An often-overlooked aquarium plant, Hygrophila corymbosa (also known as giant hygro) is not only beautiful but easy to care for and affordable as well! This species grows quickly, forming attractive clumps that look like little green boats floating on the surface of the water.
When it comes to aquarium plants, the true water hygrophila, Hygrophila corymbosa, also called giant hygro, may just be one of the most popular species in the hobby. Easy to care for and hardy, this aquatic plant can be used both in freshwater and marine aquariums with ease, making it an ideal choice for aquarists of all levels.
Hygrophila corymbosa gets its name from the Greek root hygro, meaning moisture, and phyllos, meaning leaf. Although it is now commonly sold as an aquarium plant, the giant hygro was originally native to Southeast Asia and Malaysia. This plant can grow up to 3 feet tall, although they are typically smaller in home aquariums and will get no taller than 1 foot.
In this guide, we’ll take a look at everything from how to grow and care for this plant to its personality traits in your tank environment so you can determine if it’s right for you!
Origin and descriptions
Native to South Asia, Hygrophila corymbosa is a popular aquatic plant in freshwater aquaria. The scientific name for giant hygro is Hygrophila corymbosa, which means water-loving with cymes. This refers to how, when happy, it tends to grow at all angles in terms of stems and leaves as well as into any available space within its aquarium environment. It grows quickly under proper conditions, turning full sun to high light areas into virtual greenhouses.
However, although Hygrophila corymbosa can adapt fairly easily to fluctuating lighting conditions such as those produced by natural sunlight passing through clouds or on rainy days, making sure that you provide stable lighting is important because doing so will allow your plants time enough to adjust their growth patterns while they’re still young and flexible enough to do so without suffering major setbacks or even death if there’s an abrupt change in light quality or duration.
The Giant Hygro is an extremely adaptable plant from the Acanthaceae plant family. As a new aquarium hobbyist, it’s important to understand how fast-growing aquarium plants such as these can be. It typically grows 0.1-0.2 inches per day when under ideal conditions, so expect your giant hygro to grow about 1 foot every 2 months if you keep it well fed with CO2 in high light levels!
Grows horizontally rather than vertically – however, it will take on a mounded shape as opposed to just being a single plane at some point depending on aquarium height, Use Co2 injection – responsible for creating larger stalks and enhanced growth rates; easily purchased online or at any pet store Lighting – 5 watts per gallon over CO2 recommended for optimal growth.
As long as you meet their basic requirements of moderate lighting and fertilization, they are very forgiving of other environmental fluctuations. Be sure to follow our care tips below for the best results!
Hygrophila corymbosa height
This variety of the hygrophila stays at around 10-15 inches (25-38 cm) in height.
It is generally recommended that Hygrophila corymbosa should not be kept in tanks smaller than 10 gallons; however, some have been grown quite successfully even in Nano tanks of around 3 gallons.
Hygrophila corymbosa propagation
Hygrophila corymbosa propagates easily from both seed and stem cuttings. Seeds are often produced by aquarium specimens in response to a change in light levels or water flow. A mature plant will occasionally produce seeds, but more frequently, they can be obtained by carefully plucking them off of an established specimen. Seeds can be germinated in damp sand placed into a sealed bag with no additional light source.
Germination usually occurs within 3–4 weeks at room temperature (~20°C). The resulting young plants may then be transplanted into small pots containing aquarium substrates, such as laterite or LFS medium. Stem cuttings may also be used for propagation if grown under high humidity and warmer temperatures than typical lighting conditions (27-30°C).
Plants typically do not root well directly under lights due to excessive transpiration; therefore the use of a humidity dome is recommended when taking stem cuttings. Plantlets develop roots after approximately 1 week, so must be removed once roots have formed to prevent overpotting.
To prevent spindly growth, it’s best to wait until sufficient roots have developed before transplanting into larger containers or tanks.
Hygrophila corymbosa care
Take great care in your selection of aquarium for your giant hygro. The leaf will grow to about 6 inches and, as a result, require a large tank with adequate lighting and CO2. Be sure to provide gentle filtration. Hygrophila corymbosa can tolerate a range of water parameters but do best with moderate hardness and acidic pH. For optimal growth, keep the temperature between 72–78 degrees Fahrenheit (22–26 degrees Celsius).
In general, Hygrophila corymbosa thrives in low to medium light. However, it can also adapt to higher lighting conditions. Keep in mind that its leaves will grow more compact with higher lighting. If you’re growing in low-medium lighting, make sure to prune its leaves regularly so they don’t get leggy. Giant hygro can grow decently slow under lower light conditions but grows faster under higher lighting.
Bright lighting is required for optimal growth and coloration of leaves, although they are a relatively forgiving plant in terms of light intensity. At least four hours of direct sunlight should be provided each day under normal conditions.
This plant does well in sand or a mix of 50% sand, 25% fine gravel, and 25% peat moss. Hygrophila corymbosa prefers a very soft substrate, with a pH between 6.0 and 6.5. They will adapt to harder water, but it will be necessary to supplement CO2 concentrations at higher levels in order to produce sufficient growth rates.
Despite being a relatively low-light aquarium plant, Hygrophila corymbosa can respond well to fertilization. In some cases, they are better off without fertilizer as they do not thrive in overly nutrient-rich waters. When provided with proper nutrients, Giant Hygro can grow remarkably fast; however, it is vital that you monitor how your nutrient values change over time to prevent over-fertilization. The nitrate levels should remain between 5-10 ppm.
Temperatures should range from 22-28 degrees Celsius (72-82 degrees Fahrenheit). When temperatures rise above 27 degrees Celsius (80 degrees Fahrenheit) or when smaller plants begin displaying signs of sunburn, shading or other forms of protective measures must be implemented.
Hygrophila corymbosa is an easy plant to grow and doesn’t require high levels of humidity in order to survive. It’s not a high-light demanding plant, either, but it can withstand higher light intensity without wilting like some other low-light plants. The key is making sure it has plenty of nutrients, which you can easily do with weekly liquid fertilizer or once every two weeks with slow-release tablets.
The ideal humidity range is 40-50% for optimum growth. If your air conditioning and heating are functioning correctly, you’ll already be in a comfortable zone for a Giant Hygro. You don’t need to worry about over watering or under watering either; just make sure you do it on a regular basis so that all of your plants receive their fair share of water.
If you find that your hygros look especially stunted during certain times of the year, it may be because they aren’t getting enough humidity.
Hygrophila corymbosa pruning
Clumps can be pruned after flowering to tidy up any unsightly areas. Sucker stems or pups growing from nodes within 1–2 inches of an outer stem will become new plants. These pups should be removed once roots develop, as it may delay the maturation of the main plant.
Always ensure that some leaves remain on the mother plant to maintain photosynthesis during periods of active growth. This process is known as pinching back: remove unwanted suckers before they take over your plant!
Hygrophila corymbosa grows very quickly in both its Juvenile and adult forms. It’s not uncommon for a 5-gallon specimen to hit 8 inches within its first year of life, especially if provided with ample light, CO2, fertilization, etc. Beyond its initial rapid growth phase in the aquarium, however, it will grow about 1-inch per month for as long as it lives.
USDA hardiness zones
Though native to South Africa, Hygrophila corymbosa can also be grown in zones 8b to 11. In warmer climates, it’s best to grow it as a container plant. In cooler climates, gardeners should protect their plants from cold with a winter mulch such as straw or pine needles. Gardeners may grow their plants indoors if outside of USDA hardiness zones 9-11.
To date, there are no scientific studies documenting toxicity to aquarium fish caused by Hygrophila corymbosa. However, according to Tropica Aquatic Nurseries, all parts of Hygrophila corymbosa contain calcium oxalate crystals which are mildly irritating if swallowed.
The potential for skin contact sensitivity is unknown at present. It may be advisable for aquarists who wish to keep large numbers of specimens in one tank to wear protective gloves when handling these plants.
Pests and diseases
This plant is very resistant to pests, but all aquarium plants are susceptible to diseases. In order to keep your Hygrophila corymbosa healthy for a long time, you need to be careful about choosing water parameters and making sure there are no dead spots on your leaves. If you do happen to get sick plants, it can often be fixed with a 25% water change.
One of your best bets for keeping pests and diseases under control is maintaining water quality, as poor water quality can make it easier for pests to develop. Along with weekly water changes, you’ll want to perform large weekly water changes that involve removing 25 percent of your tank’s total volume. If you’re able to properly maintain a stable pH level (around 7.0 or higher), that helps prevent fish diseases such as ich from developing.