Many people brighten up their backyard pond by planting colorful lotus flowers.
This easy-to-please perennial is uniquely beautiful, forming large, round lily pads that float gracefully on the surface of your backyard pond or water feature.
Without proper care, though, you may see your plant’s leaves turn an unsightly shade of brown.
If your lotus plant isn’t looking its best, we’re here to help. Read on to answer the question: “Why are my lotus plant’s leaves turning brown?”
If your plant’s leaves turn brown outside of winter dormancy, it could indicate you have a more serious health issue on your hands.
There are several common reasons why your lotus’s leaves might be turning brown. Once you figure out the root of the issue, you can focus on restoring your pond to its former glory.
Black Spot Fungus, sometimes called leaf spot fungus or leaf spot disease, is a fungal infection that thrives in warm, wet conditions.
Diplocarpon rosae, the fungus behind the disease, prefers warm, wet weather. Because a lotus spends most of its life in warm pond water, the floating leaves are particularly susceptible to infection.
The first sign of the disease may be too small to notice. The specimen creates a barely visible smattering of black dots along with the leaves, which soon grow larger as they funnel crucial nutrients from the lotus leaves.
If left untreated, black spot fungus will continue to grow and spread, eventually causing the plant to defoliate. Without leaves, your lotus won’t be able to create the energy it needs to stay alive.
Neem oil, a product of evergreen trees, is popular for home gardeners who want to stop Black Spot Fungus in its tracks. It has antifungal properties but isn’t toxic to humans.
Fusarium incarnatum is a species of fungus that can take a toll on your lotus leaves, causing them to wilt, curl, and discolor.
If allowed to go unchecked, this spore will spread from plant to plant, draining your beautiful lotus leaves of their rich coloring and leaving only dead, brown leaves behind.
Trim away the infected leaves and dispose of them safely.
Avoid putting it in your compost bin, as the fungus can live on in the nutrient-rich humus and reintroduce itself to your lotus plants if you use the compost to enrich your pond soil.
When passionate home gardeners picture their perfect lotus pond, it’s probably packed to the petals with plants nestled in tightly together.
While lotus can thrive surprisingly well in cramped conditions, overcrowding could push some of your leaves under the water’s surface.
If a leaf gets submerged under the water, it cannot respirate and will slowly suffocate.
Additionally, your lotus will not be able to efficiently photosynthesize, as the water blocks some of the crucial solar energy these autotrophs need to survive.
Eventually, the leaf will die and begin to rot as it turns from yellow to brown.
Lotus leaves are usually buoyant, but heavy rainfall can force them under the water. Falling dirt and debris such as tree leaves can also weigh down lily pads.
It’s a good idea to check your lotus plants periodically to ensure that the leaves look healthy. If you notice any submerged pads, you may be able to uncover them to prevent browning.
Lotus plants require strong, consistent daily sunlight. However, as with any plant, too much UV radiation can harm leaves.
Because lotus plants grow in bodies of water, they don’t always have shade from trees or bushes overhead.
Water droplets on the surface of leaves can also intensify UV rays. They may even cause sunlight to burn tiny holes through leaves, leaving them vulnerable to infection.
With enough sun exposure, you may see the leaves of your lotus plant dry up and turn brown.
If you notice your lotus plants are getting too much sun, you may want to install a shade structure such as an arbor to protect them. You may also want to consider planting shade trees.
It’s common practice to add extra nutrients to their pond water with water-soluble fertilizer salts.
Fertilizer salts can help lotus flowers grow healthy and strong, but too high a concentration might damage roots and leaves.
When water droplets evaporate from leaves, they leave behind dry fertilizer salts that can burn plant matter.
Fertilizer burn will likely appear as yellow or brown spots on affected leaves. If left untreated, leaves will eventually die and begin to rot.
In some cases, waterborne or non-aquatic bugs may be the culprits behind brown lotus leaves. Several pests commonly infect lotuses, including:
- Waterlily Leafcutter
- Japanese Beetles
- Yellow Striped Armyworm
- Water Lily Aphids
Most pests attack the leaves of plants, though some may infect the root system. As bugs chew on the plant, they can damage tissue and lead to leaf rot.
Using common pesticides on aquatic plants such as the lotus is not advisable. Chemicals can easily make their way into the water and disrupt underwater habitats.
If you have pond life, such as frogs or fish, using pesticides may wipe out the entire population. Instead, use water-safe products or try an alternative pest control solution.
If all other environmental conditions look good, it could be your pond water that is causing brown leaves.
Water needs to be at the right temperature and pH for lotus plants to survive. Chilly water can kill lotus plants, as can a high or low pH.
Nutrient deficiencies may also lead to browning.
Potassium deficiency, in particular, is known to kill leaves starting at the outer edge and spreading in. You’ll notice spots of brown that eventually turn darker as the cells die.
Calcium deficiency is another common culprit, but discoloration is more likely to appear on younger leaves. You’ll see leaf burn at the tip and edges, along with an abnormal curling shape.
Plants tend to hoard calcium when they are first entering the growing season, using it as the masonry to build stable cell walls that help the lotus retain its shape.
Once a young leaf forms under calcium-poor conditions, it will stay misshapen and blemished. It’s better to trim these leaves away and make space for healthy ones to grow.
You can add fertilizer to help correct imbalances, but be careful not to add too much. An excess of nutrients can also shock plants and turn otherwise healthy leaves brown.
Unlike other types of browning, which usually start as individual spots on a leaf, poor water conditions cause necrosis from the base up. Leave it too long, and soon enough, your entire lotus plant will die.
It’s a good idea to test your pond water periodically to ensure it’s safe for your lotus plants.
As the summer transitions into autumn, you should expect your beautiful, verdant lotus to take on a less spectacular appearance as they prepare to bed down for the winter.
Once the hours of sunlight start to get shorter, your lotus will stop directing energy to photosynthesis.
Instead, it will store nutrients in the main rhizome so that it can survive the chilly winter months.
If you want to prune away the unwanted leaves, wait until the first frost and the point at which the leaves are completely brown all the way up the stem.
Healthy lotus stems are hollow, so cutting them back too early allows water to seep into the inner structure of the plant, rotting it from the inside out.
The best way to prevent brown spots on your lotus plant’s leaves is by providing proper care.
Try to keep your pond water at an optimal temperature of around 75 and 87 ℉. The pH should be slightly acidic or approximately 4.5 to 5.5.
If you’re having trouble getting rid of brown spots, you may need to take more drastic measures.
Repotting your lotus plant may help remove whatever chemicals or contaminants affect it.
You should plant flowers in fresh soil and fresh sand if needed. It’s also good to replace old pond water with fresh, filtered water.
Keep in mind that adding water will dilute essential nutrients. You may have to add fertilizer to readjust levels accordingly.
You may want to consider moving your lotus to a new location if it seems to be suffering from UV or insect damage. You can even place your lotus in a pot or planter to grow indoors if necessary.
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If your pond’s lotus population isn’t looking its best, you may be wondering: why are my lotus plant’s leaves turning brown?
Lotus plants naturally fall dormant in the wintertime, leading to brown leaves. However, brown leaves may signify a health problem at other times of the year.
Whether your plant’s leaves are browning due to UV damage or an insect infestation, proper care can have them looking green again in no time
I’m Elsa, and I love gardening. I started GardeningElsa.com as a resource for other gardeners, and I offer expert advice on gardening topics such as plants, flowers, herbs, and vegetable gardening. On my website, I share my latest tips and tricks for creating beautiful gardens. When I’m not working on my website, you can find me in my own garden, tending to my plants and flowers. Read more about me.