Coleus
Coleus scutellarioides · the Painted Nettle
It grows wild across tropical Asia and into northern Australia, a bushy mint-family plant kept for one reason: leaves in red, maroon, pink and purple, almost anything but plain green. The colour comes from anthocyanins, the same pigments that redden a cabbage or an autumn leaf.
Family
Lamiaceae
Origin
Tropical Asia
In the wild
Flowers all year
Indoors
15–90 cm
Growth
Fast
With pets
Toxic
Where it's from
Southeast Asia to northern Australia
Tropical Asia to Australia
Across Java, Borneo, the Philippines, Thailand, Vietnam, New Guinea and Queensland, at 100 to 1,600 m.
Outdoors: zones 10–11
Grown as a warm-season annual everywhere colder. Frost kills it.
Can escape and persist
It may naturalise in other frost-free tropical regions, though it is not a serious invasive.
It trades green for colour
Coleus colour comes from chlorophyll plus anthocyanins. More light boosts the red and purple anthocyanin and suppresses the green chlorophyll, so the same plant reads greener in shade and redder in sun. It is grown to be anything but green.
Roots in a glass of water
Drop a stem cutting in tap water and it roots in about a week. One of the easiest plants to multiply.
Pinch off the flowers
Its small bluish flower spikes are a distraction. Growers pinch them to keep the leaf colour strong.
A name that won't sit still
It has moved through five genera since 1763. Coleus was formally re-established in 2019.
How to keep it
LightPart shade to full shade
Classic types want shade. Newer sun coleus hold their colour in full sun. Too little light washes the colour out.
WaterKeep evenly moist
Do not let it dry out. It wilts fast when thirsty but recovers quickly. Avoid waterlogging.
HumidityModerate to highTolerates average rooms, but dry air can crisp the leaf edges.
Temperature18–24°CFrost-tender and cold-sensitive. It drops leaves or dies in the chill.
SoilRich, loose, well-drainedMoist, organically rich mix. A peat-free potting compost works well.
FeedingOften in growthA high-nitrogen feed about every two weeks fuels leaf production.
DifficultyEasyOne of the most beginner-friendly plants. Low maintenance.
With petsToxicEssential oils. Vomiting, diarrhea and loss of appetite if chewed. A notable exception among the easy foliage plants.
PropagationStem cuttingsCuttings root readily in plain water. Cultivars do not come true from seed.
RepottingAs neededMany growers treat it as disposable and re-root fresh cuttings each season.
What the data says
What it costs
About as far from a collector plant as houseplants get. Cuttings root so easily that scarcity never builds.
$3–10
Newer patented and sun-coleus cultivars run a few dollars more. There is no four-figure market here.
Not an air purifier
Coleus lands on air-purifying lists on the strength of NASA's 1989 sealed-chamber test, which is nothing like a real room.
100–1,000
plants per square metre would be needed to match a room's normal ventilation (Cummings and Waring, 2019). Opening a window beats a jungle of coleus. Grow it for the colour.
IUCN · Not threatened
In the wild
The opposite of the usual collector tension.
Coleus is so prolific and easy that it is effectively a global garden commodity. The wild species is secure rather than imperilled. The only conservation note is that it can escape and persist in frost-free climates.
When it sulks
Leggy, sparse plantToo little light, or not pinched. Give it more light and pinch the tips.
WiltingDry soil, or for shade types, too much sun. It recovers fast once watered.
Faded, washed-out colourToo little light. More light means more anthocyanin and more colour.
Flower spikes appearingPinch them off to redirect energy into the foliage.
PestsAphids, spider mites, whiteflies and mealybugs. Treat early.
Varieties & company
The varieties
WizardKongInky FingersColorBlazeBlack Dragon
Pairs with · keep apart from
CaladiumBegoniasFernsSnake PlantCactiSucculents
A new plant, every week.
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