What Are the Causes of Curly Wilted Leaves in Houseplants?

Pests

• There are several houseplant pests endowed with needle-like mouthparts for sucking plant sap. As leaves loose sap, they can become deformed, curled and wilted. Soft-bodied and pear-shaped, aphids feed on new leaves and buds. The damaged, developing growth is usually curled and deformed. Thrips are tiny, winged insects that can be seen jumping around on leaves when disturbed. Their feeding causes leaf tips to curl, wither and die. Mites, like spider mites and cyclamen mites, are often too small to spot, but their damage is evident. They cause yellowed, spotted and curled or deformed leaves.

Cultural Control

• Most houseplant pests can be controlled without the use of harmful insecticides. Mix 1 or 2 tsp. of mild, unscented liquid dish soap in 1 gallon of water and use a spray bottle to spray the solution on plants. A simple jet of water from a spray bottle may also be effective for pests like thrips and aphids. For mites you can soak a cotton ball in a solution of half water and half rubbing alcohol and gently wipe the leaves. Test a small area first to ensure your plant is not sensitive to the alcohol. Prune out severely infected leaves and stems to stimulate new growth and keep any fallen plant matter out of the pot.

Insecticides

• If an infestation is severe enough and cultural control is not effective, you may need to use insecticides. Which insecticide you use will depend on your plant and which pest you have. Always read insecticide labels carefully to ensure you are using one that lists both your pest and your plant and that you're using it properly. Improper use of insecticides can also cause leaves to curl, wilt and turn yellow or brown. Chemicals that are too strong for the plant can burn and curl tender foliage. Insecticides can also settle in the soil and affect plant growth, causing stunting and thick or curled leaves. If the pot is small enough, you can cover the dirt with your hand or a paper plate with a hole in the center for the plant and dip the entire plant upside down in water to rinse off excess chemicals. Large plants may need to be hosed down or wiped off with a soft cloth. For chemical-saturated soil, flush the pot with clean water for two or three minutes.

Under-Watering

• Water is one of the key elements giving a plant structure. Water-filled cells exert outward pressure and keep the plant upright. A dehydrated plant loses its structure and leaves may collapse, curl and wilt. One of the best ways to prevent under-watering is to learn about your plant. It may be a tropical or semi-aquatic plant that needs extra moisture. And the best tool in your arsenal to prevent under-watering is your finger. When you walk by your plant, stick your finger in the dirt. If it is dry down to the first or second knuckle, water the plant. If it isn't, wait a day or two and check again.