Radiator plants (Peperomia spp. and cvs., zones 10-12) are beautiful and robust plants with many varieties. While their flowers — like those of many houseplants — aren’t much to write home about, their foliage provides seemingly endless options in color, texture, and habit. Radiator plants can be green, variegated, or variegated. glossy or matte; opaque or smooth; and cascading or straight — and the list goes on. This diversity ensures that there is a perfect radiator plant for everyone that can provide the right conditions. Here’s how to make sure they stay happy and healthy all year round.
Indirect lighting is key.
These plants are perfect for new plant parents who answer the question, “How much light do you have?” with a confused silence and a bowed brow. Radiator plants do not like full sun. They can take some morning sun but prefer medium to bright indirect light all day. If you don’t have adequate exposure to natural light, these plants are best placed under grow lights. There are many LED options available that are energy efficient as well. It’s easiest to put the light on a timer (12 hours on, 12 hours off) and forget about it.
Allow the soil to dry out between waterings.
Radiator plants like it hot—hence their common name. They generally prefer temperatures that are 60°F or higher and are fine with average humidity. These plants want their soil to dry out between waterings. You can even add some extra perlite to the soil to facilitate drainage. Water them once a week if they’re dry enough, but if you forget for a few extra days, you’ll be more likely to have a plant to come home to. Radiator plants with thin leaves need more water because they store less in their leaves. A typical type of ripple radiator plant (P. caperata)—cultivar ‘Quito’ pictured above—falls into this category. Radiator plants are not heavy feeders and can give up food without a beat. If you fertilize them at least once a month during the growing season, however, they will reward you with fast, lush growth.
Try these patterns.
With over 1,500 species and over 100 cultivars, Peperomia is a highly diverse genus. Here are some special selections that showcase this incredible variety.
Columnar radiators are visible plants in the plant.
(P. columellazones 10-12).
This excellent, lesser-known selection is one of the truest of all jeans magazines. It grows small columns of leaves that are perfectly smooth on their upper surface. These epidermal windows allow light to enter the leaves. As the stems grow taller, some snake over the edge or bottom of the pot. This radiator plant is best placed on the drying side. It’s about 8 inches long and the same wide, making it perfect for a small space.
Diverse cupid radiator plant cascades such as ivy
(P. Scands ‘Variegata’, Zones 10-12)
With its spreading habit, the variegated Cupid radiator plant is perfect for a hanging basket. It has heart-shaped silver-green leaves that are buttery white and its stems are slightly pink. An epiphytic plant, this radiator plant does not require constant moisture. It can grow to about 3 feet tall, but trim it to maintain the shape you like.
Felted paperface has very opaque leaves.
(P. Ancanazones 10-12).
Felted paperface is one of my favorite radiator plants because its silver-green leaves are as soft as cat ears. It has a slow weeping habit and will grow to about 1 foot tall and slightly wider. Peppers seem to grow a bit faster when kept slightly moist, as in glazed or plastic pots rather than terra cotta. When it is kept on the dry side, its growth is slow.
Common pitfalls to avoid
Learn the symptoms of these problems and how to prevent them.
Overwatering is the most common problem people have with radiator plants. Eliminating this stress can also eliminate many other problems. You can recognize signs of overwatering if the leaves begin to wilt or become softer and darker than usual. If its root system has rotted, it can be difficult for the plant to recover. Check the soil with your finger before watering, and provide a pot with a drainage hole (pictured).
In general, radiator plants do not attract many pests, although some may be prey to certain enemies. Overwatering can cause fungus to grow in the soil, which can attract fungus gnats. Sticky traps are good at controlling these diseases. These plants can also be susceptible to spider mites and mealybugs (pictured) if they are infested by another plant. It’s a good idea to spray your plant with water from time to time, which washes away dust and any insects. Inspect your plants when watering, looking under the leaves for evidence of insects or their food. Symptoms of insect infestation may include brown spots on the leaf surface, yellowing leaves, peeling, or small black spots. Certain pests require specific treatments, but wiping your plant or using an organic product like neem oil will usually take care of the problem.
Elizabeth Worleybird has been growing houseplants for nearly twenty years. She currently works as a grower at a specialty nursery in western Connecticut.