Croton

About Croton

Croton is a tropical shrub from Malaysia, the Pacific islands and northern Australia grown for leathery leaves splashed and veined in yellow, orange, red, pink, purple and green; hundreds of cultivars range from broad ovals to twisted ribbons (NC State, Wisconsin Horticulture). In a pot it usually stays around 3 ft tall and needs more light than most houseplants to keep its color. It is also touchy: a cold draft, a move, or soil that stays too wet or too dry makes it drop leaves, and the milky sap irritates skin and stains fabric for good.

Hardy outdoors only in zones 11-12 (NC State); it is grown indoors everywhere and can summer outdoors in part shade once nights stay reliably above 50 F, coming back in before fall temperatures drop below 50 F (Wisconsin Horticulture, NC State).

When to plant

Timing is counted from your average last spring frost (and first fall frost). Sow & Tell works out the actual dates for your ZIP code.

Usually bought as a nursery plant or started from a 3-4 in stem cutting rooted in warm, moist mix; cultivars don't come true from seed (UF/IFAS, Wisconsin Horticulture).

Growing it indoors

• Light: It needs bright light with some direct sun to keep its color; in too little light the new leaves come in plain green, and in harsh all-day sun they fade gray and dull (NC State, Wisconsin Horticulture, UF/IFAS).
• Water: Water only when the top half inch to inch of mix is dry, soaking it through, and water sparingly in winter (Wisconsin Horticulture, NC State); MU Extension's table says keep it evenly moist. Wilting new leaves mean it is thirsty, but mix that stays wet or dry for long stretches makes it drop leaves (UF/IFAS, Wisconsin Horticulture).
• Humidity: It likes moderate to high humidity; set the pot on a tray of wet pebbles in dry rooms (NC State, Wisconsin Horticulture).
• Temperature: Keep it at 60-85 F and away from drafts and sudden temperature swings, which shock it into dropping leaves; below 50 F leaves fall (Wisconsin Horticulture, NC State).
• Feeding: Wisconsin Horticulture feeds only once or twice during the growing season, more often for faster growth; MU Extension's general rule is about once a month while new leaves are coming and none in winter.
• Repotting: Repot when the roots outgrow the pot, moving up only 1-2 in in diameter into fresh well-drained mix (Wisconsin Horticulture).

Soil

A fertile, humus-rich, well-drained potting mix in a pot with a drainage hole (NC State, Wisconsin Horticulture).

Pot in a fertile, humus-rich, well-drained potting mix in a container with a drainage hole (NC State, Wisconsin Horticulture).

Feeding

• Spring through summer, while new leaves are coming: balanced water-soluble houseplant fertilizer. Wisconsin Horticulture feeds once or twice a season, more often for faster growth; MU Extension's general rule is about once a month, watering first and never feeding a wilted plant.
• Winter: none. Skip feeding and water sparingly while light is low (NC State, MU Extension).

Don't repot or feed a plant that is dropping leaves; fix the drafts, light and watering first (Wisconsin Horticulture).

Varieties (15)

Pests to watch for

Twospotted spider mite, Mealybugs, Scale insects, Thrips

Diseases and problems

Root and crown rot

In the kitchen

Safety: All parts contain diterpene esters: eating a lot can cause nausea, vomiting and diarrhea (NC State, low severity), and the milky sap itches and swells soft tissue, can cause an allergic rash with repeated contact, and permanently stains fabric, so wear gloves, wash your hands and keep it out of your eyes (NC State, Wisconsin Horticulture). Keep children from nibbling the leaves (UF/IFAS).

Pets: Not listed by the ASPCA. NC State lists it as poisonous to people (diterpene esters, low severity) and UF/IFAS says to keep pets from nibbling the leaves.