Pearl Weed (Hemianthus Micranthemoides): Care Guide

Common Name(s)Pearl Weed
Scientific NameHemianthus Micranthemoides
OriginNorth America
Ease of GrowingEasy
Height2-5 inches
Temperature66-82 °F (19-28 °C)
Growth RateModerate to Fast
PropagationStem cuttings from a mature plant
Light RequirementMedium light (25-50 lumens per liter)
CO2 RequirementCO2 is not required, but it may help increase the growth rate.
Pearl Weed
Pearl Weed (Hemianthus Micranthemoides)

As an aquarium hobbyist, you are likely always on the hunt for beautiful and easy-to-care-for aquatic plants to add to your collection. Look no further than hemianthus micranthemoides, commonly known as pearl weed, pearl grass, or baby tears.

Pearl weed is a plant that is native to Florida and can be found in its natural habitat of wet areas with stagnant waters. In an aquarium, it is a versatile plant that can be used in the midground or background, as well as a carpeting ground cover or attached to driftwood. Pearl weed is also easy to care for and very hardy, growing quickly with proper care. There’s a good reason it’s one of the most popular aquatic plants!

If you have recently bought a pearl weed, or are thinking of it, read on to learn more about pearl weed care. This guide covers all the most important information on caring for your plant and making the most of it in your aquarium.

What is Pearl Weed?

Pearl weed (Hemianthus Micranthemoides) is a popular aquatic plant known for its bright green color and low-growing, full-coverage growth. It is easy to care for and can be grown in many sections of the aquarium. Pearl weed is native to Florida and will grow in wet areas with stagnant water.

Other features of pearl weed are that it can grow very dense and cover the bottom of the tank as a carpet or attach to driftwood. Pearl weed is one of the most popular aquatic plants because it is easy to care for and doesn’t require much special care. However, knowing how to care for a pearl weed will encourage growth and keep it healthy. We will look at pearl weed care in the next section.

Pearl Weed Care

Lighting Requirement

Pearl weed requires medium-level aquarium light to grow, but high levels of light will encourage more compact growth. If you want that busy, full-coverage growth from pearl weed, perhaps to carpet the floor of the tank, consider buying a high-intensity light. This means looking for a light that has at least 25-50 lumens per liter, which is considered medium, or 50 and over for the best results.


Pearl weed is a hardy plant that can live and grow in water temperatures of 66-82 °F (19-28 °C). This is considered cool to average temperature. Most tropical fish will be healthy in a range of 75-80°F (24-27°C), so the pearl weed will easily grow in that temperature.

Water pH

Pearl weed will grow best in water pH conditions that are slightly acidic to neutral, or approximately 6.5-7.5 pH. However, pearl weed is a very adaptable plant and can survive in various conditions.

The pH of an aquarium will change depending on the type of fish living there. Some saltwater fish require basic pH levels, while tropical fish require more acidic or neutral pH levels. Since the pearl weed thrives in acidic to neutral conditions, it is best suited for aquariums with tropical fish.

Pearl Weed Growth Rate

Pearl weed has a moderate to fast growth rate.

Pearl weed will initially grow slowly until it takes hold in the substrate. Once pearl weed takes hold in the substrate, it can grow rapidly, covering the bottom of a small tank in about three months.

Pearl weed has a fast growth rate and will require weekly trimming. Regular pruning will allow pearl week to grow quickly, stay healthy, and maintain a full and busy appearance.

How many inches per month does pearl weed grow?

The growth rate for a pearl weed depends on a few factors, including light, pH, CO2, and other factors in the aquarium. However, it is possible to make some generalizations. Pearl weed can grow quickly and cover the bottom of a small tank in 2-3 months, giving it a growth rate of approximately 5-8 inches per month.

Pearl Weed Growth Height

Pearl weed is an aquatic plant that primarily grows horizontally to carpet the tank bottom. Thus, it does not grow very tall. The growth height of a pearl weed is about 2-5 inches tall. It may grow taller if it is not regularly pruned, but pruning is recommended to encourage growth to achieve the full and busy look that is so attractive in an aquatic tank.

Pearl Weed Co2 Requirement

Pearl weed is a very easy-to-care-for plant and can be very low maintenance. However, if you are looking for optimal growth and appearance, a CO2 injection can be helpful. Aquarium CO2 injection for a pearl weed is unnecessary, but it can promote full, dense growth and encourage a faster growth rate.

If you want your pearl weed to look its best, consider a CO2 injection to promote full and dense growth so that it can cover the bottom of your tank. A CO2 injection into the aquarium will also facilitate pearling of the pearl weed, giving the plant its unique shape and look.

Pearl Weed Propagation

Pearl weed will grow, like most aquatic stem plants, but placing the stems into a substrate. To propagate pearl weed, gently cut a piece of a mature and healthy plant, bundle a few stems together, and place them in the substrate. If your aquarium has good conditions for growing pearl weed, the stems will root into the substrate and continue to grow.

Pearl Weed Aquarium

How to Grow Pearl Weed in an Aquarium

Pearl weed can grow in an aquarium by either being placed into a substrate or being allowed to float in a tank. If the pearl weed is planted into a substrate, it will grow to carpet the bottom of the tank or can grow on driftwood. It has a dense, bushy look to it that is attractive and can be used in any area of the tank.

Is Pearl Weed easy to grow?

Pearl weed is easy to grow and can survive and grow under most conditions. It does not necessarily need a high-tech aquarium. However, optimizing conditions like pH and light, and providing a CO2 injection will allow pearl weed to grow optimally and become healthy and attractive in your aquarium.

How to Plant Pearl Weed in an Aquascape

How to grow a Pearl Weed Carpet

A pearl weed carpet to cover the bottom of the tank can be grown by carefully and regularly pruning the pearl weed plant. You can also propagate the plant by cutting pieces of a mature pearl weed and placing the stems in the substrate to root. This will allow the pearl weed carpet to grow more quickly.

Can you grow Pearl Weed floating?

Pearl weed is a versatile plant that can grow floating if you want. It can also grow tied to driftwood or as a carpeting plant.

Can you grow Pearl Weed emersed?

Pearl weed is a plant that can grow in a number of different ways, including emersed. Emersed plants are those that rise out of the water. Pearl weed’s natural habitat in Florida is in stagnant, still waters, where it can grow emersed.

Be aware that one problem with pearl weed is that it can “melt” when moved from an emersed to a submersed environment. This move can trigger the plant to respond negatively to the new environment and shed a number of leaves. However, once it gets used to the new environment, it can continue to grow.

Can Pearl weed grow without soil/substrate?

Because of the versatility of a pearl weed plant, it can grow and thrive under a number of different conditions. A pearl weed plant can grow without a substrate if the water column contains the appropriate nutrients. Pearl weed can grow as a foreground or background plant, carpeting the floor, or can grow emersed or as a floating plant.

Where to Find Pearl Weed for Sale

Pearl weed is a fairly common aquatic plant. It is popular because it is easy to care for and can grow under various conditions. Because of its popularity, it is possible to purchase pearl weed anywhere you would buy aquarium supplies, including online and in-store retailers.

Pearl Weed Cost

Pearl weed is a popular plant and easy to find wherever you purchase aquarium supplies and aquatic plants. The cost of pearl weed is approximately $10-20 per plant, depending on the size and where you purchase it.

Because pearl weed is an easy plant to propagate, it is possible to continue to grow your pearl weed after purchasing it and create more plants through the propagation process. This is a way to save money on your pearl weed.

Pearl Weed (Hemianthus Micranthemoides) vs. Monte Carlo Plant (Micranthemum tweediei)

When people are looking for carpeting plants for their aquarium, they may consider a few different options. Pearl weed (hemianthus micranthemoides) and monte carlo (micranthemum tweedei) are both popular carpeting aquatic plants with similarities and differences.

The similarities between pearl weed and monte carlo are that they are carpeting plants that will cover the floor of a tank and can also grow under normal conditions. There is no need for a high-tech tank for either of these, as they are hardy and can grow well under any condition. Of course, creating optimal conditions and using CO2 injections will help the pearl weed and monte carlo grow and thrive.

The difference between the pearl weed and monte carlo plans is that monte carlo has a stronger root system and will, therefore not as easily get uprooted.

Pearl Weed (Hemianthus Micranthemoides) vs Dwarf Baby Tears (Hemianthus callitrichoides)

Pearl weed (hemianthus micranthemoides) and dwarf baby (hemainthus callitrichoides) are carpeting aquatic plants that provide attractive coverage to any tank. They are similar in that they carpet, but also have some differences.

Dwarf baby tears and pearl weed plants are different in a few ways, including the fact that dwarf baby tears have much smaller leaves. Dwarf baby tears have small leaves and are good for small tank sizes. Dwarf baby tears also grow well with high levels of CO2 and require CO2 injection in the aquarium. On the other hand, Pearl weed does not require CO2 to grow, although an injection will help it grow full and bushy.

Both are good options for a carpeting plant, but pearl weed is better if you are looking for something very easy to grow, as it is less particular about the CO2 conditions of the dwarf baby tears plant. However, if you have a small tank, you might consider the dwarf baby tears plant as it is a little smaller.


After reading through this guide, it might seem that there is a lot to know about taking care of your pearl weed plant! And while that is true, the pearl weed is an easy-to-care-for plant that is appropriate for beginners and those with low-tech tanks.

Pearl weed plants do not need much special care and will grow under most conditions. However, if you want optimal growth, optimizing your tank’s lighting, pH, and CO2 conditions is important. Pearl weed plants do well with medium to high light and slightly acidic to neutral pH levels. They also grow better with CO2 injections, which will help the plant grow bushy and dense.

Pearl weed is versatile and can grow as a carpet, floating, emersed, or attached to driftwood. This means it can be planted just about anywhere in your tank. It is also fairly easy to propagate the plant. Remember to handle it carefully, especially while waiting for it to root in the substrate.

Pearl weed is a very attractive and easy-to-care-for plant. This guide has covered all the important details about pearl weed care. It’s an excellent choice for either a beginner or an expert. We hope that you enjoy your new aquatic plant! 

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