By Tony Dean
Farmers and ranchers are in a very close partnership with Mother Nature. If we really pay attention, she presents us some interesting scenarios.
For example, though they are totally different types of plants, water lilies and prickly pear have a lot in common. They both have strikingly beautiful flowers, both plants are edible, both of them are invaders into their respective habitats, and too much of either one can be an obstacle that we have to deal with.
Many north Texas ranches rely on excavated ponds for livestock water. Any time a pond contains a significant amount of shallow water so that sunlight reaches the bottom, some type of pond weed will develop. The plant family that includes water lilies and lotuses is a common invader in our livestock water.
Water lilies and lotuses are in the same plant family but they are two separate genera. There are easy ways to tell them apart:
- A primary difference is that water lily leaves commonly float on the surface, but lotus leaves can grow above the water line.
- Water lily leaves and flowers are thick and waxy, while lotus leaves and flowers are thin and papery.
- Water lily leaves have a distinct notch in the leaf, while lotus leaves are more rounded.
- Water lily flower petals are pointed, and lotus petals are more rounded.
The photos attached to this writing are from Clay County, and this plant is common across north Texas. American lotus is adapted to a wide area, from Honduras north through Mexico and across the eastern US and into Canada.
American lotus is a perennial, and it is cold tolerant and heat tolerant. It can grow in any pond or slow moving stream that contains shallow water areas. It prefers water with a depth of about 12 inches. Germination can occur from the large lotus seeds. Tubers, or roots, are established in the mud, and long slender stems extend upward. Leaves and flowers are both emergent in that they grow above the water line.
Lotus flowers are fragrant, and yellowish white with rich gold centers. They open in the morning and close by late afternoon, then open again the next day.
Lotus is an edible plant and has a history as a food source. The large tuberous roots, the size of a human arm, were baked like sweet potatoes. The leaves were eaten like spinach, and the large seeds were ground into flour. Stems taste somewhat like beets and were usually peeled before being eaten.
There is a large world-wide industry of cultivating lilies and lotuses in water gardens. According to Dr. Jerry Parsons, Professor and Extension Horticulturist with Texas A&M AgriLife Extension, cultivation of these plants dates back as early as ancient Egypt. Today, anyone with determination and a little money can have a water garden.
In 2011, the 82nd Texas Legislature designated the water lily “Texas Dawn” as the official Texas State Water Lily. Texas Dawn is a hybrid developed by Texas resident Kenneth Landon, a world-renowned expert in the field of water lilies and the director of the International Water Lily collection in San Angelo.
Ducks and other wildlife utilize the large acorn like seeds of American lotus, and submerged portions of all aquatic plants provide some form of wetland habitat. Many of us have tried to pull a bass out of a group of water lilies or lotuses, and I’m sure others have had better luck than I did. Although there can certainly be benefits to lilies, lotuses, and other aquatic plants, they can also infest ponds to the extent that the pond is not functioning correctly.
So, while the rest of the world works hard to grow these plants, ranchers sometimes need to control populations in their stock ponds. Once it gets a foot hold, American lotus can spread aggressively in wetland areas.
The primary issue that encourages American lotus, and most other water weeds, is shallow water. Look closely at a good livestock pond and you will find that the deeper water is basically free of infestation. Any pond will have a certain amount of shallow water that encourages water weed growth, depending upon the terrain at the pond site and how the pond was constructed. Some ranchers who enjoy and utilize wetland habitat may prefer to have ponds with significant shallow water area.
Almost all livestock ponds have a certain life expectancy. Siltation, or movement of soil into the pond bottom through rainfall runoff, is a natural occurrence. How fast siltation occurs into each pond, and how deep the pond was to start with, determines the length of time that the pond will contain adequate depth for dependable water for livestock.
Ponds that develop infestations of water weeds over a large percent of the surface may not have adequate depth to remain a viable water source for livestock during drought periods, especially in western north Texas where evaporation rates are higher.
Mud, or silt, from the pond bottom, can be removed to deepen the water, but this is a very expensive process. It is often more economical to construct a new pond rather than try to remove the silt from an old one. Most of us do not have the funds to continually construct deep water livestock ponds, so we must try to keep existing structures functioning and providing good drinking water for livestock, for as long as we can. Control of pond weeds like American lotus may be necessary, and it can be accomplished.
There is currently no feasible biological control. American lotus can be cut and removed, but this process us usually temporary because lotus can reestablish from seeds and roots.
American lotus can be safely controlled by chemicals. This must be done carefully. If a pond containing a large amount of any pond weeds is treated to remove all of the vegetation, a fish die-off could occur. When the dying weeds decompose, they use up the oxygen in the water and fish can suffocate. If possible, treat only a portion of the area, wait about two weeks, and treat another portion.