A way to naturally get rid of duckweed?? Veronica beccabunga?

[AdoraBelle Dearheart]

I was checking out a pond plant nursery, and the guy talking in the video said they stock this plant called Veronica that is very popular because people discovered it has an enzyme that kills off duckweed, and keeps it in check? Anyone else ever heard of, or tried, this?
I'm very tempted to get some for our pond, which we wind up skimming tons of duckweed from several times a year since it tries to coat the surface. But also wondering whether some of this could be grown emersed from a tank, since one of my tanks has somehow sprouted duckweed again!

 

[AdoraBelle Dearheart]

About Us

Lincolnshire Pond Plants is a business located in the heart of Lincolnshire. We pride ourselves on the quality of our plants and the quality of our service. We stock aquatic plants for ponds as well as tropical fish tanks.

lincspplants.co.uk

This is the video where the guy mentions and shows the plant, and talks about the enzyme/duckweed thing, at about 2:53 in their "about us" video.

 

[GaryE]

THis must be explored!

 

[AdoraBelle Dearheart]

THis must be explored!

Right?? I loathe duckweed, especially in my tanks, so if this would work, I'm so up for trying it! @Byron is pretty knowledgeable about plants, as is @TwoTankAmin

 

[GaryE]

I went digging It appears to use the same nutrients as duckweed, so by competing reduces it. I was thinking of it as an emergent plant, and it would survive roots in - it thrives in up to 4 inches of water as long as the stem and leaves are out. Until then, it sounded great for me, and it still sounds great for you.

Its problem is it needs very bright light, which puts it outdoors and doesn't make me happy. Oh well. I imagine if you got a good border of it going along a pond, it could dent the duckweed and improve the water quality.

It's an invasive plant in parts of North America.

 

[10 Tanks]

Hello. Duckweed is a fact of life. I use a skimming net and remove it when I perform my weekly water change. I don't have any Duckweed in my larger, Goldfish tanks. The fish love it and it's very good for them. So, I just skim it from the tanks that have a lot of it and put it into the Goldfish tanks.

10 Tanks (Now 11)

 

[seangee]

Its problem is it needs very bright light, which puts it outdoors and doesn't make me happy. Oh well. I imagine if you got a good border of it going along a pond, it could dent the duckweed and improve the water quality.

I don't have any Duckweed in my larger, Goldfish tanks.

And there is the crunch. When I was removing bucketloads of the stuff from my tanks every week I simply tipped it into the outdoor pond. My small goldies are around 12" and a couple of the koi are nearly double that. It never managed to last more than a day or two outside.

 

[Alice B]

In a really large Texas pond coated with duckweed, it.took about a dozen Mozambique tilapia to clean it up. Mozambique are the only permitted tilapia species as they die at 55 degrees so don't succeed as an invasive species in Texas lakes and rivers

 

[AdoraBelle Dearheart]

I went digging It appears to use the same nutrients as duckweed, so by competing reduces it. I was thinking of it as an emergent plant, and it would survive roots in - it thrives in up to 4 inches of water as long as the stem and leaves are out. Until then, it sounded great for me, and it still sounds great for you.

Its problem is it needs very bright light, which puts it outdoors and doesn't make me happy. Oh well. I imagine if you got a good border of it going along a pond, it could dent the duckweed and improve the water quality.

It's an invasive plant in parts of North America.

Thank you for going digging! I wonder why that nursery guy said there was an enzyme that it produces that knocks back duckweed? Outcompeting is a different thing, you know. Did you see in the video?

Fortunately for me, the plant is native to the UK, so not an invasive risk. The Royal Horticultural Society does recommend planting it in a pot to contain it though, so sounds like it can spread like mad and be invasive given the chance.
@Wills you also loathe duckweed, live in the UK and grow plants emersed, what do you think?

 

[sharkweek178]

Thank you for going digging! I wonder why that nursery guy said there was an enzyme that it produces that knocks back duckweed? Outcompeting is a different thing, you know. Did you see in the video?

Fortunately for me, the plant is native to the UK, so not an invasive risk. The Royal Horticultural Society does recommend planting it in a pot to contain it though, so sounds like it can spread like mad and be invasive given the chance.
@Wills you also loathe duckweed, live in the UK and grow plants emersed, what do you think?

Maybe he was confusing it with hornwort. I've heard that plant releases an enzyme that inhibits the growth of other plants.
I think you're right here. Some plants are just better at absorbing nutrients than others. And in the limited spaces that are our tanks, it's a zero sum game. There are only so many nutrients to go around. I saw this for myself in my own tank. I planted a bunch of water wisteria and saw visible growth every week. Then I added salvinia minima and the wisteria growth came to a crashing halt. They just weren't able to coexist on that scale in my tank. I took out most of the wisteria except for a few pieces. Those remaining pieces bounced back pretty well.

 

[StevenF]

xThere was a old theory that plants release substances that kill off other plants and or algae. scientist have found no proof of it. However pepole have seen that when they put on plant in an aquarium others die. And others have seen algae grow and the plants die. Looking for an answer they go online and find this theory and claim it explains what's happening in there tank.

What people are seeing can all be explained by nutrient deficiencies. Algae does best in low neutrient levels but at those levels most plants die. In other cases adding a fast growing plant can reduce the nutrient levels in the tank. The new plant can handle that but otheres cannot. So some plants die off. The nutrient deficencies explanation works a lot better than some chemical scientist have not been able to find for 80 years.

But looking at the video the plant they pointed to is rooted in the substrate and produces a dense canopy several inches above ether water. The canopy would block all or most of the light at the waters surface which will kill duckweed.

I have observed red root floaters also creat a dense canopy the can be at least 1 inch thick above the water surface. When I saw this after a vacation, it had killed most of the Salvinia in my tank. If I had any duckweed in the tank it would have been smothered and died. I cleared much of the duckweed in my tank years ago by daily removing all the duckweed I could see. It took several months to elliminate it.

 

[Wills]

Thank you for going digging! I wonder why that nursery guy said there was an enzyme that it produces that knocks back duckweed? Outcompeting is a different thing, you know. Did you see in the video?

Fortunately for me, the plant is native to the UK, so not an invasive risk. The Royal Horticultural Society does recommend planting it in a pot to contain it though, so sounds like it can spread like mad and be invasive given the chance.
@Wills you also loathe duckweed, live in the UK and grow plants emersed, what do you think?

Seems to be a bit of logic in the above posts but if you wanted to grow it you’d need to do it in a substrate tray hanging from the top of the tank - some clay like substrate in a pond basket for example. It will look nice and if it’s known to grow fast and take nutrients win win really

 

[seangee]

If I had any duckweed in the tank it would have been smothered and died. I cleared much of the duckweed in my tank years ago by daily removing all the duckweed I could see. It took several months to elliminate it.

The war on duckweed can be won, but that is pretty much the only way. If you only fight it on weekends you will never win. And don't forget your pump, filters, nets, caves etc etc. It only takes one piece of an apparently dead leaf...
I'm not saying you are wrong about the floaters but I had a really thick canopy of frogbit with duckweed clinging to the roots and leaves. In the end I cleared out the frogbit and went to war against anything that floated. Unfortunately it took me months to realise that attacking it weekly was not enough,

 

[GaryE]

As I've moved a few times, each different water table supports different plants. I had one house where hornwort ruled, and another where it could barely grow. In my latest move, hornwort lingers, so I just got Najas to try.
Ludwigia goes crazy in the new to me water here.
I use some root tabs, but floaters are on their own.
It only makes sense that different plants have slightly different diets than others. The idea with Veronica spp as pond plants is they feed the same as duckweed, so they can reduce the population if their competitor. I didn't watch the video but went to print sources online and had a look at the question raised. It isn't a natural bullet, but maybe a natural enemy of duckweed,
I grow a lot of marginal plants in open topped tanks with raised areas, so the roots are in water of in substrate, but the leaves and main stems are dry. I'm always on the lookout for bog plants, but alas, this one won't do.

I managed a pond at a workplace, and one year the duckweed was bad. With no plan in mind, I found some liner and the next Spring dug a stream about two feet wide and 18 feet long, curving behind the main water. I moved a pump and had a nice little babbling brook. I was experimenting with marginal plants just for fun, and some swamp mint I put in on the edges took over, colonizing the shallows. In the second year, the duckweed was reduced by 90%, and it never became an issue again even though it was always present. The current in the main, deeper pond was next to nothing. The swamp mint in my stream was choking sections and I was pulling it out by the bucket full. I kept no notes, but assumed there was a nutrient war and the duckweed was losing. Since the water looped through the stream, I had an 18 foot nutrient filter.

A similar set up with a plant that used the same nutrient profile as duckweed would make a pond pretty inhospitable for the pest plant.

 

[seangee]

I'd go one step further. Each tank (or body of water) develops its own unique biology. I have thriving frogbit in 3 of my tanks and cannot keep it alive in the fourth (that one has salvinia). In 2 of my tanks I have spidergrass doing really well and I cannot get it to take in the other 2. Since my hobby is keeping fish,and the plants are only there for their benefit I don't stress about this or try to analyse why. If it works it stays, otherwise it doesn't.

I do know that the pH is quite different in each of these tanks. For 3 of them there is no obvious explanation (I do raise the KH in the shrimp tank) and I am not going to try to find out why this is the case.