In a restaurant my wife and I pass a painting of a pond. It’s nice. “Honey, do you see that on the painting? The flowers are water lilies and the leaves are lotus?” Brooke: “That’s terrible, now can we order an appetizer?” Water lilies, lotuses, and other lily-like plants in our ponds are confused on a regular basis and it happens frequently in artistic renderings, even though they are detailed in their observations.
American White Water Lily or Fragrant Water Lily are common in our ponds and I actually consider them a good addition to a pond. Will they take over? Plants grow and they need management just like the ones in your flowerbed, but they have some advantages. They look and smell nice. The rubbery round leaves float directly on the water and each mature plant can cover an area 3-10 feet in diameter. This makes shade and structure for fish in the form of three-dimensional habitat and cooler water. Water lilies and plants in general break up the monotony of open water. They will grow readily in 2 to 5 feet of water. The flowers are white with yellow centers and attract bees, with a fragrance similar to a gardenia. The flowers also rest directly on the water with the leaves. Water lily is easily controlled with glyphosate with a surfactant. You can select each lily to be treated. Spray one, leave the other, or give the whole patch a haircut around the perimeter. With the advantages of habitat and the ease of control, water lily makes a good addition to the pond.
American Lotus are not a lily. I do not recommend they are added to ponds. A good starter plant can take over 1 acre under 5 feet of depth in a single season. They do make a great specimen plant for a water garden, just not ponds. The leaves shed water extremely well, better than the best wax job on the hood of a car. The leaves extend above the water line up to three feet and can be 18 inches in diameter. The flowers are a medium yellow, up to 8 inches in diameter, and also extend above the water line. When the petals fall off the seed pod develops into a shower head with a rattle of hard seeds inside, a favorite item with florists. If you have an infestation of lotus, you can control them with glyphosate, or 2,4-D but you will need a good dose of a surfactant since the leaves are super effective and shedding water based product. Test your surfactant mix before applying to make sure you will get it to stick on the leaves. Lotus also are fragile in the summer growth stage. A drag or cutting tool through the roots will damage them for effective control, but it is work.
Watershield is a small football shaped water lily leaf floating on the surface of the water. The green leaf is about 2 x 3 inches and underneath it is burgundy colored with a layer of jelly coating it, giving it the nickname “snot bonnet”. The leaf stems are tough and you will know it if you ever run a trolling motor through them. In fact, you are probably still stuck in them while you received this article at your new mailing address in your pond or lake. The flowers are burgundy and about ¾ inch, similar to a honeysuckle. I don’t care for this plant on my ponds although it is good for waterfowl forage. Glyphosate and 2,4-D are moderately effective but imazapyr and glyphosate are much better.
Flouridone is a whole pond treatment that will address all the above plants. It has its considerations. It is a whole pond treatment and there will be no selectivity. It is expensive and can be flushed out. If you have a watershed that flushes the pond, this not the best approach. Application is easy, safe and the chemical is persistent, giving a full season of protection if it is not flushed out.
Hopefully, this helps whether you want to control your pond vegetation or paint it.