Looking for a small houseplant that grows into a neat, rounded mound all on its own? Meet Peperomia ‘San Marino’, a compact hybrid with grey-green leaves and red flower stalks.
Peperomia is a big group. The genus has over 1,000 species and belongs to the black pepper family, Piperaceae. Don’t worry, this is not the family that gives us bell and hot peppers. Peperomias are related to black pepper (Piper nigrum), but the ones we grow as houseplants are not edible.
The wild species come from tropical and subtropical Central and South America, Africa, Southeast Asia and parts of Australia, though narrower accounts give their native range as Central and South America. Many grow as epiphytes in the forest understory, using other plants for support without harming them. San Marino itself is a much newer arrival: it was bred in the Netherlands.
Peperomia San Marino Quick Care Tips
- Botanical name: Peperomia hybrid ‘San Marino’ (U.S. Plant Patent PP29,565)
- Parents: an unnamed Peperomia marmorata cultivar crossed with an unnamed Peperomia peruviana cultivar
- Family: Piperaceae (black pepper family)
- Size: about 8.5 inches tall and 12.4 inches wide in the patent’s 35-week-old test plants; slow growing
- Light: bright, indirect light; no direct sun
- Water: let the soil dry out between waterings; never leave it sitting in water
- Temperature: keep it warm, above 50°F, and away from cold drafts; a warm room of 65 to 86°F is ideal
- Humidity: average home humidity is fine; a humidifier helps in winter
- Soil: well-drained houseplant or cactus potting mix
- Fertilizer: occasional low-strength liquid feed in spring and summer only
- Propagation: leaf cuttings
- Pets: most peperomia are considered pet-safe; San Marino is not listed by name
Peperomia San Marino Care Guide
Size and Growth
San Marino grows as a rosette with a flattened globe shape. The U.S. plant patent describes 35-week-old plants grown in 15 cm (about 6 inch) pots in a Dutch greenhouse at 21.5 cm tall and 31.5 cm wide, roughly 8.5 by 12.4 inches. It rates the plant’s vigor and growth rate as low, so expect slow, compact growth.
The patent names two traits that set San Marino apart: grey-green leaves with green veins on the upper surface, and red peduncles (the stalks that hold the flower spikes). The leaf undersides are red. On the patent’s test plants, each glossy, oval leaf was about 1.5 inches long on a leaf stalk a little over 2 inches long.
Its closest look-alikes, according to the patent, are Peperomia ‘Eden Rosso’ and ‘Napoli Nights’. Eden Rosso’s upper leaf is green with darker green veins and its flower stalks are a lighter red; Napoli Nights has greyer upper leaves and pink-red undersides.
Flowers
San Marino’s flowers come on thin spikes. On the patent’s greenhouse test plants, each spike was a little over 4 inches long and carried about 750 tiny flowers with no petals and no fragrance, each only about 0.4 mm across. Don’t count on blooms at home, though: NC State Extension says that, as houseplants, peperomias typically will not flower.
Peperomia flower spikes form in spring and summer. They are considered unattractive and said to resemble a rat’s tail, and removing them lets the plant put its energy into leaves. Some owners like the spikes; others prefer to remove the peperomia flowers. Either is fine.
Light
Bright, indirect light suits San Marino best. Place peperomia where it gets indirect light from an east- or south-facing window; it can even tolerate somewhat low light near a large north-facing window. In general, peperomias prefer bright indirect light yet will tolerate low light. (Not sure which way yours face? Here is a guide to east and west-facing windows.)
Keep it out of direct sun: if peperomia gets direct sun, the leaves may scorch. Variegated peperomias stay more colorful in higher light, but San Marino is not variegated: its leaves are grey-green with green veins.
Temperature and Humidity
Peperomias like it warm. The nickname “radiator plant” refers to their preference for warm conditions, so protect them from cold drafts and keep them above 50°F. For peperomias in general, the RHS gives a warm room of about 65 to 86°F (18 to 30°C) and says to keep them always above 50°F (10°C).
If you summer your plant outdoors, wait until night temperatures are consistently 60°F or higher, start it in deep shade to acclimate, and then keep it in a bright but shady spot out of direct sun.
Average home humidity is fine. Peperomias can thrive in the humidity levels of most homes; if the home is very dry, a humidifier helps, especially in winter. Skip the daily misting, though: fungal leaf spots can be prevented by keeping the leaves dry, so avoid wetting the leaves.
Watering Peperomia San Marino
Here is the one rule that matters most. Peperomia prefers to dry out between waterings, and if it is overwatered, it will drop its leaves. Advice for the closely related baby rubber plant (Peperomia obtusifolia) puts it simply: it is best to err on the dry side when growing peperomia.
Check the soil with your finger before you water, and water only when it has dried. Then water, let the pot drain, and put it back in its saucer. Never let the pot sit in standing water.
Fertilizing
Go light on the food. Fertilize peperomia only when it is actively growing in spring and summer, using a low-strength liquid fertilizer occasionally during the growing season. Another option is a slow-release granular fertilizer once a year. Skip feeding in fall and winter, and follow the label for the amount.
Shop: Jack’s Classic 20-20-20 fertilizer
Soil, Pots and Repotting
San Marino needs a mix that drains fast. Use a well-drained houseplant or cactus potting mix, or add perlite and/or orchid bark to a commercial potting mix so water drains quickly while enough moisture stays behind. Clay pots work better than plastic because water can escape through the porous sides.
Repotting is rarely needed. Peperomia does not need repotting every year and can stay in the same pot for several years, because it is slow-growing. When you do move it up, choose a pot only slightly larger than the grower’s pot. Always use a pot with a drainage hole.
Grooming
Trim off old leaves when needed. To make a plant look fuller, prune a stem just above a leaf node so the plant branches.
Propagating San Marino Peperomia
The patent says San Marino was first propagated by leaf cuttings in 2014, and leaf cuttings are the method it lists. Under greenhouse conditions of 18 to 20°C (about 64 to 68°F), cuttings began to root in about 10 days in summer and 14 days in winter, and took about 80 days (summer) or 100 days (winter) to become a rooted cutting.
The leaf-cutting method for peperomia is simple:
- Remove a healthy leaf with at least an inch of the petiole (leaf stem).
- Insert the leaf stem into a rooting medium.
- New plants will form at the base of the petiole.
- Once they do, separate them and pot them up.
Peperomias in general can also be propagated by stem cuttings or division, depending on the species. For step-by-step photos, see How To Propagate Peperomia Plants.
Peperomia San Marino Pests and Diseases
Watering is behind the most common peperomia problem. Clemson Extension says root rot is caused by overwatering and is the most common disease of peperomia. Root rot and yellowing or curling leaves indicate overwatering, and a plant with yellowing leaves can be saved by letting it dry out, if the yellow leaves are noticed soon enough.
Dropping leaves? Look at watering first, since overwatered peperomia drops its leaves. Fungal leaf spots are another problem; they can be prevented by keeping the leaves dry when you water.
Insects are only occasional visitors. Mealybugs, spider mites, fungus gnats, scale and whiteflies are the pests most often found on peperomia. The patent, for its part, notes that disease and pest resistance has not been observed in San Marino.
If you find mealybugs on a houseplant, UC IPM suggests hand picking or pruning them out. For serious problems on houseplants, it says to dab them with a solution of 70% (or less) isopropyl alcohol and water, testing a small part of the plant first and watching for leaf burn. Be aware that sources differ here: UF/IFAS Extension lists alcohol as phytotoxic (it can burn leaves) and advises against applying it to plant tissue. Insecticidal soaps, horticultural oils and neem oil applied directly to young mealybugs can also reduce their numbers. More tips: controlling mealybugs on plants.
Is Peperomia San Marino Safe for Pets?
Most likely, yes. Most peperomia are considered safe for pets. The ASPCA lists several peperomias, including the baby rubber plant (Peperomia obtusifolia), as non-toxic to dogs and cats. San Marino and its two parent species are not listed by name, so it is still wise to keep it where pets and kids can’t chew on it. If you think a pet has eaten something harmful, call the ASPCA Animal Poison Control Center or your local veterinarian.
Suggested Peperomia San Marino Uses
Small peperomias make good “personal plants,” in the University of Missouri‘s phrase: ideal for small pots, dish gardens and terrariums, where you can enjoy them up close. Peperomias are perfect plants for a desk or tabletop. San Marino’s low, rounded shape fits all of these, and the patent rates it for pots as small as 7 cm (under 3 inches).
One naming note: you may hear peperomias in general called “baby rubber plants,” but that common name belongs to Peperomia obtusifolia. Read more in our baby rubber plant care guide.
Where Did Peperomia San Marino Come From?
San Marino is a hybrid. According to its U.S. plant patent, breeder Obed Jacob Smit crossed an unnamed Peperomia marmorata cultivar (the seed parent) with an unnamed Peperomia peruviana cultivar (the pollen parent) in 2013 in Sappemeer, the Netherlands. He grew the seedlings and selected San Marino as a single plant in 2014, and it was first propagated by leaf cuttings that same year.
Eden Collection BV filed the U.S. plant patent application (No. 15/330,454) on September 22, 2016. The patent, USPP29,565, was granted on July 31, 2018.
Care For Other Popular Peperomias
- Peperomia Rosso Care
- Baby Rubber Plant Care: Peperomia obtusifolia
- String Of Turtles Care: Peperomia prostrata
Give San Marino bright, indirect light, let it dry out between drinks, and leave it in its small pot. It will reward you with a tidy grey-green mound for years. Do you grow San Marino or another peperomia? Tell us which one is your favorite!
Frequently Asked Questions
How often should I water Peperomia San Marino?
Water only when the soil has dried out. Peperomia prefers to dry out between waterings and will drop its leaves if overwatered, so it is best to err on the dry side. Check the soil with your finger rather than following a calendar, water when it is dry, let the pot drain, and never leave it sitting in a saucer of water.
Does Peperomia San Marino need direct sun?
No. Give it indirect light from an east- or south-facing window, because the leaves may scorch in direct sun; peperomia can tolerate somewhat low light near a large north-facing window. San Marino’s leaves are grey-green with green veins; it is not a variegated plant.
How big does Peperomia San Marino get?
It stays small. Its U.S. plant patent describes 35-week-old test plants in 15 cm pots at 21.5 cm tall and 31.5 cm wide, about 8.5 by 12.4 inches, with a flattened globe shape and a low growth rate. Peperomias typically grow 8 to 15 inches tall and wide.
Is Peperomia San Marino toxic to cats and dogs?
Probably not. Most peperomia are considered safe for pets, and several peperomias, including the baby rubber plant, are listed as non-toxic to dogs and cats. San Marino itself is not listed by name, so keep it out of reach of pets that chew plants, and call your veterinarian if you are worried.
Why is my Peperomia San Marino dropping leaves?
Check your watering first. Overwatered peperomia drops its leaves, and root rot from overwatering is the most common peperomia disease. Plants with yellowing leaves can be saved by letting them dry out, if the yellow leaves are noticed soon enough. Let the soil dry and make sure the pot drains.