pond weeds

Pond Weed Control And Treatments

There are many things that can grow in a large pond or lake. Algae is one of the more common things you’ll find but along with that, or in place of it, a pond weed will take root and sometimes take over a pond or water way. Some of these aquatic weeds can be very invasive and the more well established they become the harder they can be to control. In this article we’ll talk about some of the more common pond weeds one might find across North America and we’ll provide some tips on the best ways to control them.

Cattails And Emergent Plants

By definition, emergent plants grow mostly around a pond, in shallow waters or along the shoreline. For most of us around the U.S. the most common of these would be cattails, reeds, Pennywort, or Bulrush. Because they are usually within easy reach, many people try to remove these manually by using a pond weed rake, or with some heavy equipment and often enough this can help keep them in check for a time.

If a pond owner is unable to physically remove the plants then an aquatic herbicide is likely the best option, and this generally goes for any type of aquatic weed as well. Remove them if you can, treatment if you must. A product called Shore Klear, combined with an activator such as Cide Kick is usually recommended to treat emergent plants. Shore Klear is sprayed directly on the plant and is only good for those that extend above the water’s surface. It doesn’t work well with submerged growth, however it is highly targetable and works well on many emergent pond weeds.

The Pondweed Familly

The term “pondweed” actually represents a species of plants that has over a dozen varieties of pond weeds that can be found in large ponds. A few of the more common plants include Curly Leaf, Large Leaf, Clasping Leaf, and Sago. It’s not as critical to determine the variety since treatments are consistent within the entire family. You’ll know you have a pondweed species when you see fairly long, vine like stems, with leaves branching off of them at different spots. Most leaves are long and slender however this can vary a bit. Sago as an example doesn’t have leaves to speak of, and you may only see very small vine extensions coming off the main stem. This type of plant can sometimes grow in water as deep as ten feet if it is pretty clear and you’ll often see it extending to the surface where it will spread out.

Several broad spectrum aquatic herbicides will work well on pondweeds. Aquathol Super K and Hydrothol are both granular products that can be broadcast over the plant growth and will usually work well to control growth.

Duckweed And Watermeal

Duckweed is one of the more obvious pond weeds since it only floats on the surface of a pond. It’s fast growing and can overtake a large body of water pretty quickly. Free-floating blooms of it will be blown by the wind and may move around the surface of the pond. If you look at duckweed closely you’ll see a somewhat flat, pod-like pellet that has several hair like roots coming off of it. In great numbers they may appear to be a solid mass on the water but they are in fact, individual plants that are pulling their nutrient support directly from the water.

A pond may go without having any issues with duckweed for many years, however the plant can come in, while attached to waterfowl and when conditions are right it will bloom, seemingly out of nowhere.

Watermeal is similar to duckweed however in appearance it’s much smaller in size with what appears to be very fine green grains however once again, when these are dense enough they will cover the surface of a pond.

Physical removal of duckweed is sometimes possible but usually the best course to take is to use some type of herbicide to control the plant. These should ideally be applied early on in the growth, before it becomes widespread on a pond. A product called Sonar, which contains a chemical called fluridone is usually suggested for duckweed control. White Cap is another brand. For a more eco-friendly option a new product on the market called Elemna8 may provide desirable results as well.

Waterlilies Are Good But…

Waterlilies add beauty to any pond that they grow in. No question about that. They also can help provide shade and protection for fish, and work to outcompete unwanted plants like algae. However waterlilies are also really good at growing and they can overtake a pond if they are not managed somewhat.

If you find that waterlilies are getting the upper hand there are several things you can do. Manual removal is an option if they’re not too heavy. Apart from that a product called Navigate can be applied to control them. After blossoms have appeared Shore Klear can be used to good effect.

Invasive Plants Include Hydrilla And Water Hyacinth

Of all the pond weeds that may cause problems for larger ponds, there are several that are so invasive, fast growing, and prolific, that they are now creating a number of issues in various states around the country. Water Hyacinth (Eichornia crasipes) for example is a plant that’s actually native to South America. It’s actually a popular plant to add to small ponds and water gardens, however it infested freshwater areas from the east cost to the west coast and is very troublesome in the southeast U.S. in particular. In many cases a non-native species can harm desirable local species as it chokes them out over time.

Other waters which may be used for irrigation or cooling can become infested and clog up systems or in the case of Hydrilla in Texas, some lakes there have become so heavily burdened that recreation and navigation are being restricted.

It doesn’t take much of the plant to get a foothold and since conditions are often ideal in the southern United States, the plants can grow and spread very quickly. Some control measures include various herbicides but there are also trials underway using biocontrols. M. scutellaris is a small bug native to South American that feeds very specifically on water hyacinth and they may provide a non-chemical way to keep the plants in check.

Where invasive plants are concerned, the best option is to limit their spread by simply not introducing them into the area’s water ecosystem. Small pond and aquarium owners who may benefit from the plant need to make sure they are disposed of properly. If they are removed from the pond or tank, be sure they are dead for about two days before disposing or insure that they come nowhere near a water source of any kind. It has shown the ability to survive in water in trash cans or buckets. They should never be dumped live into a a nearby lake or stream as they wil likely infect the water in short order.

Pond Weed Control Tips

Along with the recommendations that we’ve included for various plants, as a general rule it’s best to attempt the treatment of many pond weeds as early as possible in the growing season. Most species don’t grow well in cold or cooler weather and in many parts of the country that may freeze in the winter, the plants will go away entirely only to return again in the spring. Treating as the plant is just emerging will often allow less use of any chemicals simply because the plant may be more isolated, and they tend to be weaker at that time as well. This also tends to be much safer for fish populations because during any treatment where a rapid die off of plants occur there is the chance of oxygen depletion in the water.

It’s also important to clearly identify what the plant is that you have growing in your pond. Ideally you don’t want to guess and just simply start trying to treat it. Many species require specific types of products for the best control. The University of Florida offers a helpful website for aquatic plant identification as does Texas A & M University. Use these resources if you’re not absolutely sure of what you have growing in your pond or lake.

Duckweed And Watermeal Treatments

by Mark

Duckweed is one of those pesky aquatic weeds that can be very hard to control once it get’s up to speed in a large pond. It’s fast growing, durable, and often not controlled by just any old aquatic herbicide or treatment. In this article we want to explore duckweed in more detail and help a pond owner accurately identify it and offer treatment options which may be helpful in keeping it from taking over a pond.

Duckweed Identification

Common Duckweed (Lemna minor) is an aquatic plant that’s sometimes confused with algae. However it’s very identifiable and quite different in appearance that most algae. Duckweed looks like very small, bright green beads or pellets that appear somewhat flattened. You would find several small “roots” extending from the main body of the plant. Duckweed colonizes in masses and will float freely atop the surface of the pond. It’s usually found in very still or stagnant water in pond with ample nutrients to feed it.

As the name implies, duckweed is often transported from pond to pond by waterfall and they often like to eat the plant. In very limited amounts, duckweed, or it’s smaller relative, watermeal, will not pose any problems but when conditions are supportive of it, the plant can grow rapidly and soon cover the entire surface of a pond. Usually it’s best to avoid this if possible because there is a risk of oxygen depletion in the pond is higher. This of course is not good for fish stocks. Having aeration running in a pond will help guard against this issue but it also may be advisable to try and control the duckweed growth before it overtakes the pond.

Duckweed Control Options

Several viable options exist for controlling duckweed in farm ponds and large bodies of water. Choosing a particular method would depend primarily on the size of the pond, the budget a person might be working with, or a person’s personal philosophy as to whether they would choose to use chemical herbicides or take a more eco-friendly route.

Editor’s Note: It’s usually suggested to treat any pond weed as early as possible in it’s growth cycle to get the best results. If a plant growth is well underway, there is a greater chance of oxygen depletion as it dies off following treatment.

One of the most environmentally friendly options for removing duckweed from a pond is to use some type of skimmer which can manually remove the plant from the water. Since duckweed floats well, it is possible to skim most it off and transport it away from the pond. This offers a chemical free and inexpensive method of control, although it may not always eradicate the plant completely from the pond. To get more information on a useful design watch this video on duckweed skimmers.

Other mechanical skimming options exist that are more advanced than a simple rope, however many of these systems are quite expensive and would likely only be a viable tool for pond management companies to use.

In recent years, one of the more popular and widespread treatments for duckweed is Fluridone. This chemical comes in several brand names such as Sonar and White Cap. This concentrated liquid is relatively expensive but about 8 oz of product (at just under $200 retail price) will treat up to a surface area of 1/4 acre. Fluridone inhibits the plant’s ability to produce carotene and limits it’s production of chlorophyll.

Under normal circumstances it’s recommended to treat the entire pond surface and not spot treat with the herbicide. Once treated, usually the plant will die off over several weeks time and one shouldn’t see any regrowth for the remainder of the season.

Up until recently, Sonar and a few other herbicides were about the only solutions for treating duckweed. In some instances, the use of beneficial bacteria has helped keep duckweed under control, but only if the plant has not progressed to covering the pond. Once it’s well underway, most people had to resort to one of the methods mentioned above, or they would simply leave it alone. Once cool weather arrives the plant will naturally die off and disappear.

In the last year or so however a new, organic and non-chemical solution has been developed which is showing great promise with duckweed control. The product is called eLemna8 and it contains various organic products including turpin oil and concentrated enzymes. What’s interesting about eLemna8 is that it effectively helps to dissolve the protective wax coating which is found on the duckweed petal. It then makes the plant vulnerable and it will begin to die off slowly as the enzyme component begins to break the plant down. The process can be sped up by combining eLemna8 with a herbicide, however the amount of chemical necessary for control is usually much less than if it were used alone. After the duckweed has been killed, it’s not a bad idea to add some beneficial bacteria to the pond to help speed up it’s breakdown completely.

So despite it’s natural durability and propensity for growth, duckweed is a plant that can be effectively controlled in various ways. As noted above, and regardless of what method you may choose to use, the best advice is to treat it early, before it has a chance to take over the surface of a pond. Doing so will allow you to treat it safely in regards to maintaining fish health, and you’ll have an easier time at keeping in check with less chemical use and/or manual effort on your part.

Using A Lake Rake For Pond Weeds And Algae

by Mark

Some large pond owners find themselves in a battle as pond weeds and algae attempt to take over their ponds. In spring and summer around most of the U.S. it’s not uncommon to see algae growing well on many waters and pond weeds growing below the surface.

For some time now, the most likely response to dealing with the problem has been to apply either an algaecide, designed to kill algae, or a herbicide which is often better for weed control. These chemicals can contain any number of things but copper is a common ingredient and because of this there is a growing trend to try and move away from such applications.

Environmental awareness is building each year, and with it, pond owners are looking at other options besides chemicals.

One particular tool that’s become popular is the lake rake.

Lake or pond rakes come in different shapes and sizes and most have long handles or rope tie lines that allow for easy retreival of the rake. The teeth on the rakes are normally longer than a standard garden rake and in some cases they may project off both the top and bottom of the rake head. Float attachments are available as well to make them more effective on floating algae or pond scum. By removing the float the bottom can be dragged to remove loose plant and algae material.

They’re very simple to use. Just toss the lake rake into the pond targeting amongst the algae growth and then pull the rake and the accumulated weeds back in to the shoreline. The removed plants can then be put in a wheel barrow or other transport to move them away from the pond.

A lake rake should not be confused with a pond weed cutter which is also another tool that’s growing in popularity.

As the name implies, cutters are intended to remove rooted weed growth at the bottom of a pond . They’re similar in that you throw the device out into the water but then allow it to sink and begin pulling it back in. As it’s drug near the bottom of the pond it will cut through and sever any plants quite low on the stem. Along with the manual versions, there are powered, boat attached models as well. Once the pond weeds have been trimmed, a pond rake can then be used to remove the cuttings. So the two tools work very well together and are often marketed in this way.

Most manual lake weed rakes are fairly affordable with prices ranging from about $70 up to $130. Powered models such as a lake mower will cost up to several thousand dollars in some cases. So there’s a great savings with the manuall models although you have to provide the elbow grease to get them to work.

For those that are looking for a non-chemical option to algae and pond weed control a lake rake may be one of the better options. They have their limits, such as working best around the shoreline and in shallower water, but in many ponds this tends to be a trouble spot anyway so they may fit your needs quite nicely.