Water wisteria (Hygrophila difformis) is a fast-growing plant popular for keeping ammonia, nitrates, and nitrites under control. It’s well known for providing shelter for scared fish and fry as well as a spawning site for egg scatterers. What you probably don’t know about water wisteria is that it’s also been shown to keep cyanobacteria (aka blue-green algae) at bay and has anti-microbial properties.
In its native habitat in India, Bangladesh, and Nepal, it has a reputation for taking over rice patties and is considered a weed. It’s also been naturalized in Taiwan and is considered an invasive species in the majority of Southern United States. It’s thought that water wisteria became invasive in Texas due to aquatic plant nurseries or careless dumping by aquarists. In either case, Texas is sure the aquarium hobby is to blame for the invasion – so be sure to properly dispose of any aquarium plants, fish, and products!
It can grow quite large in the aquariums, reaching heights of 2′ and close and 10″ across – large enough to fill a 20 gallon once fully grown. This plant is shade tolerant but prefers medium to high light conditions. Under low light conditions, it’s unable to take up Co2 to and starts consuming oxygen instead of producing it. But, all in all, it’s a hardy beginner plant that deserves a spot in your aquarium.
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How long does it take to grow?
Water wisteria commonly experiences melting problems, so expect to give it at least a week before you start seeing growth. Once it starts growing, it grows as much as 2″ to 3″ per week. That would be almost 1/5th” (over 1/4 a cm) per hour if you were wondering.
Is water wisteria a low light plant
Can you float water wisteria?
Water wisteria can be grown either planted or floated. In either condition, it displays something called heterophylly, which means that the leaf shape changes based on the environment. So it’s common for somebody to mistake floating water wisteria for a different plant than planted water wisteria since the leaf shape differs.
Water Wisteria Care
Propagation: Cuttings and plantlets
Fertilizer: Liquid (NOT root)
Speed of growth: Fast
Temperature: 70 to 82F (21 – 27C)
It grows best in water between 70 to 82F (21 – 27C) with a pH from 6.5 to 7.5, though it likely can go higher. It likes the KH to be between 2 to 8. Water wisteria grows best with minimal water movement if it’s planted – if it’s floating it doesn’t seem to mind water movement, but it won’t grow as fast.
Somewhat surprisingly, it grows best planted in sand but propagates best in gravel. When grown in gravel, the mother plant will produce plantlets, and as these plantlets develop the mother plant will quickly deteriorate. You’ll need to plant these new plantlets and repeat the cycle. When grown in sand, the mother plant won’t produce as many plantlets and won’t start producing them until it’s larger and can afford to spend the extra resources on propagation.
Since water wisteria doesn’t absorb nutrients through its roots, a nutrient-rich substrate isn’t needed – despite popular belief – and, again, it prefers sand anyway. This species does, however, utilize liquid fertilizer and appreciates the addition of liquid carbon if you can – though neither are needed. Co2 also isn’t needed, but it will certainly help your plant grow faster if you find that it’s not growing fast enough for you.
It does best in medium to high light conditions, although it’s tolerant of low light conditions as well – it will start consuming oxygen if there’s not enough light. In their natural habitat, water wisteria will usually flower sometime between late Spring and early summer. The flowers can be blue, white, pink, or bi-color. Though it’s rare for flowers to appear in your aquarium, if it does, rest assured you don’t need to do anything. Once the flower dies, snip it off so the rot doesn’t spread to your plant.
No living thing is without its share of problems, though water wisteria has relatively few. The biggest issue I’ve seen comes down to the misconception that they’re root feeders. Though they can take up nutrients through their roots, they’re not good at it and will only do it if they absolutely need to. Again, they are not root feeders – they’re column feeders and nutrients in the soil do little for their growth.
While rapid plant growth is a great thing in most cases, it can also become a problem when it comes to regular upkeep on trimming, nutrients, and excess plant disposal. Since fast-growing plants usually present an issue for local waterways and most are considered to be invasive species, taking care to properly dispose of excess is incredibly important.
In addition, it’s quite possible that it can choke out your other plants by out-competing them for nutrients. This can, of course, be remedied by changing the water more frequently, adding more fertilizer to the water, or keeping up on trimming of the faster-growing plants. But, since trimming and disposal also comes with its own issues, this last option is probably the most time-consuming.
Plant debris in your tank is a relative problem. If you’re a breeder, your fry and shrimplets will likely enjoy picking off the infusoria and other critters that munch on decomposing plant matter. Similarly, if you have snails, this issue will likely never amount to much. And, so long as you’re not a neat freak, this issue probably won’t bother you.
However, if you don’t fall into one of those three buckets, the mess will probably infuriate you. Additionally, it may cause water quality issues as the plant decomposes and leaches everything it absorbed back into the water.
Clogging Your Filter
Funny thing; aquarium filters. They don’t need large particles to clog, just a lot of small particles. Of course, large floating masses of plants will also clog them.
So as your plant multiplies, sheds, or decomposing plant matter turns into mulm and particulate matter, eventually all of it makes its way to – as you probably guessed – your filter! No matter your filter type; sponge, canister, hang on back, sump, you’ll likely have to up your regular maintenance schedule n your filter.
Melting is incredibly common in aquatic plants as most of them are grown above water. If you pluck off the dying parts of the plant before they start rotting, the new aquatic growth should appear soon enough, and it’ll do just fine.
Maintaining water wisteria isn’t hard. It can do with or without fertilizers, but it does need at least moderate lighting. The great thing about water wisteria is even in high light conditions it’s been shown to keep algae at bay. One major concern with water wisteria is that it grows so rapidly that other plants have to fight for the chance to grow. Since it grows so tall (for an aquarium), it’s capable of blocking out almost any plant it shares a home with.
This is especially true if it’s floating, it could easily take over the top of your tank and prevent most light from getting through. Keeping up with growth is arguably the most difficult part of owning it. You’ll regularly need to thin it out if you have other plants in the aquarium to ensure that it doesn’t choke them out.
If you want your aquarium to look neat and tidy, this probably isn’t the plant for you. Leaves are known for breaking off or forming new gangly roots underneath, which can make it look scraggly. Additionally, disposing of water wisteria is important – even if you don’t live in a climate where it can become invasive. The proper disposal of excess plant material can be a timeconsuming chore.
Propagation of water wisteria is incredibly easy. You can either cut a piece of the stem and plant it or leave it floating. The leaf clipping will grow new roots within a few days and start producing upward growth within a few weeks. It’s important when you plant these guys to keep them a fair distance from each other since they’ll fill in. Their leaves are known to get upwards of 4″ across and these plants capable of growing 10″ wide, so leave room for extra growth.
If you chose to leave it alone, the mother plant will produce plantlets without your assistance. Each new plantlet will grow inside of the mother plant. When you want to thin it out, you have to remove the plantlets from inside the mother plant. When doing this, I found it easier to keep the plantlets and toss the mother because the mother plant tends to look leggy after you remove the plantlets.
Benefits of Water Wisteria
It’s thought that the phosphorus produced by this plant makes it impossible for cyanobacteria to get a foothold. Beyond that, it also has anti-microbial properties that are shown to prevent harmful bacteria as well as the fungus is from getting out of control in your tank. And since it grows so quickly, most algae species will struggle to establish in your tank as well.
The rapid growth also helps take up ammonia, nitrites, and nitrates – which goes a long way in keeping your water cleaner for longer. Water wisteria is also highly versatile – floated or planted, low flow or moderate flow, a wide temperature range, and can be planted in almost any substrate. But, overall, my favorite thing about water wisteria is that it offers a maze of hiding places for fry, skittish fish, spawning sites for egg scatterers, or territory dividers for territorial fish.
Further Reading & Resources
USDA – Weed Risk Assessment for Hygrophila
difformis (L. f.) Blume (Acanthaceae)
– Water wisteria
NCBI – Water-Wisteria as an ideal plant to study heterophylly in higher aquatic plants.