How to Care for Water Wisteria (Hygrophila difformis)

Water wisteria (Hygrophila difformis) is a very popular aquarium plant in the hobby because of its lacy leaves, bright green color, and rapid growth. It requires very little care, but this species is susceptible to melting and losing its foliage when it first arrives (similar to melting Cryptocoryne). Our top tips and tricks will help you plant your new Wiseria, get over the melting phase, and then propagate it to produce new plants.

What is Water Wisteria and how can it be used?

This aquatic stem plant is native to countries ranging between India and Thailand and can easily grow up to 20 inches tall (51 cm) and 10 inches across (25 cm). (At higher heights, sunlight may have difficulty reaching the base of the Wisteria and the bottom leaves might begin to thin. 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. It is a fast-growing species that can consume nitrogen waste compounds in water to outcompete algae growth. The plant will melt if it isn’t given enough lighting or liquid fertilizer.

Why is my new water not looking like the pictures?

Like many live aquatic plants, wisteria is often grown in commercial plant farms with its leaves and stems out of water and roots in the water. This is a method for growing plants faster and larger, with no pests or algae. Emersed-grown plants, or plants that have been grown above the water surface, generally have thicker stems and larger leaves that can absorb carbon dioxide from the air. Wisteria makes emersed leaves that resemble strawberry leaves. These leaves have an oval shape and grooved veins.

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 look thinner, smaller, and more delicate than their emersed counterparts. Wisteria’s submerged leaves can appear very different from their emersed foliage. This can create confusion. But, they are actually the same species which adapts its leaf appearance 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.

Submersed wisteria leaf (on the right).

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. Remove the stems of the rubber band and bundle the rock wool. 2. Take care to trim any damaged stems and leaves during transport. 3. Use your fingers or tweezers and plunge the base of each stem as far as you can into the substrate. 4. Each stem should be planted separately, approximately 2 to 3 inches (22.5 to 5 cm) apart, so that they can develop roots and become anchored.

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. Wisteria can also grown floating, where it rises to the surface of the water and grows lots of hanging root along the horizontal stem.

Planting water with tweezers in the gravel

Why is my New Wisteria Plant Dying

After you plant the wisteria, expect it to look good for the first couple of days. Halfway through the first week, the emersed foliage will turn yellow and then brown. This is especially true near the base of the 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. Remove the soggy, brown stems and replant healthy green parts of the Wisteria. As needed, add additional lighting and fertilizer.

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. The first submerged leaves may take approximately a month in low tech tanks with dimming lights and no CO2 injection. To speed up this process, use medium to high lighting for the aquarium. Place the wisteria directly in front of the sun and ensure that other plants do not shade it. You can also add nutrients to the water column with an all-in one liquid fertilizer. If you have soft water that has low levels of GH, you may need to supplement it with a mineral supplement. Although CO2 injection is not necessary, it will significantly reduce the conversion time as it provides more building blocks that the wisteria can use.

Plant the wisteria in a substrate and don’t move it. You can stop the ground from growing if it is disturbed. It will then adjust to the new environment and continue to grow for a while. Be sure to not let the stems grow too high above the water. If they do, the plants may produce more emersed rather than 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. You can then plant them again in the substrate once they have established enough roots. Finally, keep the water parameters, lighting, and fertilizer at stable levels because wisteria easily melts when its environmental conditions are volatile.

At Aquarium Co-Op it is our goal to source submerged-grown Wiseria to jumpstart the process and save you all the hassle.

How to Propagate Water Wiseria

Once established, the plant can grow like a weed at a rate between 0.5-3 inches (1-8cm) per day. 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. The bottom half of the stem can be left in the ground and will eventually produce new leaves. 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 lower leaves have developed holes and growth of algae, while the new submerged leaves at the tips are bright and healthy. When several inches of submersed leaves have grown, you can cut off the healthy tips and replant them to replace the old, emersed-grown sections.