Native to tropical America, philodendrons are easy-to-care-for houseplants that can grow vigorously with the right care. These evergreen perennials just require sufficient water, indirect sunlight, and fertilizer to grow well. A lack of any of its basic needs may cause problems for your philodendron, and certain problems can cause its leaves to turn white or develop white spots.
Here, we will discuss some of the causes of this unsightly leaf discoloration, as well as how to correct the problem.
Common causes of white spots on leaves
There are many possible reasons your philodendron leaves are losing color and turning white. Often, the problem can be difficult to diagnose, especially for novice gardeners. But do not lose heart! Philodendrons are generally easy-to-care-for plants and are very forgiving. Once you begin to understand the underlying causes, there is a good chance you will be able to revive your plant in no time.
Have a look at these common causes below when troubleshooting the discoloration of your plant’s leaves.
1. Powdery mildew
If you notice powdery mildew on top of the leaves, this is caused by a fungus that thrives in humid environments. Philodendrons love humid conditions and slightly moist soil, but so does powdery mildew! These spores usually grow during spring and autumn when the air is humid, then spread to the environment when the air turns drier. If not dealt with promptly, this white substance may damage your plant as it prevents the leaves from functioning correctly.
2. Fusarium leaf spot disease
If you begin to notice brown spots on the philodendron’s leaves, your plant may have Fusarium leaf spot disease, which is also caused by a type of fungus. Sometimes, these spots can also be pale in color and turn the leaves whitish.
Just like powdery mildew, this leaf spot disease can also be triggered when plants are exposed to a humid environment. Moist leaves can also encourage the growth of fungi. Over time, the spores will begin to consume your plant and weaken it, until it succumbs.
3. Cold temperatures
Tropical plants like philodendrons do not do well in cold environments; they prefer a temperature of 65 to 85 degrees Fahrenheit. Anything outside of this range may cause problems for your plants.
When the temperature drops below 32 degrees Fahrenheit, the plant’s leaves will begin to freeze and turn brown, gray, or white. This happens because, without the required warmth, the cellular walls of the leaves collapse and can no longer function properly.
4. Pest infestation
Pests are often inevitable guests on both house and garden plants, and philodendrons are no exception. If you see white fuzzy patches on your plant’s leaves, the culprit could be a pest infestation.
Philodendrons are a favorite of mealybugs, whitefly, woolly aphids, and spider mites. If you do not get rid of them as soon as possible, these pests can spread quickly and affect nearby plants.
Mealybugs, also known as ‘crawlers’, are white, waxy scale insects that are found underneath the leaves and feed on the plant’s sap. When they turn into adults, these white cottony masses can cause severe damage to your plant and also spread quickly to nearby plants.
Whiteflies are sap-sucking insects that can be seen on the underside of the philodendron’s leaves. The nymphs are usually covered in a cottony white powder and resemble tiny moths. Just like mealybugs, these whiteflies can also spread fast if not promptly dealt with.
Wooly aphids are tiny, black, or pink-brown insects that hide under a fluffy white fuzz. Although not dangerous when their numbers are small, they can be a nuisance. These uninvited guests feast on the plant’s juices and produce a honeydew substance that may irritate your plant.
Spider mites are another type of insect you need to watch out for, as they can severely damage your philodendron and spread easily to nearby plants. They can be brown, red, white or transparent in color. Spider mites love feasting on the top layer of the leaves and produce gray or white webs underneath the leaves that resemble spider webs. A philodendron badly infested with spider mites may show compromised health and slowed growth.
5. Lack of sufficient sunlight
Philodendrons with pale or white leaves may simply be lacking proper sunlight. Keep in mind that these plants are native to tropical areas with sunshine and warm temperatures.
However, too much sunlight can also be damaging to them. Never expose them to direct sunlight as this can burn their leaves. Philodendrons grow well in shaded areas where they can have access to partial sunlight.
6. Lack of macronutrients
White or pale foliage is often a sign of nutrient deficiency, especially calcium and magnesium. Both of these are essential nutrients for your philodendron to grow well and photosynthesize, and a lack of them can cause the plant to develop white spots and yellowing of its leaves, also known as chlorosis.
7. Alkaline soil
Many plants, including philodendrons, need slightly acidic soil to absorb nutrients properly. Alkaline soil can hinder their nutrient absorption, and when deprived of nutrients they will develop pale or white leaves.
8. Salt build-up
Plants transpire water through their leaves, and as the water evaporates it leaves a white residue on the leaves. This is a normal process. However, excessive white streaks or granules on the leaves may be a sign of a salt build-up in the soil. Over time, this build-up of salt and other minerals can prevent the plant’s uptake of nutrients and slow its growth.
9. Genetic mutation
Heavily cultivated plants like philodendrons may be susceptible to genetic mutations, known as ‘sports.’ These can manifest as parts of the plant, such as buds or leaves, looking distinctly different from the rest of the plant. You may see some healthy leaves with white spots, or leaves that are totally white in color.
Genetic mutations are beyond your control and do not usually pose any danger to your plant. Some garden enthusiasts even use them to create new cultivars with different characteristics or features.
How to care for philodendron leaves with white spots
It is often challenging to identify exactly the problem behind your philodendron’s pale or white leaves. Different issues require different treatments. Fortunately, there are simple solutions to most of the issues discussed above.
1. Use neem oil to get rid of pests
Neem oil is the best weapon to combat bad infestations. If you think your plant is being feasted on by pests, then a spray of neem oil should be enough to eradicate the unwanted visitors. Neem oil can seep easily into the leaves and stays there for a long time, preventing the bugs from ravaging your plants in the future.
2. Prune the affected leaves
If you see white spots developing on your plant’s leaves, it is best to prune off the affected leaves right away to prevent further damage. Use disinfected pruning shears to cut the leaves off. However, if the majority of the leaves have already turned white, then the disease has likely spread already. In this situation, pruning might not be enough to save your plant.
3. Use a fungicide to treat fungal diseases
Fungal diseases such as powdery mildew can be easily managed using a chemical fungicide. Neem oil may also be used as an effective fungicide. Spray the affected leaves to prevent the spores from spreading any further, and isolate the infected plant to avoid any spread to nearby plants.
4. Make sure your plant gets enough air
Place your philodendron in an area with good air circulation. This can help prevent your plant from catching fungal diseases like powdery mildew.
5. Provide sufficient water
Plants can resist damage and diseases better when they are given the right amount of water. Ensure that the soil is always a little bit moist to keep your philodendron happy, but never overwater it as this can damage the roots and kill your plant.
6. Place your plant in areas with indirect sunlight
Philodendrons thrive in partial sunlight, so make sure you place yours in a shaded area or near a window. Keep in mind that intense heat from the sun can cause sunburn and damage the leaves.
7. Use the correct amount of fertilizer
Fertilizers can give your philodendrons a boost, especially the younger ones. You can feed your plants with high-quality fertilizer once a month during the growing season and every couple of months during autumn. Never apply fertilizer during winter, as this is when your plant goes dormant and does not need the extra nutrients.
Wrapping it up
Philodendron leaves turning white or developing white spots can be unsightly. This discoloration is often caused by fungal diseases such as powdery mildew, but other factors such as pests, lack of sunlight, and overwatering may also play a role. Thankfully, most of these issues can be easily resolved with the right treatment and care.
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