8 reasons your pond plants die and what to do

Ponds and aquatic plant life are beautiful additions to any garden, yard, or ecosystem. However, nature is sometimes mysterious, and plants might seem like they’re dying out of nowhere.

Main causes of death for pond plants include imbalance in the ecosystem, low Dissolved Oxygen levels, external factors (such as weather or climate), and misuse of chemicals in water.

Plants are finicky, so its no surprise that they might not be happy in every single scenario. However, reading through these reasons will help you keep your pond plants alive and kicking for a little while longer.

Lack of Sunlight

Sunlight is important. If you learned about the sun in elementary school, you know it provides warmth and necessary ingredients for plants to produce oxygen. Photosynthesis is how plants get their energy, and if they can’t get that, they will start to die.

Plants that are running low on sunlight will look gangly, stretched, and yellow. The leaves will be smaller, flowering plants will stop making flowers, and plants with variegated leaves will lose their spots and turn green.

How did this happen? Well, this should go without saying, but overcrowding can be a serious problem for your pond plants. “Survival of the Fittest” is just as true for plant life as it is for any other organism, and too many plants means too little sun. Plants will overlap one another, blocking the light from reaching their neighbors.

If there is plenty of space for all your plants to get sun, then the problem probably lies in location. The pond might be in a spot that is too shady. In that case, it’s probably too late to solve the problem completely. You can’t just pop the pond out of the ground and place it wherever you want, like you’re living in a video game. So, what to do?

Do research. Find new pond plants that can survive on less sun. Experiment with different plants, finding the ones that look pretty and can stay alive in the shade.

A helpful list of pond plants that prefer shade can be found at this website: https://playitkoi.com/blogs/water-plants/best-pond-plants-for-shadey-areas

Too Much Sunlight

Of course, the exact opposite can be true. Just as some plants can’t handle too little shade, others can’t handle too much sun.

Plants that are overexposed to the sun will start producing a chemical called “zeaxanthin.” This chemical prevents the chlorophyll from producing oxygen, and it burns off as heat to get rid of the extra energy, making the plant even hotter in the sun, causing those burn marks, and killing off sections of the plant until it’s a withered reed.

Signs of a sunburnt plant are bleached colors, wrinkly texture, and plant “burns” (dry spots of yellow, white, or brown that show up on plant leaves). If you start noticing these symptoms on your poor plants, they probably need a little bit of sunblock.

Seriously though, it might be helpful to see if you could possibly relocate the plants to a more shady spot in the pond. Or, put another piece of carefully located décor next to your pond (maybe an umbrella or table), shielding the burnt plants from the sun.

But if all else fails, it might be time to get new plants for your pond. Not all plants can survive in the scorching heat of the Florida summer sun, and that’s okay. Spending a few minutes researching what plants can research what will work wonders.

Here is another helpful site, which has done the research to see which pretty pond plants like as much sun as possible: https://homeguides.sfgate.com/water-plants-small-ponds-full-sun-51244.html

Low Dissolved Oxygen (DO) Levels

Pond plants work so well in ponds because they like to stay mostly submerged in water. However, pond plants, like most life, need oxygen to survive. If the Dissolved Oxygen levels for the pond are lower than 5 mg/L, all life in the pond will struggle to survive.

Since Dissolved Oxygen meters are notoriously expensive (ranging from around $90-3,000), here are some signs to know when your pond is suffering:

  • Fish will spend more time at the surface, searching for oxygen
  • The pond’s water will turn brown or black
  • The fish will stop eating
  • The pond will stink like a rotten egg
  • Weather has been cloudy or extreme (heavy rain or wind)

A solution to this problem could be to get an aerator. An aerator is a device that helps aeration, or provides ways for more oxygen to dissolve into the water. This should help the DO levels to spike in your pond, bringing the dying fish and plants back to life.

Too Much Algae (or Weeds)

Like I mentioned earlier, overcrowding is not a great thing. Plants need the nutrients in the water, and if there are too many other plants in the pond, they will suck up the nutrients. There won’t be enough for everyone.

A good solution to this problem is by adding fish to your pond. Fish aren’t only a great addition visually, but they help balance out the pond’s delicate ecosystem. Fish will eat algae, cleaning up some of those excess nutrient-suckers. Not only that, but the waste that fish produce can serve as excellent fertilizer for your plants.

Another solution that is commonly used is called “aquatic herbicide,” and it’s exactly what it sounds like. Aquatic herbicides are useful for ridding ponds of nuisance weeds, especially when they start killing the plants you actually want there. However, these are very potent and should be used with caution. But more on that later.

Too Many Predators

While you’re using plants in your pond for visual appeal, other organisms see those beautiful flowers, leaves, roots, and they only think one thing: FOOD.

Signals that your pond plants are being eaten should be pretty straightforward. Their roots will begin to be eaten away, and while that won’t be obvious from the top, you can spot your fish in the water, brazenly nibbling at their roots.

Some fish are notorious for ripping apart the pond plants that provide them with oxygen, but they can’t help it. Koi fish are known to eat any water lilies they live with, along with goldfish. The best way to prevent this is to put a barrier within the water between the plants and the fish so fish can’t cross it.

That way, the fish and plants will still be able to benefit off of one another via a symbiotic relationship, and fish won’t be able to use plants as a midnight snack.

If you want your fish and plants to coexist completely, either pick fish that won’t destroy your plants, or plants that won’t be seen as attractive nutrients to your fish. Sometimes, fish just can’t help themselves, and you might just need to replenish your eaten pond plants with new ones every once in awhile.

Improper Chemical Usage

There’s a very good reason that none of the solutions on this list involve chemicals (aside from one). A pond is a living ecosystem–a small ecosystem, but an ecosystem nonetheless. While all chemicals aren’t deadly to plants and fish, it is hard to tell what will be helpful versus harmful. The best solution to this problem is to avoid using chemicals in your pond unless it’s absolutely necessary.

Depending on the size of a pond, using aquatic herbicides at all might kill all life in the pond, including the fish. For more information, this website goes into detail on the best herbicides and how to apply them properly: https://www.solutionsstores.com/aquatic-herbicides

Water is Too Deep (or Too Shallow)

Plants have preferences on the amount of sunlight they like, and the same goes for depth of water. Plants are really opinionated.

Anyway, it’s important to consider what kind of plants you put in your pond when you’re wondering why they’re not doing well. Plants that like deep water should do fine in shallow ponds, but it does NOT work the other way around. Plants that like shallow water will not be able to survive in a deep body of water.

Lotus plants and water lilies love to dive into deeper waters, but cattails and marsh marigolds do much better only partially submerged. Try to pick your plants based on the deepness of water before you purchase them so you’re giving them best opportunity they have to stay alive and beautiful.

Water Disturbances

As mentioned earlier, some ponds might have fountains used as aeration systems to keep the fish and plants happy with enough Dissolved Oxygen.

However, stagnant water is the perfect place for aquatic plants to survive and thrive. Pond plants do great in silent waters, not waters with a fountain that is constantly disturbing their habitat.

Some plants like a little movement, usually the ones that are native to rivers or streams. But most don’t, and the best way to find a solution is to place the plants as far away from the fountain as possible. Depending on how wide your pond is, the fountain could be a good distance away, giving plants the stagnant waters they so desperately crave.

If your pond is on the smaller size, don’t despair. Like I said, some plants enjoy turbulent waters. More hardy plants, such as Dwarf Cattails, naturally survive in streams, so they’ll do well next to a fountain. The solution, yet again, is more research, but when you finally have a nice pond with happy, living plants, it will all be worth it.

Recent Posts