Here at the ranch, we have three main water plants. In fact, these plants are considered invasive and actually banned in some places, such as Florida. This is due to the fact they grow rapidly and can block waterways. However, as are most things in nature, they also present benefits. In this post, I would like to discuss some of the pros and cons of these plants.
Species of Water Plants
Kangkong // Chinese Water Spinach (Ipomoea aquatica)
Kangkong will grow just about anywhere, hence it is considered a water-weed. It is also delicious. It is called different things around the world, such as water spinach or watercress. We introduced this species to the ranch when we found a slow-leak in one of our water tanks. Instead of fixing, we thought we would use it as irrigation! This plant grows incredibly quickly, so we are able to harvest a lot, quite often, and it will grow back before you know it.
In terms of its use – both the leaves and shoots can be eaten raw or cooked. We use it in stir-fries, with garlic, ginger and spicy red pepper. You can enhance the flavor with rice wine vinegar, soy sauce, or sesame oil. Use it like any other green leafy vegetables!
Here at the ranch, we see no downside to this plant – everyone should try growing some!
Water Hyacinth (Eichhornia crassipes)
Not only is this plant beautiful, but it is also edible! As one of the fastest-growing plants in the world, it can double its population in just two weeks! They are edible in a variety of ways. The younger shoots and leaves can be eaten raw, but older ones must be well cooked. They also produce bulbs that can be stir-fried and can taste somewhat like pork rinds. The leaves are very similar in flavor to collard greens.
Water Hyacinth is also nutritionally very dense. It is 18% protein, 17% fiber, and 36% carbohydrates. The flowers can be used as a tonic for horses, by rubbing it on their skin. Be careful, however, as the flowers are toxic to dogs, cats, and horses.
Water Lettuce (Pistia Stratiosis)
As with many water-plants, water lettuce is also highly invasive. If you’re not watching, it will cover an entire pond before you know it. It’s edible (sort of), but will burn your mouth fiercely if eaten raw. Once boiled, it can be eaten without a problem and is eaten in many places suffering from food insecurity.
We have noticed that the fish love to pick around at the root base, probably on algae growing around there.
Gotu Kola (Centella asiatica)
This plant is a popular choice for people looking for medicinal herbs or superfoods. The Kola plant is said to be great for your brain, thus earning the nickname “The Herb of Enlightenment”.
The chemical properties in Gotu Kola help reduce inflammation, and blood pressure. It is used as an anti-bacterial treatment for urinary tract infections, and any common infection. We recommend that people on the farm pick and eat a few leaves every-day when you walk past. It can be a little bitter, but it’s a fantastic natural health boost!
Water plants and oxygenation
People often ask if water plants do a good job of oxygenating the water. The answer is it depends. During the day, they give off oxygen. During the night, however, they actually begin to consume oxygen. They do technically give off more oxygen than they consume, but it is important that their population is managed to ensure maximum benefit.
We recommend that you do not allow water plants to cover more than half of the water surface. This is because they can actually block the surface of the water from absorbing oxygen from the air. Additionally, they help prevent algal blooms from developing in the summer months, as they can shield the water from direct sunlight, which keeps the temperature in the water down.
Here at the ranch, we ‘harvest’ a few wheelbarrows worth a week, which we then use to mix through our compost.
Water plants and prevention of algal buildup
Both the Water Hyacinth and Water Lettuce are great at absorbing excess nutrients from water. These wonderful plants are able to keep the algae levels of water at a healthy level.
This ability also makes them very helpful in greywater treatment. They act as a large, natural filtration process, whereby they are able to absorb toxins and heavy metals from rainwater runoff, or contaminated areas. However, this means that they can be dangerous to eat if the water they grow in is not healthy.
If you have animals, these plants can clean the water before it returns to the surrounding streams and waterways.
Water plants and climate change
As we know, water plants grow incredibly quickly. Due to this, they are very efficient ‘carbon sinks’, which means they do a fantastic job of taking carbon dioxide (gas) from the atmosphere and storing it as elemental carbon (solid).
You can then harvest the plant, and use it as a carbon-rich compost, and return the carbon to the topsoil. This process is a mutually beneficial carbon-sequestering process.
Water plants as compost
Both Water Hyacinth and Water lettuce grow incredibly rapidly, and therefore present great opportunities for compost and mulching.
One challenge that these plants present, is that they are abundant in Calcium Oxylate crystals, which can be toxic to humans. However, Calcium Oxylate is a power alkalizer. Gardeners often use powdered calcium to alkalize their soil, so these water-plants make a great, natural alternative. Not only is it natural, but the calcium in these plants is much a more readily absorbable form.
In addition to using these water plants as compost, we are paying close attention to the plants that grow better in more alkaline environments. Below is a list of the plants that we grow here, that prefer such an environment.
- Arugula (6.5-7.5)
- Bean, pole (6.0-7.5)
- Bean, lima (6.0-7.0)
- Beet (6.0-7.5)
- Broccoli (6.0-7.0)
- Cabbage (6.0-7.5)
- Cantaloupe (6.0-7.5)
- Celery (6.0-7.0)
- Chinese cabbage (6.0-7.5)
- Chive (6.0-7.0)
- Cilantro (6.0-6.7)
- Collard (6.5-7.5)
- Fennel (6.0-6.7)
- Kale (6.0-7.5)
- Kohlrabi (6.0-7.5)
- Lettuce (6.0-7.0)
- Mustard (6.0-7.5)
- Okra (6.0-7.5)
- Onion (6.0-7.0)
- Oregano (6.0-7.0)
- Pak choi (6.5-7.0)
- Sage (6.0-6.7)
- Spinach (6.0-7.5)
- Squash, summer (6.0-7.0)
- Swiss chard (6.0-7.5)
- Watermelon (6.0-7.0)
The amount of calcium is these plants is lower than if we were to use pure calcium. However, the use of water plants does give us a host of other benefits (local, natural, sustainable, and free!). We are currently looking for other ways to integrate water plants into our permaculture setup, such as mulched water plant. If you have any ideas or other uses for these incredible plants, please get in touch!
Water plants and mosquitoes
Finally, a downside to our beloved water plants. They provide a wonderful place for the Mansonia mosquitoes to breed and lay their eggs, so much so, they can be treated as a health hazard. The Mansonia mosquito is large, black or brown in color, with glittery legs. They tend to bite at night, and thankfully do not carry Dengue fever or Zika virus. We do not have a lot of these mosquitos around, and this may be due to the presence of many dragonflies and bats (natural predators).
If in the future we find that we are getting too many of the Mansonia mosquitoes, we may look to build a bat house near the ponds, so they can control the population. We would do this before removing the water plants, as they are currently very beneficial to the farm.
Interestingly, we have been told that Water Hyacinth may actually repel other types of mosquitoes. The owner of Rainsong in Cabuya (Mary Perry) has informed me that she uses the water hyacinth as a natural mosquito repellent in many of her landscaping projects. She has told me they repel mosquitoes, and stop them from laying their eggs in the water.
I must be clear – I have personally not found any evidence of this online. However, I have observed this potential effect at Anamaya. There, we have a body of water that we have planted water hyacinths, and we have not witnessed mosquitoes breeding there. If you have tried this, or have any more information, we would love to know more.