream or shallow area of your pond. Be careful when using them with pond skimmers because they float into skimmers and can cause clogging, which will cause pump burn out!

     Experts disagree as to whether water lettuce is a native North American plant but it was found here in the U.S. from Florida to Lake George, NY as early as 1765. It is found extensively in South America.  It is native elsewhere around the world too, where in Africa it is one of the favorite food sources of the Hippo. Closer to home it is a favorite food source of the Florida Manatee, and there is plenty of it down Florida way. However it is not a food source for humans and would produce terrible intense burning to the lips, tongue, and mouth if one attempted to eat it raw. If one attempted to swallow water lettuce after the intense pain and burning of chewing it, then please post it to Youtube for us all to watch ya dummy!water lettuce new jersey

     In 1765 when cataloguing Pistia stratiotes, William Bartram a famous American naturalist and explorer, noted that water lettuce could be found clogging waterways to the point of not allowing passage of even small boats. And that very issue continues today, which is why its pretty understandable that water lettuce is not allowed in some areas. The growth of Pistia can be uncontrollable, ponds and lakes can easily be covered from shore to shore, unrecognizable as a body of water.

     Most backyard pond keepers use water lettuce as a way to control nutrient levels in their pond water and to provide some shady cover for their ponds. The thick root systems of water lettuce grow long below the surface of the water sucking up nutrients from your pond water. Water lettuce roots also offer spawning ground for fish and frogs, and a source of food to nibble on. The leaves on top make for a landing spot for dragonflies and a place for frogs to hang out. Water lettuce likes a lot of sun, but not necessarily full sun.

     In the backyard water garden they easily propagate, and need to be thinned frequently. Pistia reproduces by seed and by “mother” plants growing “daughter” plants that are attached to each other, sometimes forming large mats. It is not a cold hardy plant and will wilt and die in colder climates and should be removed from your water garden at first frost. Water lettuce makes one of the best container plants and micro pond plants out there. They even make for great table top water garden plants, or center piece displays.

     Water lettuce is indeed a great beginner plant for the beginning water gardener and yet a challenge for the world’s greatest botanists. It’ll get ya in legal trouble and get ya out of water quality trouble at the same time. It goes by the name lettuce but will melt your face off if you try to eat it. Nobody really knows where it came from North America? South America? Africa? Well, its been here, there, and everywhere for along time now. It may be an innocent, unassuming looking little plant, but it’s a plant that has to be handled responsibly in your water garden and your local waterways.

Oh water lettuce.

What a Pistia!

34 Comments

dhyumna

Thank you very much. You post about the water lettuce was very helpful. I had bought in a few. While the mother plant were growing daughters, I had some rotting leaves with roots, I wonder if these will also give new plants so I kept them in the little pond I have. I will remove them soon.

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Nico

Tx Mike. Interesting and very accessible information. I just got one unit from a friend who is experimenting with aquaphonics, exchanging it with him for a piece of another water criminal from my own fish pond, the water hyacinth. Out here in Nairobi, Kenya, at 1600m altitude and intense sun, i hope it will form a nice carpet with the hyacinth and lillies which i aim to have cover for max 50%. I intend to set up an external filtration basin to pass the pond water through, maximum covered with hyacinth and lettuce. Until now i have managed to keep the 4000ltr pond pretty clear without a uv-c unit and hopefully the plants mentioned will start rewarding me for my patience. Rgds. Nico

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Mike Gannon

Hey Nico, thanks for reaching out. I’d love to see some photos when the pond is covered! -Mike

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Esther Sunday

thanks for the info Mike. im a postgraduate student and want to experiment water lettuce as a bioremediating plat in the laboratory. and i need ur advice on how to collect the plant from the pond and how it should be cultivated in the laboratory. thankx. Esther

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Jackie

OMGosh great info I bought 3 at a local pond supplier and 2 months later I have at least 500 in my 900 gallon pond!!! I think it killed off my water lilies because they vanished. So far I was able to give 400 away but omgosh they are still reproducing , they look amazing but I cant see my fish or lilies anymore. I have tons of new fish they are mating like crazy in the roots….too many fish now..HA! :/ I thought the turtles would munch on the lettuce but they haven’t touched it. hummmmm

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Mike Gannon

Hi Jackie, those water lettuce get crazy. You may want to purchase a hippo for your pond, they will eat all the lettuce real quick! Good luck! -Mike

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Birgit Hall

Hi, do these just float on top of the water, or should they sit inside a basket-type thingamagig? How long to the roots get, and can these be used in a small, 200 gallon goldfish pond? (6-8in. goldfish) (Sorry, but I’m pond plant ignorant)

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Mike Gannon

Hey Birgit, thanks for reaching out! Yes, water lettuce just floats on the surface of the water. Its roots can be up to 12″ long or more. There are several thing-mo-jigs that can be sued to contain them or just let them free float. Water lettuce will do just fine in a 200 gallon containers w goldfish. Good luck! -Mike

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Mike Gannon

Hi Kathleen, water lettuce will do very well in a smaller container and smaller fish. -Mike

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Ejigah

We have few of them in our earthing pond that is 7mtrs by 14mtrs. Currently, we have them covered all over the surface of the pond. What is the benefit of this plant to catfish? We are yet to see the benefit of this plant to our pond.

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Mike Gannon

Hello Ejigah, I do not know that water lettuce offers any direct benefit to catfish. A side benefit will be a bit of shade for the catfish since they do not like full sun, but otherwise I can’t say there is any other major benefits. -Mike

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Liaqat hayat

Does it help to treat wastewater contaminants in pond as well? Any experience on this?

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Mike Gannon

Hello Liaqat. I have not direct experience, however I do believe it could be helpful improving water quality. -Mike

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Ron

I just put one of these in a small (about 14″ across) pot on my deck. There are no other plants or fish in the pot, just some rocks to stabilize a small pump that keeps the water moving and provides a little interest.
Will the lettuce do well with nothing else growing in the pot? This pot is too small for fish. The raccoons discover them and eat them immediately. Fortunately, they leave plants along.
Should I use any fertilizer in the water?
I’m new to all this. Thanks for the help!

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Mike Gannon

Hello Ron. The water lettuce should be awesome! send pix and good luck! -Mike

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Brad

Good post Mike,I was thinking of feeding these breeders to my chickens since my 450 gallon pond gets overwhelmed & I constantly throw them out but now I will not try that after reading your post. They are amazing plants that help shade & keep my pond clear,the fish luv em too. I tried to winter them in a fish tank but they died rather quickly, any suggestions for indoor survival with limited sun? East coast close to your area.

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Mike Gannon

Hey Brad, thanks for reaching out. For indoor keeping you would want a greenhouse type of scenario unless you have access to some pretty powerful lighting and heating to keep the plants from freezing or prolonged low temperatures. Good luck! Mike

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Mike Gannon

Hello Terri. Water lettuce will die typically with the first frost of the season. Good luck!! -Mike

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Athar

Hello Mike, will water lettuce help in stabilizing the PH level of water.

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Meera

Does water lettuce encourage growth of mosquitoes? And how often it is necessary to change the water?

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Mike Gannon

Hello Meera. I am not aware of water lettuce encouraging mosquito reproduction although in some circumstances I could see how it might. Its typical uses probably would not. I don’t have enough info on how often you should change water, tell me more. Cheers! -Mike

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midwest farmer

Does anyone here know someone in Phoenix, AZ has water lettuce? I would like to have a few for my new pond. Thank you!

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Mike Gannon

Check to see if it is legal in AZ. The use Google to find local vendors. I’m sorry I don’t have any dealers that I am familiar with in your area. -Mike

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Mike Gannon

Hello Lynette. Thanks for reaching out. Yes, it is safe but the koi will probably rip them apart so in that sense I would not recommend it. Enjoy! -Mike

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Katherine

Hi Mike, thanks for the info on this pond plant. I purchased 2 good “mother” plants and now have a lot of daughter’s! I was hoping you would know if its ok to trim the roots of the big ones. They are longer than my ponds are deep. Great for the container ponds as I have lots of baby fish !

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Mike Gannon

Hello Katherine. Glad to hear the plants are doing well!! I see no issue with trimming them up a bit. The roots will grow back quickly I’m sure! Enjoy. -Mike

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Sean Sweeney

Hi Mike, any thoughts on how to take these out of a pond and save them for when it gets warmer or should I just treat these like a normal annual and buy new ones every year? Like a lot of folks on here mine multiplied crazy (first year having a pond). I don’t mind buying 2 next year but if there is a way to keep them over the winter please let me know. THanks!

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Mike Gannon

Hey Sean. For the effort it takes to overwinter those plants I’d suggest just getting new ones next year and treat them as an annual. Good luck! -Mike

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