How to Care For Water Wisteria (Hygrophila diformis)

Water wisteria (Hygrophila difformis) is a very popular aquarium plant in the hobby because of its lacy leaves, bright green color, and rapid growth. Although it is easy to care for, this species can melt and lose its leaves very quickly once they are purchased. This is similar to melting Cryptocoryne. Get our top tips for planting your new Wisteria, how to get past the melting phase and how to propagate it so you can grow new plants.

What is Water Wisteria and how can it be used?

The aquatic stem plant can grow to a height of 20 inches (51 cm) or 10 inches (25 cm) in countries between India and Thailand. (At greater heights, light has difficulty reaching the base of the wisteria and thus the bottom leaves may begin to thin out.) Many people use this bushy species as a background plant in their fish tanks, but you can also plant it in the foreground or midground if you want to cut it shorter. As a fast-growing plant, it is often used to consume nitrogen waste compounds in the water and outcompete algae growth. However, if you do not provide enough lighting or liquid fertilizer, it will let you know by melting away from starvation.

Why does my new water wisteria not look like the pictures online?

Wisteria, like many aquatic plants, is grown in commercial plant farms. It grows its leaves and stems from water and its roots in water. This is a method for growing plants faster and larger, with no pests or algae. Emersed plants are plants grown above water surface. They have thicker stems, which can withstand gravity, and wider leaves that can absorb carbon from the atmosphere. Wisteria produces emersed plants that look similar to strawberry leaves. They have a 1.5-inch (4 cm), oval shape with grooved veins and slightly jagged edges.

Emersed-grown wisteria leaves

Once you place the wisteria in your fish tank, it must drop its old, emersed leaves and grow new, submersed leaves (or leaves that are grown completely underwater) that are capable of drawing carbon dioxide and other nutrients from the water. Submerged leaves tend to be thinner, more delicate and narrower than emersed growth. Wisteria produces submersed leaves that look drastically different from their emersed growth, which can lead to a lot of confusion, but they are in fact the same species that changes its leaf appearance to adapt to different environments. Wisteria can grow underwater to produce bright green, feathery, and tall fronds measuring 4 inches (10 cm). Its bushy appearance can be used to add an interesting visual texture to planted tanks and is perfect for hiding fish fry or shrimp.

Submerged grown wisteria leaves (on left)

What is the difference between water wisteria and water sprite? Both wisteria and water sprite (Ceratopteris thalictroides) have delicate, lacy leaves that look quite similar, but when compared side to side, water sprite has thinner, more needle-like leaves. Water wisteria can grow long stems, while water sprite creates new shoots at its base.

Submersed-grown water sprite

How to Plant Water Wisteria

1. Take out the stems from your rubber band and wrap the bundle or rock wool in a plastic pot. 2. Any stems or leaves damaged in transportation should be cut. 3. Use your fingers or tweezers to push the stem’s base into the substrate or gravel as deep as you can. 4. To ensure roots develop and anchor the stems, plant them separately at a spacing of 1-2 inches (22.5-5cm).

If you have fish that like to dig in the substrate, protect the newly planted stems by surrounding the patch of wisteria with a ring of rocks, wood, or other decorations. Alternatively, wisteria can also be grown as a floating plant where it simply rises to the water surface and develops lots of hanging roots all along the horizontal stem.

Planting water with tweezers in gravel

Why is My New Wisteria Plant Dying?

After you plant the wisteria, expect it to look good for the first couple of days. After the first week, the emersed leaves will begin to turn yellow, and then brown, particularly near the bottom of their stems. If the leaves turn brown, you can take them out to prevent your aquarium from absorbing rotting organics. The stems of wisteria that isn’t getting enough light or nutrients may become brown and eventually melt. Replant the green, healthy parts of the wisteria by removing the soggy stems. Then add more lighting or fertilizer as needed.

Emersed-grown leaves at the base of the stem tend to brown and melt off first.

How to Convert Your Wisteria from Emersed to Submersed Growth

The conversion phase can take anywhere from a couple of weeks to a couple of months, depending on the fish tank’s light, nutrient, and carbon dioxide (CO2) levels. It may take up to a month for submerged leaves to appear in a low-tech tank that has dimming lighting and no CO2 injection. For faster results, you can use moderate to high lighting. Place the wisteria directly under the light and make sure other plants don’t cover it with shade. Also, provide lots of nutrients in the water column using an all-in-one liquid fertilizer, and add a mineral supplement if you have soft water with low amounts of GH. While CO2 injection does not need to be done, it can reduce conversion times as it provides more building blocks for the Wisteria.

If you plant the wisteria in the substrate, try not to move it around. It will stop growing for a time if you move it around. Then, it will adjust to the new place and grow again. You should also ensure that the stems do not grow too high or out of the water. Otherwise, they might develop more emersed foliage instead of submerged leaves. If your wisteria is not converting, you can try floating some stems so they can receive more light and CO2 at water’s surface. After they have grown enough roots to be able to plant in the substrate, you can replant them. You should also keep your water parameters, lighting, as well as fertilizer stable. Wisteria is prone to melting if its environment becomes volatile.

At Aquarium Co-Op we try to source submerged-grown wisteria in order to jumpstart the conversion and save you the hassle.

How to Propagate Water Wiseria

Once the plant is established, it will start to grow at a rate that is 0.5-3 in (1-8 cm) per daily. To prevent it from blocking all the light and outcompeting other plants, cut off the top half of the stems and replant the trimmings to propagate the wisteria. You can leave the bottom half of the stem in the ground, and it will eventually grow new leaves from the tip. If the bottom half of the stem is too “leggy”, or has lost most of its foliage due to conversion or lack of sunlight, some people decide to remove it and place the top half of their stem. If the wisteria is floating, don’t let it cover more than 50% of the water surface, or else it may shade out other plants and cause stagnant, oxygen-deprived water.

The emersed leaves lower on the stems have developed holes and algae growth, whereas the new, submersed leaves at the tips of the stems are healthy and bright green. Once several inches of submerged leaves have grown, you can trim off the healthy tips and plant them again to replace the emersed-grown portions.