How to Plant & Grow Mosaic Plant (Ludwigia sedioides)

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mosaic plant ludwigia sedioides in a pond
Photo by David J. Stang / CC BY-SA

Belonging to the evening primrose family, Onagraceae, and the water primrose genus, Ludwigia, mosaic plant, also called mosaic flower or false loosestrife, is one of the very few members of this genus that belongs south of the equator. Of Onagraceae’s 655 species and Ludwigia’s 75 species, the vast majority are found in temperate North America. Mosaic plant is an outlier of both its family and genus – it is native to South America, primarily Venezuela, Panama, Columbia, and Brazil. As such, it thrives in warm, sunny, damp conditions.

Its unique appearance is what has led to its worldwide popularity as a garden pond and bog plant. The leaves of mosaic plant whorl outward in a circular basal rosette that floats atop the water’s surface, with each diamond-shaped leaf resembling a tiny, intricate tile within a mosaic pattern. To further this likeness, when in full sun the leaves will go from being entirely green to having deeply red-tinted edges, as though painted. Some of the leaves toward the outside of the rosette may turn entirely red.

Facts, Benefits & Uses of Mosaic Plant

how to plant mosaic plant ludwigia sedioides in ponds
The yellow flowers of mosaic plant draw in different pollinators. A A Prasannakumari / CC BY-SA

The yellow, buttercup-like flowers that bloom throughout summer draw in beneficial pollinators like various bees and butterflies. Since mosaic plant floats atop the water’s surface and extends its roots to the bottom of the waterbody, it’s able to absorb excess nutrients and pollutants throughout the water column.

The floating rosettes also help to shade the water, reduce algae, and provide cover for any pond residents from predators. Absolutely do not plant this in natural waterways, only your own garden pond, as it can become invasive and the damages will far exceed any potential ecosystem benefits.

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Mosaic Plant Fact Sheet:
Herbaceous Aquatic Perennial (Annual in northern regions)
USDA 8 – 11
Full sun to partial shade
June – August (Summer)
Spread 30 – 60 cm (12 – 24in)
10 – 46 cm (4 – 18 in) of water
pH 5.5 – 7.5

Mosaic Plant Growth, Hardiness & Climate

mosaic plant ludwigia sedioides hardiness
Ludwigia sedioides does best in warm, acidic waters with full sunlight. Scott Zona from Miami, Florida, USA / CC BY

Mosaic plant is fairly slow-growing, usually taking an entire season to reach its maximum spread of up to two feet. As a native of South America, L. sedioides is not tolerant of cold temperatures – in fact, if the water temperature drops much below approximately 70° F (21° C), mosaic plant will struggle to grow. Below 65° F (18.3° C), and most mosaic plants begin to die. Keeping the water between 70 and 80° F (21-26.6° C) is best for sustained growth, healthy leaves, and colourful blooms.

As a tropical plant found primarily in bogs, mosaic plant does best in full sun, though it can tolerate some shade. Alkaline water is not conducive to this plant, so be sure to not allow pH to exceed 8, though 5.5 to 7.5 seems to be the sweet spot for this unique plant. Yellow flowers approximately two inches in diameter will bloom from June through August, attracting bees and other helpful pollinators.

How to Plant Mosaic Plant In Ponds

planting mosaic plant in ponds
Mosaic plant can be planted by simply placing it atop the water, or rooted in substrate or thick soil like clay. Heribert Pohl from Germering bei München, Bayern / CC BY-SA

In its natural range, studies have found that mosaic plant is most often found in still waters averaging three feet or less in depth that are protected from wind and waves. A generally easy plant to grow if pH and temperature are right, there are a couple of ways that you can plant it. You can simply place it to float atop the water, where its stem and roots will grow downward over time. Depths ranging from four inches to two feet are acceptable.

Alternatively, you can place L. sedioides in aquatic substrate, clay, or silty-loam up to its crown (where the roots and stem of the plant meet) in an aquatic planting basket or submerged pot. The latter is a good option if you live in a subtropical area where mosaic plant won’t die off from winter and as such can overtake ponds, as the basket or pot will help somewhat to control spread. Mosaic plant prefers nutrient-rich silty or clay soils, but will often do just fine in aquatic substrate.

How to Care For Mosaic Plant

mosaic plant care in pond ludwigia sedioides
In warm regions where winter doesn’t control its growth, mosaic plant can form dense mats if not cut back. Yercaud-elango / CC BY-SA

The main things that you’ll need to do for mosaic plant are regulate water temperature and pH to match the specifications discussed above. In addition, trim off any dead or dying foliage, including flowers, to encourage healthy growth. As always, remove any detritus from the water to facilitate healthy water quality. When first planting, you can place a fertilizer tablet in the basket or soil just below the plant’s roots (not applicable if you allow the plant to float, of course).

If you live in an area that doesn’t experience particularly cold winter temperatures, you’ll likely need to keep mosaic plant cut back so that it doesn’t overtake the rest of your pond. Be sure to properly dispose of any cuttings in the trash or compost; don’t just toss them aside, as mosaic plant primarily spreads via cuttings and these could either re-establish in your pond or, much worse, in a natural waterway.

If you live in a cooler region, such as the Midwest of the US, there should be no need to trim mosaic plant back as the harsh winters will kill them off each year.

How to Winter Mosaic Plant

In subtropical or warm areas like South America, portions of Asia, the American southwest, and so on, mosaic plant should be able to survive winters so long as water temperatures are kept at or above 70° F. In temperate regions, mosaic plant can either be allowed to die out for the winter or you can transfer it indoors to an aquarium. The easiest method is generally to just buy a new one each spring, but it is possible to overwinter them indoors.

Is Mosaic Plant Toxic, Poisonous or Invasive?

Just as with any other plant, mosaic plant is invasive outside of its native range. Ludwigia species in particular are known to become invasive, as they are able to easily spread by division, either when their stems naturally break off or they are manually cut by people. Sri Lanka in particular is having significant issues with controlling invasive mosaic plant that has formed thick mats, choking out native vegetation and blocking waterways.

All invasive instances of mosaic plant are due to escaping from cultivation from water gardens or being erroneously disposed of or planted in natural areas. Even incredibly small fragments, as short as 1 centimeter, can form new plants.

Mosaic plant is not known to be toxic.

Is Mosaic Plant Edible? Will Fish Eat it?

Mosaic plant isn’t particularly palatable, but it is technically edible. Many koi are known to be somewhat adventurous eaters, often sampling pond plants. Curious koi and goldfish may try to eat mosaic plant, and while it won’t hurt your fish, mosaic plant has brittle stems that can break if tousled too much. As such, mosaic plant is recommended for ponds without fish.

Where to Buy Mosaic Plant & Seeds? (UK & US)

If you live in a warm region that doesn’t experience cold or snowy winters, it’s likely that you’ll be able to find mosaic plant at an aquatic nursery or aquarium retailer. Otherwise, nurseries may be able to order it in. The easiest way to acquire it is via online outlets.

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2 thoughts on “How to Plant & Grow Mosaic Plant (Ludwigia sedioides)”

  1. What does the seed look like? I purchased seed from a chinese source that was round and 2.5 mm in diameter. It did not produce L sedioides.
    Can L. Sedioides be grown in alkaline water that has had its ph reduced by adding acid?

    • Hi Phillip,

      Thanks for reading!

      I had a similar experience with purchasing flower seeds earlier this spring – I got roped into a cheaper price and wound up with not only the wrong seeds, but seeds that did not germinate!

      I’m honestly not entirely sure what L. sedioides seeds look like, as I’ve only experienced growing it from cuttings and have not personally seen them go to seed. I know there are a lot of markets that misidentify plants or purposely sell the wrong thing to buyers, particularly those offering plants for quite cheap, so it sounds like that’s what happened to you. Your best bet with mosaic plant is to just grow it from cuttings. These can be easily found for purchase online, and you’ll be able to more easily verify that you are being sold the right plant.

      Mosaic plant is not tolerant of alkaline water with a pH above 8 (and does best in pH’s below 7.5), so if you were able to reduce your pH below this, it should be just fine. There’s a fair amount involved in safely reducing pH, though – if you just add in an acid, it’s likely that your pond’s natural alkaline buffers will raise the pH back up again before too long. We actually have an article that breaks down how to lower pond pH, if you’re interested:


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