How to Get Rid of Cattails in Garden Ponds Naturally 2018
Cattails belong to the genus Typha, which consists of approximately 30 species worldwide, all of which are classified as semi-aquatic flowering plants that typically thrive in marshes and the edges of lakes and ponds. These plants can spread quickly, able to reproduce by dispersing seeds via wind as well as growing from a shared rhizome, or underground stem that is similar to a root.
In some cases, what appears to be hundreds of cattails may actually only be a handful of individuals sprouting from the same rhizome or group of rhizomes. This means that cattails are able to very easily colonize wetland areas, outcompeting many other vegetative species early on. This isn’t necessarily a bad thing, as cattails provide valuable habitat, food, and nesting areas for wildlife and have been found to help naturally remove pollutants from water.
What are the Most Common Cattail Species?
Three Typha species are commonly found in North America – the broadleaf cattail (Typhus latifolia), narrowleaf cattail (Typhus angustifolia), and southern cattail (Typhus domingensis) – but the National Park Service states that only the broadleaf and southern cattails are deemed native. The narrowleaf cattail has become a significant and challenging issue in the Midwest region, particularly within the Great Lakes Basin region of Michigan, Indiana, and Wisconsin. It is not yet known just how it came to North America, though scientists suspect it moseyed its way over with European settlers in the 1800s. As with other cattail species, narrowleaf reproduces quickly. Because it is not native to the region, the flora and fauna in these areas has not yet adapted to be able to keep this plant in check or properly compete with it for space and resources, and so it often chokes out the native plant species along the ecologically unique and critical Great Lakes shorelines. This in turn damages wildlife that depend upon those plant species, and has a ripple effect as many wildlife species in the Basin are migratory and travel around North America and other portions of the world.
What About Cattails in Garden Ponds?
In your garden pond, you may (or may not, depending on your particular goals) desire cattails to be present. As mentioned previously, they do provide habitat, shelter, and food for many creatures, including the fish in your pond, birds, insects, turtles, frogs, and so on. They also provide some degree of natural water purification, soaking up lead, excess phosphorous, other nutrients, and biological waste from the critters that have made your pond home. However, cattails multiply easily and quickly, and so you may wish to either eradicate them completely or take actions to control their spread to prevent them from choking out your pond and its inhabitants.
The Best Ways to Remove Cattails in Garden Ponds (5 Natural Methods)
1) Hand Pulling the Cattails
To safeguard the health and integrity of your pond ecosystem, natural cattail control methods should be explored first. The most straightforward method is to simply pull them out by hand, ensuring that you pull up the white root-like rhizomes as well. Pull slowly from the base so as to not break the plant, since they can possibly sprout from any intact rhizomes. Depending on how many cattails are present, this may be a slow method, and can stir up the sediment in your pond and cause murkiness that could impact your fish. However, the sediment will settle after a day or two and the cattails can simply be tossed aside and will naturally compost back into the earth. The durable reeds could also be used to make mats or furniture, and historically Native Americans ate the tuberous, nutrient-rich rhizomes by boiling them and mashing them up like potatoes. This method is both one of the easiest and safest methods for removing cattails in smaller garden ponds, but may be too much work in large-scale lakes or natural bodies of water.
2) Cutting the Cattails
Another effective strategy is to cut the cattails below the surface of the water with shears or a gas powered tool like an aquatic weed whacker or hedge trimmer, as the water will act to slow photosynthesis and growth by filtering some of the sunlight and reducing oxygen availability. When using this method, make sure to cut in mid to late summer (July or later), as cutting them in May will actually stimulate their growth since they are already allocating most of their energy to spring growth and will simply resprout. Repeat this cutting two or three times, and each year you should see markedly fewer cattails returning. If you have a large number of cattails or they continue to grow faster than you can cut them, we recommend a mix of both pulling (as above) and cutting to reduce their spread. If you simply want to remove them completely, removing the entirety of the root is always the best solution as cutting will just stunt their growth temporarily.
3) Utilizing Pots to Prevent Growth
If you wish to have cattails in your pond but control their spread, you could place them in pots and then position them in your pond – they prefer water that is two feet or less in depth. Ceramic or clay pots work well, but will need to be heavy enough to stay put underwater. The pots will prevent the spread of their rhizomes, though the plants will still reproduce via seed dispersal. Simply cutting off the heads of the cattails before they go to seed (while the heads are still brown) will thwart this. You will have to throw away the heads to prevent the seeds from persisting in the ground, as cattail seeds can remain dormant and viable in the soil for as long as 100 years. With enough annual and persistent cutting of the heads of cattails, along with having them in restricted pots, you should notice much less aggressive spread from year to year.
4) Altering Salinity (Salt Levels)
Fish and Wildlife Service and Department of Natural Resources conducted various studies that found a salinity of 10 parts per thousand during the growing season is enough to kill cattails. With this in mind, you could increase the salinity of your pond by simply placing a salt block directly within the mass of cattails in the spring, or using pond salt solutions, and then removing it once the cattails have died. If you live near a natural saltwater source you could also attempt to flood seawater into your pond or lake.
The obvious downside of this method is that your pond likely contains freshwater fish and plant species, and as such, they will not be tolerant of significant salinity increases. This method is only recommended for ponds and lakes without freshwater fish or significant freshwater plant coverage, as the heightened salt levels will likely kill most species.
5) Freezing and Dredging Cattails
In the event that your cattail population is too extensive for the above methods, you could either completely drain your pond and allow it to freeze over the winter, which will kill the rhizomes, or dredge up the soil to fully remove any rhizomes and slumbering seeds. However, both of these approaches would require you to move your fish and other pond inhabitants indoors or to a different pond, or fully restock your pond the following spring. If you only have a small number of koi, or smaller goldfish, a stock tank can be used to house fish over winter (with proper filtration added) while the main pond system freezes over and dries out during the winter season. Fish can then be added back in Spring after you have re-filled the pond with fresh water and started up the equipment again.
If you have a very heavily stocked pond, you can instead attempt to drain the water down to the level of the cattails, and then manually dig them from the embankments. This still has the problem of leaving seeds in the soil, and will also cause a huge amount of mess in the pond, so fish should still ideally be moved to a holding environment regardless.
I Have Too Many Cattails – What About Chemical Solutions?
If none of the above methods work, there are also comerically available chemical options for cattail removal. Common aquatic herbicides include Rodeo, Aquapro, and Reward. These are designed for large-scale use in lakes, and we do not reccomend them for smaller garden ponds!
Reward is a contact herbicide that must be sprayed directly on the plant and is listed as being quite potent, killing all plant cells that it comes in contact with. Aquapro and Rodeo are both liquid glyphosate herbicides that are systemic, meaning that they are absorbed into the plant and work their way through every part of it, including the roots. Systemic herbicides act more slowly than contact herbicides, but are more effective as they impact the plant’s entire system and will thus kill the whole plant, rhizomes and all. In any case, make certain that you are using herbicide that is listed as aquatic, as these are designed specifically for aquatic plants. In many areas, it is illegal to use non-aquatic herbicides in aquatic environments, and in others you may need to obtain a permit from an agency such as the Department of Environmental Quality to apply the herbicide. Regardless, always do your research before utilizing chemicals!
Will Aquatic Herbicides Kill My Fish & Plants?
As you might suspect, any chemical designed to kill something has the potential to adversely impact other organisms as well. This could include directly killing both plants and animals, causing sterility and birth defects in animals, making them sluggish and sick, damaging other plants, bioaccumulation in your pond’s inhabitants and other wildlife that visit your pond (which then travel to other areas and may be consumed by predators, leading to further bioaccumulation), and even leeching into the surrounding soil and water table if your pond is not lined. In addition, cattails that die will need to be manually removed from the pond. If left, the process of decomposition will lead to excess nutrients in your pond and deplete oxygen, which in turn may harm your fish and fuel algal growth.
Due to this, for use in garden ponds, we feel aquatic herbicides should always be a last resort – especially if you have fish! If your pond isn’t lake-sized, you should be able to control cattail growth sufficently with the natural methods outlined above in this article, without harm to fish, plants, or wildlife.
Pond consultant and long-time hobbyist who enjoys writing in his spare time and sharing knowledge with other passionate pond owners.