What we call radiator plants are species belonging to the genus Peperomia. They’re not-so-distant relatives of the plants that produce the kitchen staple black pepper. These are heat-loving plants native to tropical and subtropical regions. Radiator plants vary in appearance, though many have small, flat leaves, and thick stems. They’re generally compact plantings, making them good choices for indoor gardening, hanging baskets, containers, and greenhouses.
It is commonly agreed that they received their common name from American horticulturalist Liberty Hyde Bailey, who—according to Charles Bixler Heiser in his 1985 book Of Plants and People—dubbed the species belonging to the Peperomia genus «radiator plants.» It’s an apt name, as the plants appreciate warm air and sunlight, though they can tolerate both wet and dry climates.
About Peperomia
Peperomia species are grown for their attractive and vibrant ornamental foliage, which comes in an array of shapes and colors. Often, their leaves are rounded and shaped like hearts, though some have elongated, pointed leaves. Much of the foliage of Peperomia species is bright green, but it can also be striped, spotted, or marbled. Some also produce flowers and berries.
The fuller leaves on some varieties of the radiator plant resemble that of a succulent. In fact, these fleshy leaves mean the plant can retain water. There are more than 1,500 types of Peperomia, and the main attraction is their foliage, with a wide choice in leaf shape, texture and color.
Peperomia Species
Popular species of radiator plants include Peperomia argyreia (P. sandersii), also known as watermelon peperomia, which has red stems and rounded leaves that are green and silver. They also produce green flowers. Peperomia caperata is known by the common name emerald ripple peperomia, and it produces white flowers, pink stems, and waxy green leaves. Peperomia obtusifolia (a.k.a baby rubber plant) has deep green foliage that’s oval-shaped and can be marbled with white, in the case of P. obtusifolia «Variegata.»
Peperomia Care
These plants are easy to grow indoors, and most won’t grow over a foot in height. They don’t take up much room, and they don’t need very attentive care. Provide your radiator plants with medium to full sunlight and occasional watering. A good rule of thumb is to water your plants once the soil has dried out completely (it should feel dry to the touch). They’re fairly drought tolerant, and they grow just fine without any interference from fertilizer.
Most radiator plants are slow growing and will only need to be repotted every 3-4 years. Use a peat-free house plant compost, and pot up your plant in a container one size bigger than its current pot. Avoid going up too many sizes, as water retention in the excess compost can lead to root rot. It’ll need an extra inch around the root ball to adjust to the new pot properly.
Help Your Peperomia Thrive
Radiator plants are considered easy houseplants to grow. They are for the most part pest resistant, but pests need to be treated as soon as they appear with weekly sprays of neem oil and regular wipe-downs of the infected plant.
Be sure to stay on the lookout for other plant problems while caring for your radiator plant. If for instance, you witness the plants leaves become dull or fading, it is being exposed to too much direct sun. Is your radiator plant wilting along with the potting mix feeling dry? In this case, the plant is under-watered. Should you see wilting accompanied by leaf loss, this is a result of overwatering.