8 Popular Houseplants That Are Prone to Disease—Plus Tips for Keeping Them Safe

Here's a word of caution before welcoming any of these plants into your home.

There’s nothing worse than pouring love, attention, and TLC into a houseplant only to have it mysteriously die the second you forget to water it precisely at 4 p.m. or whisper it sweet nothings before bedtime. All jokes aside, curating a thriving plant collection can be hard , especially when you factor pests and diseases into the equation.

“Every plant collector will come across pests and diseases in their plant journey, but there are certain things you can do to prevent—or at least minimize—the risk,” says plant pro Krystal Duran, founder of the blog Plants with Krystal. “As a general rule of thumb, make a routine of trimming dead leaves, wiping down foliage, and keeping up with your watering and fertilizing.”

If you’re too tender-hearted to risk a dead plant, there are certain houseplants that are more susceptible to disease that you may want to avoid. Below, we’re detailing the most popular disease-prone houseplants out there, as well as warning signs you should keep an eye out for—and what to do if you find yourself with a sick plant.

Meet the Experts

• Krystal Duran , plant expert and founder of the blog Plants with Krystal
• Paris Lalicata , head of plant education and community at The Sill
• Lisa Eldred Steinkopf , plant expert and founder of the blog The Houseplant Guru
  

Philodendron

“Many species of philodendron are very susceptible to leaf spot diseases,” says Paris Lalicata, head of plant education and community at The Sill. “Signs of disease include scattered leaf spots that spread and may enlarge to form larger necrotic areas. It’s best to prune off any infected leaves and follow up with a fungicide to prevent the pathogens from spreading.” To avoid disease altogether, Lalicata recommends plant parents maintain proper airflow, keep the foliage dry, and avoid misting or splashing water onto the leaves.

Monstera

Due to the nature of the large leaves, Monstera plants can be like candy to thrips. Depending on the stage of the thrips, Duran says they may be seen as small black specks (at the adult stage) or yellow or green oval-shaped larvae.

“Thrips damage initially shows up as yellow streaks on the leaves or stems, then progresses to yellow and brown spots on the foliage," Duran says. "Thrips do fly, so isolating the plant from others or treating plants nearby is very important. Use a strong blast of water to knock off any thrips that are visible, then repot the plant if feasible." Since thrips thrips lay eggs inside the tissue of the plant, Duran says repeating the process of removal is required to win the battle against them.

Prayer Plants and Calatheas

A popular choice for indoor plant enthusiasts, prayer plants and calatheas require a bit of extra attention when it comes to their choice of H2O. “Plants in the Marantaceae family, such as prayer plants and calatheas, will show signs of distress if watered with water containing fluoride, experiencing what we call fluoride toxicity,” says Lisa Eldred Steinkopf, the pro behind The Houseplant Guru. “While chlorine will dissipate if water is allowed to sit overnight, fluoride will not, so, when watering these plants, use distilled water or rainwater.”

Peperomia

Beware: Adorable peperomia plants can be hiding something very sinister beneath the surface of their soil. “Peperomia are susceptible to root rot disease,” says Lalicata. “This occurs under the soil at the roots and is usually caused by overwatering. Signs of root rot include a foul smell coming from the soil, rotting roots, and parts of the plant becoming mushy (particularly the base of the stems). To treat this issue, Lalicata recommends removing the plant from its planter, pruning off any dead or rotted plant material, and repotting the plant into a sterilized planter with fresh soil. “You can also soak the roots in a fungicide before repotting to remove any pathogens or use it as a soil drench after potting,” she adds. “To avoid the disease altogether, make sure you’re only using clean, sterilized pots and avoid overwatering by letting your Peperomias dry out and provide bright light.”

Hoyas

Commonly referred to as wax plants, hoyas are actually an entire genus of plants—and nearly every varietal has to contend with mealy bugs. “Mealy bugs can show up as small cotton-like insects that hide in the crevices of the plant’s foliage or underneath the soil in the roots,” says Duran. “The plant may look wilted, with leaves that are discolored and sticky, and may also have trouble growing. The new leaves that are emerging may look oddly shaped and fall off prematurely.” To treat mealy bugs, Duran recommends blasting off any visible bugs with a strong stream of water, then pruning back any heavily infested areas. You can also use insecticidal soap on the entire plant, and should always isolate it from the rest of your greenie collection to avoid the spread of disease.

Dracaenas

There is such a thing as too much love and attention when it comes to house plants, and too much (or too frequent) water almost always manifests itself in the form of disease. “Dracaenas often develop brown spots on the edges and tips of their leaves, which is a sure sign of fungal disease,” says Steinkopf. She recommends treating the plant with a fungicide or neem oil until the disease is under control and allowing the soil to dry out completely in between waterings.

Alocasias

Beloved for their eye-catching leaves, alocasias will also show the first signs of pests and diseases on the very part that makes them so desirable. “Spider mite damage can show up initially by small scratches to the surface of the leaves,” says Duran. “As the infestation continues, very thin and delicate webbing can be seen all throughout the undersides of the leaves, along with small translucent or red spiders that are hard to see to the naked eye.” Duran goes on to explain that spider mite damage can cause leaves to drop, turn yellow, or wilt, noting that getting an infestation under control quickly is the most important thing you can do to help your plant. "Use a strong blast of water to knock off any visible webbing and mites, then spray a horticultural oil or an insecticidal soap on the top, undersides, and stems of plant foliage," she recommends. "Wipe the plant clean and isolate it from other surrounding houseplants, continuing treatment weekly until the mites are gone.”

Begonia

“Begonias are susceptible to powdery mildew, which is a foliar disease that causes white powder-like patches on the leaves and stems,” says Lalicata, who notes that this disease often develops when plants are drought-stressed or in an environment that has hot days and cool nights. “Signs of disease include powdery-white patches and distorted growth. To treat your plant, improve its environmental conditions and your watering schedule (avoid letting your begonias’ soil remain too dry for too long), prune off any infected leaves or stems, and spray the plant with a fungicide to control the disease.

Related: How to Revive a Dying Houseplant—and When It’s Time to Say Goodbye

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