What's happening to my water lettuce?

[maybedave]

I was told by the shopkeeper, where we bought these, that the fish in our pond were eating the roots. Some Googling validated that, so we netted off a section of the pond, and yet they seem like they've gotten worse. Water Ph is a tad high, but ammonia, nitrite, and phosphate levels are all good. Any advice would be greatly appreciated!

 

[Lisak1]

You will find that different people have different results with floating plants, including water lettuce. I have never been able to grow water hyacinth in my pond, but they grow great in my pondless waterfall and my patio pond. I always assumed it was my fish, too, but this year I tossed one in the pond (once they start to take over everywhere else I'm always looking for new homes!) and it looks great. It will probably take over the whole pond before the season is over. I have no explanation for it.

You might try putting them in a bucket of pond water with some Miracle Gro for a few days. That frequently helps when they are struggling. Just be sure to rinse them off before you put them back in the pond. Although to be honest, they do look awfully far gone.

 

[poconojoe]

Maybe, to help diagnose, post up your zone or location, the recent weather conditions and how much sun exposure your pond is subjected to.

I have partial sun. I'm in zone 6b, northeastern Pennsylvania. The past few years have not been very good for water lettuce or water hyacinths.

For some reason they are doing very good this year. I can't explain it. The only difference to my pond is that I got rid of my filters and now filter with a bog. I don't see how that would matter though.
I'm guessing it depends on the particular variety of plants. Maybe all water lettuce and hyacinths are not the same.

 

[Lisak1]

Maybe all water lettuce and hyacinths are not the same.

That's a good point! I've noticed the last two years that my hyacinths are HUGE! I've never had them grow this big before- the leaves are GIANT! I wonder if we do get different things that are all sold under the generic name lettuce or hyacinth?

 

[poconojoe]

That's a good point! I've noticed the last two years that my hyacinths are HUGE! I've never had them grow this big before- the leaves are GIANT! I wonder if we do get different things that are all sold under the generic name lettuce or hyacinth?

I'm guessing different strains.
Mine haven't done this great in a long time.
I remember a couple years where the pond was completely covered. I was netting them out like crazy. I had a huge mulch pile of them. Then, for several years, they were duds.

 

[Stephen Noble]

I agree with the above comments. Really, they look to me like they are starving, battered and perhaps sunburned. Are these a new introduction to your pond? How large is your pond and how many fish & type do you have? Water lettuce is hard to kill. How long have the plants been in your pond? Take Lisa's advice, move some into a container and feed them.

 

[GBBUDD]

heat

 

[maybedave]

Thanks, everyone. I'm in Southern CA, so the pond gets plenty (too much) sun. So water lettuce doesn't do well in full sun, huh? We are considering shade sails to help control the algae.

Stephen, these are indeed new to the pond, about 2 months ago. It's 750 gallons with 5 fish. 4 baby koi and 1 bigger grey fish that I have no idea what species. I'll give the Miracle Grow a shot. Thank you!

 

[Mmathis]

I have never had luck with water lettuce, but water hyacinth does OK. Well, to be truthful, I really only tried WL one season, and it didn’t appeal to me — not really that it did poorly.

 

[Lisak1]

It's 750 gallons with 5 fish. 4 baby koi and 1 bigger grey fish

Give us a shout when you're ready to discuss why a 750 gallon pond is too small for four koi... who won't be "babies" for long!

Also - shade has very little to do with algae control. Your algae might be greener in the sun, but it's not growing BECAUSE of the sun. Algae grows because there are excess nutrients in the pond to feed it... commonly caused by too few plants, too much organic material decaying in the pond, overfeeding... OR too many fish! (It's like a THEME!)

 

[ReneeFLL]

Give us a shout when you're ready to discuss why a 750 gallon pond is too small for four koi... who won't be "babies" for long!

Also - shade has very little to do with algae control. Your algae might be greener in the sun, but it's not growing BECAUSE of the sun. Algae grows because there are excess nutrients in the pond to feed it... commonly caused by too few plants, too much organic material decaying in the pond, overfeeding... OR too many fish! (It's like a THEME!)

Who said anything about his pond being to small for his fish?

 

[maybedave]

Algae grows because there are excess nutrients in the pond to feed it... commonly caused by too few plants, too much organic material decaying in the pond, overfeeding... OR too many fish! (It's like a THEME!)

Hence the attempt at water lettuce. Algae blooms have definitely been less since the lilies are doing well.

I was told that the fish would only grow to the size allowed by its environment, but perhaps this is wrong and a tough lesson I’ll learn soon? Definitely making up as I go, so I appreciate the education.

 

[Michael from Daytona]

I was told by the shopkeeper, where we bought these, that the fish in our pond were eating the roots. Some Googling validated that, so we netted off a section of the pond, and yet they seem like they've gotten worse. Water Ph is a tad high, but ammonia, nitrite, and phosphate levels are all good. Any advice would be greatly appreciated!

Hi, MaybeDave, koi will eat water plant roots if there's not enough organic material suspended in them. The roots are quite filamentous and are great natural filters for everything from algae to dead bugs and in between. Normally koi just "forage" in the roots, sucking out good stuff, but if there's not enough in there, or if they're not getting enough koi food, they will eat the roots themselves and the plant will start to die.

While water lettuce does not flower and is not a particularly attractive plant, it is so useful to ponds in so many ways that the pluses far outweigh the minuses. As I said, it's a great natural filter but it also proliferates rapidly through rhizome-like projections that extend in all directions, each rhizome producing a new plant bud. The plants will stay held together tightly by these umbilical cords and if left alone will eventually cover the entire pond surface. Once a bud's own roots are long enough to serve as ballast, if the rhizome is broken, the new plant will stay floating upright, surviving and flourishing on its own. Here in Florida, summer days provide enough heat to raise pond temperatures above 90F. I hear poached koi does not taste good. By allowing the WL to cover large areas of the pond, the shade provided by the heavy leaves can make a difference of five to ten degrees in surface water temperature. In addition, this plant cover gives fish a way to hide from predators and relax in privacy (they can not only see people next to the pond - they can recognize them!).

Your WL looks quite a bit different than that commonly found in Florida. The leaves appear to be thicker and smaller. Don't worry about the dead outer leaves. They are a result of earlier root damage. If you want to replenish your supply, I recommend you pull out 10-15 of the healthiest looking plants (judging by root condition). You can pull off the outside layer of the brownest looking leaves as long as the plant does not flop over when you put it in a water tank. The idea of "netting" your floating plants to protect them is a logical one, but sometimes there are other, in-pond causes of plant disease such as pH extremes, organic toxins or pathogens that can confuse the situation.

I use ordinary tap water and a plastic planter holder (about 3 gallon capacity). Don't worry about nutrients yet. Put your selected plants in with enough room that you can see how fast the roots are recovering in a week or two. Place the planter in partial sun. After two weeks, you should notice new growth or the appearance of rhizomes. At that point you can put in a pinch of Miracle-Gro blue crystals. If the water is beginning to show algae or dirt don't worry about it. Pictured below is a planter of WL I grew from ten plants I rescued from the koi 3 weeks ago. There are a couple brown spots from the original damage but on the whole, the plants are ready to go back in the pond.

The other photo shows one of my two connected (by stream/waterfall) ponds, each a freeform concrete shape two feet deep and about the same volume as your pond, with the top twelve inches of coaming coated with oyster shells in mortar. I also have alisma plantago (bottom right) and water lilies growing from pots about a foot below the surface. The plants on either side of the waterfall are four o-clocks growing wild.

Good luck with your pond!

 

[GBBUDD]

Water lettuce from my experience suffers greatly in high heat

 

[brokensword]

Water lettuce from my experience suffers greatly in high heat

I read re heat/sun too and always thought it was detrimental but I've been growing my WL for a few years now in both full sun and part with no ill effects. The largest issue I have is in the spring when putting them out from under lights to early season sun; they do tend to get burned and until they rebound (which they usually do), they look a lot like the OP's pic. If the temp gets too low (or I put them out too early), again, the plants suffer. Hence why I keep some back in the basement, just in case I lose it all or the fish are extra hungry in the spring. But really, we get some high heat days/weeks and I've never seen any harm done to WL.