Why is my Lemon bacopa growing green instead of red?

This is usually due to insufficient light. Increase the lighting and add iron into the soil. Softer water encourages the red color to develop. The color returns within a few weeks.

How big does Bacopa caroliniana get in a tank?

If left untrimmed, the stems reach 20-24 inches (50-60 cm) and extend above the water surface. Regular cutting helps keep them shorter and bushier.

Lemon bacopa Care (Bacopa caroliniana)

Also known as: Lemon bacopa, giant red bacopa, blue waterhyssop, mint bacopa, water hyssop

About Lemon bacopa

Lemon Bacopa is a wetland herb. It spends its entire life underwater or on moist soil near the edge of a pond. Aquarists grow it as a submerged stem plant. Outdoors, it grows along the edges of ponds, with its stems above the surface. The leaves are thick, succulent, and almost round. When you crush one, it smells strongly of lemon — this scent gives the plant its name.

In the wild, this is a common marsh plant in the southern United States. Its range extends from the southeastern United States to Cuba. Small blue flowers appear in the warmer months. The plant tolerates various conditions, so it rarely dies. Care for Lemon Bacopa requires maintaining a constant level of humidity, moderate lighting, and some warmth.

Main Plant Requirements

Care Difficulty

Moderate Care

Light Preference

Partial Sun

Water Requirements

Aquatic

Temperature Preference

Tropical / Frost Sensitive

Hardiness Zone

8–11

Soil Texture

Sandy, Loamy, Organic-rich

Soil pH

Acidic (5.5–6.5), Slightly acidic (6.5–7.0)

Soil Drainage

Waterlogged tolerant

Fertilization

Moderate (every 2–4 weeks)

Get Personalized Care Plan

Scan your plant to receive care tips personalized for your specific plant

Available on iOS and Android

How to Care for the Lemon bacopa

Light plays a crucial role in the growth and appearance of this plant.

Bright light for 8-10 hours per day ensures the most vibrant color of leaves.
Bacopa caroliniana also thrives in low light. With less than 6 hours of light per day, the leaves remain plain green.
With PAR levels between 40 and 60, the upper leaves take on a bronze or red tint.

Lemon Bacopa requires simple water conditions, as it grows either in water or in consistently moist soil.

Maintain the pH of the aquarium water between 6.0 and 8.0 for stable growth.
Since this is a marsh plant, keep the water within 2 inches (5 cm) of the crown.
Change 20-30% of the aquarium water weekly to keep it clean.

Warm water promotes plant growth, but the process slows as temperatures get colder.

Maintain a temperature of 68-82°F (20-28°C) in a heated aquarium.
Outdoors, Bacopa caroliniana tolerates summer heat well. At temperatures below 55°F (13°C), its growth slows.
At temperatures below 50°F (10°C), the soft top growth may die.

Humidity only matters when you grow the plant above the waterline, such as in a paludarium or shallow container.

For above-water growth, maintain air humidity at 60-80% relative humidity.
Position the aquarium or container at least 3 feet (90 cm) away from radiators and vents that dry the air.
A transparent lid traps moisture. This helps new above-water shoots adapt.

Most types of substrate are suitable for Bacopa caroliniana.

Use 2-3 inches (5-7.5 cm) of fine gravel or sand to help the roots establish.
Nutrient-rich aquatic soil or clay encourages more intensive growth from the base up.
Avoid sharp and large stones, which can damage the soft stems.

Note: In a well-planted aquarium, Lemon Bacopa thrives alongside Cryptocoryne wendtii and Dwarf Spikerush (Eleocharis parvula).

This plant grows well in containers, aquariums, tubs or water gardens on the patio.

Any aquarium of 5 gallons (19 L) or larger will provide ample space for the stems to grow.
For ponds, place Bacopa caroliniana in a mesh basket with 6-8 inches (15-20 cm) of substrate.
A hanging pot is suitable for above-water growth, as the stems trail and root as they spread.

Feeding helps if you want fast and vibrant growth, the plant develops slowly without it.

Apply a liquid all-purpose fertilizer weekly, immediately after a water change.
Add an iron-rich root tablet to the substrate every 2-3 months.
For thicker stems and brighter color, add 20-30 ppm CO2.
Reduce fertilizing in winter when growth slows.

Note: Pale young leaves usually indicate low iron levels in Lemon Bacopa.

This species grows quickly, so expect frequent pruning once it is established.

Prune the tops to 4-6 inches (10-15 cm) once the stems reach the surface.
Cut just above a leaf node to encourage branching.
Remove yellowed lower leaves that shade the base.
Replant healthy tops to create a bushier plant.

Bacopa caroliniana transplants easily — rooted stems and cuttings establish in a new spot within a few days.

Repot rooted stems in the spring, when warmth accelerates recovery.
Bury 2-3 nodes under the substrate to promote rapid root formation.
Space plants about 2 inches (5 cm) apart to reduce shading.
Gently rinse the roots when transplanting from a pot to open gravel.

For propagation, you can select any pruned tip, which will then grow into a new plant.

Cut a healthy stem 4 to 6 inches (10-15 cm) long just below a node.
Remove the lower leaves in Bacopa caroliniana so that the bare nodes touch the substrate.
Press the cutting about 1 inch (2.5 cm) into the gravel or sand.
Maintain warm water, around 75°F (24°C), for faster rooting.

When growing indoors, winter has little impact on Bacopa carolinica care. Outdoor plants require protection as soon as frosty days approach. In a heated aquarium, growth slows and requires little care.

Before a hard freeze, move the pots with pond water indoors and maintain a temperature of 55-65°F (13-18°C). Water the indoor plant so that the substrate remains soaked, and check this every 3-4 days.

Overwatering

Plant Health Check

Not sure what's wrong with your plant? Check your plant's health inside the app.

Care Tips

Chase the Color

Good light levels and sufficient iron in the soil give the plant a rich and vibrant color. Soft water also contributes to this.

Without all three factors, the leaves turn pale and become simply green.

Float to Root

When propagating Lemon Bacopa, let the fresh cutting float on the surface for a few days.

It will develop white roots in open water, after which you can plant it.

Add CO2

Provide gentle water movement over the leaves to improve CO2 absorption and reduce deformation or stunted new growth.

In order to achieve this, place a CO2 diffuser or outlet near the planting area.

Bag the Air

New shoots that grow above water initially require humid air. Cover them with a transparent bag or lid.

The trapped moisture will prevent the fresh leaves from drying out during the adaptation period.

Common Pests and Diseases

Algae Buildup

Algae can accumulate on stems and old leaves with low CO2 levels.

You'll first see fuzzy green or black spots at the base of Bacopa caroliniana.

Solution

Lower the light to 6 to 8 hours a day.

Raise the water flow too — a few shrimp or snails clean up the rest.

Transient Leaf Dying

Many commercial plants grow above water.

Once submerged, older leaves will rot within a few days, and this is a normal process.

Solution

Trim soft dying leaves and maintain stable water parameters.

New submerged leaves will grow and adapt to the aquarium.

Snail Damage

Snail pests appear on new plants of Bacopa caroliniana and eat soft young leaves.

They reproduce quickly in a warm aquarium.

Solution

Before adding new plants, soak them in a weak salt solution. Remove adult snails by hand.

A few assassin snails will also help.

Interesting Facts

Lemon in a Leaf

If you rub the leaves, you'll smell a strong lemon-mint scent.

Gardeners use this smell to distinguish Lemon bacopa from Water Hyssop (Bacopa monnieri), a very similar plant.

Survives in Brackish Water

This plant tolerates both fresh and slightly salty water.

It grows in the Everglades, where floods and storms annually disrupt the integrity of the shallow waters.

Butterfly Nursery

Bacopa caroliniana is also important for wildlife. It grows in southeastern marshes and coastal shores.

This species also harbors the larval habitat of the white peacock butterfly.

Did you know?

Its blue flowers attract small pollinators in the wild. Escaped populations have even spread to South Korea.

FAQs about Lemon bacopa

Yes. It is non-toxic and provides good hiding places for shrimp and fry. Shrimp eat the biofilm on the stems. Small fish can easily hide among the dense leaves.