Needle leaf Ludwigia (Ludwigia arcuate) is a classical aquarium stem plant. This species is loved by freshwater aquarists and enthusiasts because of the highly attractive reddish foliage it possesses. Also, Ludwigia arcuata can be employed as a midground or background plant depending on the tank’s layout.
Nonetheless, growing Ludwigia arcuata is challenging and I disagree with most other articles that say that Ludwigia arcuate is easy to care for and tolerant to different water parameters.
It can be really difficult to turn Ludwigia arcuata red. In addition, it is rather quite sensitive to parameter swings and does not do well in unfavorable tank conditions. Therefore, I would not recommend this plant for beginners.
Keep reading for everything there is to know about Ludwigia arcuata and how you can grow the plant in your freshwater tank.
Quick Notes about Ludwigia Arcuate
| Common Name | Ludwigia arcuata |
| Other Names | Needle leaf Ludwigia, Narrow-leaf Ludwigia |
| Scientific Name |
Ludwigia arcuata |
| Difficulty | Medium-Difficult |
| Lighting | Moderate to high |
| Optimal pH | 5.5 – 7.5 |
| Optimal GH | Soft to moderately hard water |
| Optimal Temperature | 68 – 82 °F (20 – 28 °C) |
| Substrate | Nutrient-rich |
| Can Be Grown Emersed: |
Yes |
| Growth Form | Stem |
| Growth Rate | Slow to moderate (submersed), moderate (emersed) |
| Placement in Tank |
Mid-ground and background |
| Size | up to 50 cm (~20 inches) without trimming |
| Fertilizers |
Needed |
| CO2 | Needed |
| Propagation | Cut off the top shoots |
| Color |
Green to reddish |
Origin of Ludwigia Arcuate
Ludwigia Arcuata, also known as the “Needle leaf Ludwigia” is a species of aquatic stem plant belonging to the family Onagraceae and genus Ludwigia — a genus of about 82 species of aquatic plants native to Central, North, and South America.
The genus was named by renowned Swedish botanist and taxonomist, Carl Linnaeus after Christian Gottlieb Ludwig (1709 – 1773), a German botanist.
Interesting fact: Ludwigia is the only genus that has existed for at least 50 million years based on fossil pollen records.
Habitat of Ludwigia Arcuate
Ludwigia arcuata grows in marshes, ponds, and ditches in the Southeastern United States, prevalent in South Carolina, Florida, and Georgia. Needle leaf Ludwigia can overgrow and grow in swamps and wetlands in optimal conditions.
They grow on land (emersed) and underwater (submerged), making them great aquarium and paludarium plants.
Description of Ludwigia Arcuate
Needle leaf Ludwigia is a beautiful flowering plant. The species is delicate and has green to reddish-looking shoots with narrow, pointed, needle-like leaves that vary from green, orange to red.
The plant doesn’t possess a fast growth habit. It grows rather slowly to moderately and can attain a maximum height of 20 inches (50 cm). Thus, it is well-suited for midground or background placement in planted tanks, but may be used in the foregrounds if trimmed accordingly.
Ludwigia arcuata has varying appearances depending on how it’s grown.
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Emersed form:
Ludwigia growing on land (emersed) have extensive branching and can lie prostrate or flat. The leaves of the emersed plants are typically green. In addition, the leaves have another form under aerial condition, they are round-shaped.
Since Ludwigia arcuata is a flowering plant, it has beautiful small flowers with bright yellow petals which are eye-catching.
The emersed form of Ludwigia growing is pretty resilient and sturdy.
-
Submerged form:
Whereas plants growing underwater have a habit of ascending and growing upwards. The leaves appear needle-like or spear-head shape (up to 1 – 1.5 inches long (2.5 – 4 cm) and 0.16 inches (4 mm) wide) and are green to reddish-orange or reddish-brown. In addition, the foliage is longer and narrower.
The leaves grow along the length of the stem, and they are arranged in opposite pairs. If pruned properly, they can branch out and provide a bushy filler for the aquarium, adding much dimension and movement.
The submerged form of Ludwigia growing is not hardy compared to its emersed form.
Tank Requirements and Water Conditions
Ludwigia arcuata is not one of the go-to plants for beginner aquarists, and this is because it has some specific requirements that can be hard to achieve without proper knowledge.
Nonetheless, if you’re thinking about adding this plant to your paludarium, you will find this plant easy to care for.
Tank size:
Ideally, a 10 gallon (~40 L) tank is adequate for growing a few clumps of Ludwigia arcuata.
Although this is a pretty tall plant, it can be still recommended even for small tanks because of its slow growth rate.
Water type, Temperature, Hardness, and pH:
Temperature: The optimal temperature is between 68 – 82 °F (20 – 28 °C). Ludwigia arcuata does not like cold water and melts easily. At the same time, a very warm temperature makes the leaves smaller.
Interesting fact: Change of culture temperature has the most distinct effect on the shape of submerged leaves in Ludwigia arcuate. Submerged leaves that were formed at 73 °F (23 °C) clearly showed a narrower shape than submerged leaves that were formed at 88 °F (31 °C).
Note: According to the same experiments, light intensity and pH do not have an effect on the shape of submerged leaves
Hardness: Ludwigia arcuata can grow well in both hard and soft water. However, it is best to consider soft to moderately hard water in your aquarium.
pH: Be sure to monitor the pH of the aquarium water. Essentially, a pH level of 5.5 – 7.5 is appropriate for this species. Ludwigia arcuate prefers slightly acidic water.
Lighting:
As you read earlier, good lighting is absolutely necessary for the growth of Ludwigia arcuata. This plant is not a good choice for low-tech tanks.
Therefore, be sure to provide medium to high illumination with higher PAR values since it helps achieve intense red coloration and bushy growth of the shoots.
Also, maintain a standard photoperiod of at least 10 hours daily.
Note: The leaves of this species need adequate light to maintain best coloration. Their leaves grow redder with high light intensity while remaining green in a dimmed environment.
Related article:
Substrate:
Abundant nutrients in the substrate help preserve the color of the stem, the underleaf, and the leaf tips.
Therefore, nutrient-rich substrates (such as ADA Amazonia, etc.) will be the best choice.
Related article:
CO2 and Fertilization:
CO2: CO2 supplementation is highly recommended, it is very difficult to grow this plant without CO2.
Important: You need to understand that high-light demanding plants must be balanced in terms of CO2, and nutrients. Otherwise, you will have algae everywhere.
Fertilization: This species also deepens in coloration with low nitrates (nitrates limitation, at least less than 20 ppm).
Important: If you keep shrimp in the tank with Ludwigia arcuata, I would highly recommend reading my articles:
- CO2 in a Planted Tank Guide
- CO2 in a Shrimp Tank
- How Copper Affects Dwarf Shrimp
- Shrimp Safe Plant Fertilizers
The point is that a high level of CO2 and Copper (most fertilizers contain copper) is extremely dangerous to the shrimp.
Care and Maintenance of Ludwigia Arcuata
Like every other live aquarium plant, it’s crucial to take proper care of Ludwigia arcuata. Here are some necessary things you should know:
- Supplements. This plant needs CO2 supplementation for robust growth.
- Growth rate: This plant grows slow to moderately. You can accelerate the growth in the aquarium by using CO2 and dosing plant fertilizers, which helps it grow fuller and bushy.
- Minerals. Ludwigia arcuata does not require high iron content in the aquarium to produce deeply red stems. It is all about lighting!
- Pruning. Also, the plant tends to overgrow and be bushy. Not only does cutting overgrown stems and branches stop the plant from getting too crowdy, pruning significantly adds to its beauty by keeping the plant compact and well-defined.
- Water changes. Note that drastic changes to the aquarium can harm the plant. Ensure to carry out necessary changes gradually. That way, the plant remains healthy in its new aquatic environment. Water replacement should be carried out regularly. This activity ensures the water is clean and also helps in limiting the nitrates in the aquarium.
One beautiful thing about this plant is its movement with the aquarium’s water current, which is an attractive sight to behold.
Planting and Propagation of Ludwigia Arcuata
Planting Ludwigia arcuata is fairly easy:
- Get ahold of the bunch and separate the stems gently.
- Next, cultivate in groups of two or three stems into a nutrient-rich substrate, and provide bright illumination to promote healthy growth of shoots.
Note: Ludwigia arcuate can also grow aerial roots. So, you can cut this part of the plant above the node and stick it into the substrate.
After a while, you will need to trim the plant to keep it from overgrowing in the tank. Simply snip the top of the plants, i.e. a few inches off the current height, and discard them. Pruning helps promote the formation of side shoots, hence creating a bushy look.
To propagate Ludwigia arcuata, make sizeable cuttings off the stems of several plants and place them into the aquarium substrate.
It’s a great idea to remove the leaves from the last node on the lower end of the stem to encourage root growth.
Alternative Way of Growing Ludwigia Arcuata
Ludwigia arcuate can grow submerged or partially submerged. Therefore, another way to plant and grow this plant is to use the Dry Start Method (or DSM).
The Dry Start Method still significantly boosts the development of the slow-growing plants, cycles the substrate, and removes any algae problems!
It makes this plant a great choice for paludarium setups as well.
Problems Associated With Growing Ludwigia Arcuata
Melting: It may occur in stem plants after physical transfer from an emersed to a submerged environment. Nonetheless, there is no reason to panic.
During this period, it is normal for a plant grown in terrestrial conditions to die back and shed some of its leaves. After a while, Ludwigia arcuate will adapt to the new conditions and then, grow new leaves.
Solution: Wait and the plant will bounce back.
Not Red: Aquarists buy this plant because it looks red in pictures. Unfortunately, in many cases, they can’t get this color and Ludwigia arcuata stays green or only turns slightly orange.
Important: An excess of iron will not make your Ludwigia arcuate red no matter how much you put in.
Solution: There are lots of debates with no confirmed answers. So far, the best recommendation is to get the right conditions: soft water, nutrient-rich substrate, strong light, CO2, and low nitrates.
Extremely slow growth rate: As I stated earlier, Ludwigia arcuata is slow to moderately growing plant species. However, there are occasions where the plant exhibits a much slower growth rate due to factors like inadequate nutrients and insufficient lighting.
Solution: Growing in such conditions may cause Ludwigia arcuata to deviate from its usual growth rate. Luckily, improving on the identified conditions will effectively help restore the plant’s vitality and by extension, its growth rate. This species requires sufficient light to grow maximally.
Discoloration: Whether your Ludwigia arcuata leaves are reddish, greenish, or reddish-brown, there is likelihood of them taking on a faded coloration. Changes in color may be triggered by a deficiency in iron or other essential nutrients that are required for optimal health and development.
Solution: Hence, it is recommended to dose liquid plant fertilizers in the aquarium water regularly to maintain a good supply of nutrients to your live plants.
Pests: Emersed grown Ludwigia arcuata is susceptible to the attachment of organisms such as pond snails, slugs, filamentous alga, and other known hitchhikers.
Solution: Ensure to carry out an initial disinfection or quarantine process before cultivating the plants in your freshwater aquarium. Failure to do so will result in the transfer of problematic critters to your aquarium, and that sure won’t end well.
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Deformity: The lower portions of the stems and several leaves may shrivel slightly.
Solution: Deformity in Ludwigia arcuata is often caused by unstable CO2 levels (or not enough) and inadequate nutrient levels. You need to fix it.
Related article:
- How to Spot Nutrient Deficiencies in Aquatic Plants
- Everything about Nitrates in Planted Tanks
- Phosphates in Freshwater Tanks
Benefits of Ludwigia Arcuata
Aquascape: Ludwigia arcuata can be an excellent decorative addition to Dutch style aquascapes.
No Overshadowing: It will not choke other aquatic plants. Ludwigia arcuata does not grow fast.
Hiding place for fish, fry, and shrimp: Ludwigia arcuata serves as cover and shade for inverts, small frogs, and fish.
Foraging place: Acts as a buffet of biofilm, which is an ideal first food for newly hatched fry and shrimplets.
Oxygenation: Ludwigia arcuata oxygenates and aerates the tank water.
In Conclusion
Ludwigia arcuata is a very attractive stem plant owing to its characteristic reddish foliage. Actually, under optimal conditions, this plant goes an incredible deep wine red color.
The main problem though is that Ludwigia arcuata is not easy to maintain, and it requires CO2, nutrient-rich substrate, moderate to high levels of nutrients, and lighting.
Therefore, this plant is not for beginners and those who seek to carry out little maintenance from time to time, unless you want to keep it in the emersed form in paludarium set ups.