Lotus is generally preferred as an ornamental plant, but sometimes the lotus population in ponds or lakes can explode. If more than half of the water is covered with lotus, then you have a problem. The lotus can be removed manually or chemically, but both methods can be time consuming. It is also not recommended to clean all lotuses floating above the water's surface as lotuses usually oxidize the water for fish and provide shade for all underwater aquatic life.
Method 1 of 2: Manually Removing the Lotus
Step 1. Row the boat over the lotus
If this lotus-filled water surface is a large lake or pond, and you want to slide the lotuses out to make room for the boat, just row the boat through the lotus pool. Usually this is enough to pave the way and expose the water surface. The most suitable boats for this method are rowboats instead of motorboats, as the lotus risks getting caught in the motor blades.
Step 2. Scratch the lotus
If the pond is relatively undisturbed and the lotus roots are not too tangled then raking the surface of the pond is a great solution for cleaning the lotuses. Paddle the boat into the middle of the pond or walk to the center of the pond if the water is shallow enough. Use a standard garden rake to pull the lotus off the surface of the water. The tougher varieties usually have firm roots which will make harrowing difficult and you may not be able to pull the lotus from the roots. This method is good as a short term solution, but the lotus will grow back after that.
Step 3. Fill the pond with fish
If the lotus grows in a private pond, just add a few grass carp (if this species is not native to your area, it can be invasive) or other fish that eat water lilies to naturally reduce lotus numbers from the pond surface. Usually, the effective amount is to add two fish per 4,000 m2. Choose young fish because the young will eat more than the old ones.
Step 4. Use a shovel
You can use a shovel if the pool is shallow enough and can be lowered, but difficult for deeper ponds and lakes. While standing in the pond, poke the shovel under the lotus root. Pull the roots out of place, then lift the lotus off the surface of the water. This method will take a long time and may be difficult if the pool is large and you are working alone. However, this method is quite effective and can clean the lotus directly to the root of the problem.
Step 5. Use an aquatic lawn mower
An aquatic lawn mower is a specially designed tool and works like a weed mower, but is useful for trimming weeds and vegetation growing above the water's surface. This tool is usually used to eradicate algae and seaweed, but can also be used to cut lotus. The aquatic lawn mower can be used from a boat so you can use it for both deep and shallow pools.
Method 2 of 2: Chemical Exterminator
Step 1. Apply the chemical after the main flowering season is over
The use of these chemicals is the most effective way and has the least chance of permanently damaging the pond ecosystem after the first flowering season is over.
Step 2. Find out where to apply the chemical
Chemicals are usually applied from the middle of the pool outwards, in a small area in each application. Spraying the entire pond at once will rot many plants and destroy the oxygen that is valuable for aquatic life below the surface of the water. To avoid this, apply the chemical to the areas of the pond where the lotus grows the most, before spraying small areas over the next few weeks.
Step 3. Apply agricultural surfactant
Applying the herbicide directly to the lotus sometimes works, but often you'll need to use a surfactant first to melt the protective waxy coating on the lotus's outer surface. Spray an ample amount of surfactant over the lotus.
Step 4. Choose the right type of herbicide
A glyphosate-based herbicide is the most common type used to kill lotuses, but you can also use an imazapyr-based herbicide. Both are nonselective broad-spectrum herbicides that essentially kill the surface of the plant they come into contact with, but not to the extent of killing plants that live below the surface of the water.
Step 5. Apply herbicide to the lotus surface
Follow the instructions on the herbicide label to determine the correct dose. Typically, aquatic herbicides are sprayed directly onto the lotus until the surface is thoroughly and evenly coated.
Step 6. Scratch the dead lotus
The herbicide will kill the lotus and leave the dead plant floating on the surface of the water. Walk or boat to the pond and rake a dead lotus. Pull out the roots if possible. Even though herbicides have killed root tissue, pond conditions will not be healthy if there are too many dead roots that settle to the bottom and rot away.
Step 7. Repeat this process for a few weeks
Wait two to three weeks for the next application, and spray small areas at a time to keep the pond ecosystem in balance. After the entire pond has been sprayed with herbicide, return to the area that was previously sprayed if the first spray still leaves a lot of live lotuses.
- Use protective gear when cleaning lotuses from ponds or lakes. At a minimum, you should wear waterproof boots and protection when walking into the pond to spray lotus. If you use chemicals, also wear gloves and protective eyewear.
- Find out the regulations in your area regarding the eradication of aquatic plants. Cleaning that violates the rules can get you penalized. If you throw the lotus in a private pond, of course it will not be a problem. However, if you want to eradicate lotus or other aquatic plants in public waters such as lakes, check with your local government for regulations first.