Sticky Leaves on Houseplants? These 3 Tiny Pests Could Be the Cause

We all want our houseplant leaves to be lush, lovely, healthy, and vibrant. But sticky? Nobody wants sticky leaves on houseplants! While the problem may be family members spilling soft drinks on your plants, don’t bet on it. The most likely cause of sticky plant leaves is sap-sucking insects.

Pests like aphids, scale insects, and mealybugs secrete a sugary waste called honeydew that leaves foliage feeling tacky to the touch. The stickiness builds up on the leaves and can also spread to furniture, walls, and floors near your plants. Houseplant problems like this are annoying, but can usually be resolved if the infestation is not too severe.

If you find sticky leaves on your favorite houseplants, just follow these simple tips below to identify the exact cause and find out how to treat it.

Do Sticky Leaves Hurt Plants?

All of these sap-sucking pests leave behind a clear, sticky liquid waste called honeydew. Sticky plant leaves can happen overnight. If there is a large infestation of insects, it can seem as if the leaves become covered with honeydew in short order.

A little sticky honeydew won’t harm the plants, but it is a signal that you have a serious pest problem. You may have heard that insects like aphids won’t kill a plant, but a lot of piercing-sucking activity can weaken a houseplant. You’ll want to act quickly to prevent more damage to your plants.

Honeydew will make your plant leaves sticky, but it is not toxic to the plant. On the other hand, too much honeydew can invite sooty mold to grow on the leaves. Sooty mold is a fungal disease that can limit plant growth and block sunlight. The best way to control this is by controlling the insect pests creating the honeydew. The first step of proper pest control is identifying the pest.

Common Causes of Sticky Houseplant Leaves

Pests are the main cause behind sticky houseplant leaves. Some insects pierce the leaves and stems of plants to suck out and consume the sweet juices.

There are three different types of indoor plant pests that can leave a sticky residue on leaves. Aphids and scale are among the most common houseplant pests, but mealybugs can also impact indoor plants.

Let’s take a look at how to identify which pest is causing sticky leaves on your houseplants and how to get rid of each one.

1. Aphids

Aphids are small, soft-bodied, pear-shaped insects. They have long legs and long antennae that are commonly green or black. They can also be yellow, brown, or red depending on what they eat.

Aphids reproduce quickly when it is warm. The females give birth to live nymphs without any interaction with males. In fall, the species returns to sexual propagation. The females lay eggs that overwinter on plants.

Aphids tend to attack tender new growth, not strong mature leaves. This can cause yellowing houseplant leaves and stunted leaves and a general weakening of the plant.

2. Mealybugs

Mealybugs are so small it’s hard to see a single one. They can be as small as 1/10 of an inch, but in a group, they look like cottony white masses. These are easy to see on foliage.

The mealybug life cycle starts with egg laying. A female lays up to 600 eggs. She usually lays her eggs in a cottony substance. Look for the eggs in the area of a plant where a leaf meets a stem. In a very short time – a matter of two months – the eggs hatch and the new mealybugs are themselves ready to lay eggs.

Mealybugs can cause stunted growth, discolored leaves, and premature leaf drop.

3. Scale

Scale insects are the most common cause for sticky houseplant leaves, but they don’t actually look like insects at all. They appear as tiny bumps that are tan, brown, or black in color and look kind of like seashells. Scales attach themselves to plant foliage to feed.

They look like small bumps or domes on plant stems or underneath leaves. These bumps are often mistaken for bark because they don't move. But really those bumps are the insects’ hard outer shells that are impervious to insecticidal soap.

These tiny insects latch onto your plant and suck out its moisture, excreting it as a sticky substance called honeydew. Scales won’t necessarily harm your plant, but a large infestation can stunt growth and the honeydew can get everywhere. It’s best to get rid of them if you can.

Their life cycle includes the egg, nymph, and adult stages. Scales are notoriously difficult to control. You might need to toss out houseplants that are heavily infested. But there are a few control methods to try first.

One way is suffocation. Apply horticultural oil, which you can get on Amazon, to the plant. It won’t get through the scales’ armor, but it will stop them from breathing through it.

Another option is to dissolve the scales’ armor. Using a soft cloth or cotton swab, apply 2 tsp (9 ml) of dish detergent mixed with a gallon (3.5 L) of water to the plant, then wipe it again with clean water.

Alternatively, apply a small amount of rubbing alcohol on a cotton swab. Try to wipe away as many scales as possible without harming the plant. You may have to repeat this process every couple of weeks to get all the insects.

If the infestation is heavy, follow up with a routine spray of insecticidal soap, which is available online from Amazon or at your local nursery. Be sure to lay a piece of plastic wrap over your plant’s soil before taking any action, otherwise you might just knock some scales into the soil and prolong the infestation.

How to Fix Sticky Leaves on Houseplants

Now that you know how to identify the pests attacking your plants, it’s time to delve into houseplant sticky leaves treatment. Here are some simple steps to follow, regardless of which pest is impacting your plants:

1. Look for the pests. Where there is honeydew, there are pests, and you need to find them. Inspect your houseplant’s foliage as well as any furniture near the plant. Focus on the parts of the plant that are covered with honeydew, since that is an indication of pest activity.
2. Prune out infected foliage. Prune any leaves that have brown or yellow edges. Curling leaves should also be removed.
3. Give the plant a strong shower. Take the infected plant outside and spray it with a strong jet of water from the hose. Be sure to hit the upper side of the leaves and the underside with the stream.
4. Clear pests and honeydew off leaves. Get rid of pests by dabbing them with cotton swabs dipped in rubbing alcohol. Then wipe the leaves clean of any honeydew. A cloth dampened with very warm water should do the trick for cleaning houseplant leaves. This method can be applied to sticky furniture as well as sticky plant foliage.
5. Use insecticidal soap. Insecticidal soap will kill any insects you haven’t been able to locate. You can find insecticidal soap online from Amazon or at your local nursery. Spray the entire plant once, then repeat a week later.

Houseplant Cleaning Essentials