Croton

Identification and origin

Codiaeum variegatum belongs to the spurge family, Euphorbiaceae. It is an evergreen, woody-based shrub native to a wide island region: Borneo, Java, Sulawesi, the Moluccas, the Philippines and the Lesser Sunda Islands, New Guinea and the Bismarck Archipelago, the Solomon Islands, Vanuatu, Fiji and Queensland in northeastern Australia. The genus name comes from kodiho, its common name on the island of Ternate; the epithet variegatum means variegated.

In the wild, its leaves are plain glossy green. The plants sold today are cultivars selected for their variegation: yellow, pink, orange, red, bronze, purple and green, in blotches, colored veins or stripes, and the colors shift as each leaf matures. The leaves are alternate, thick and leathery, 2–12 in long (sometimes up to 18 in), narrow and strap-like or oval, smooth-edged or deeply lobed, sometimes wavy or twisted into a spiral. Milky sap oozes from any broken leaf or stem.

Common cultivars include ‘Petra’, the most widespread, dark green with yellow, pink and orange-red veins; ‘Gold Dust’, green speckled with gold; and ‘Spirale’, with twisted red and green leaves. Indoors it rarely blooms; the flowers, in slender clusters, are inconspicuous.

In its native habitat it reaches 8–10 ft. In a pot it usually stays between 2–4 ft.

Light

Light is the key to its color. Give it bright light with some direct sun: the more light it gets, the more vivid the foliage and the more compact the plant. With too little light, new leaves revert to green and the lower leaves fall. On the other hand, harsh sun can dull the foliage to a grayish cast. Outdoors in summer it handles partial shade or full sun if acclimated gradually and never allowed to run dry.

Watering

Croton has moderate but steady needs. Water when the top 0–1 in of the mix feel dry, then let the excess drain away. During active growth, from spring through fall, keep the mix moist but never soggy. From fall to late winter the plant appreciates a partial rest: water less often, and always check the mix before you pour.

What to watch for: mix that stays too wet or too dry for long periods causes leaf drop. Croton also likes moderate to high humidity; in a heated home, stand the pot on a tray of wet pebbles.

Potting mix

A fertile, well-drained mix rich in organic matter that still holds some moisture. Drainage matters as much as fertility: roots that sit in water eventually rot. During the growing season, a half-strength liquid fertilizer for foliage plants keeps the leaves vigorous.

Temperature

It thrives between 61–84 °F. Days around 70 °F and nights of 55–61 °F suit it well. Below 50 °F it drops its leaves. Above all, it dislikes cold air currents and sudden temperature swings, which send it into shock.

It can spend the warm season outdoors once temperatures stay reliably above 50 °F, provided it is eased into the brighter light. Bring it back in before fall nights dip below that mark. Planted in the ground year-round, it is hardy only in USDA zones 11 and 12, where there is no frost.

Repotting

Repot once the plant has filled its pot, moving up to a container only 1–2 in wider. Like any abrupt change, repotting can cause some leaf drop, so return the plant to its usual spot afterward.

Pruning

If the plant has become leggy and bare, cut it back hard in early spring, before new growth begins: this encourages branching and fresh shoots. Wear gloves: the sap irritates skin and permanently stains fabric.

Propagation

Air layering in spring and softwood stem cuttings in summer both work well. Take cuttings 4–6 in long, strip the lower leaves, then insert them straight into rooting mix or root them in water first. Seedlings do not reproduce the parent’s colors: only vegetative propagation keeps a cultivar true.

Common problems

• Leaf drop: the most common complaint. It follows a move, repotting, a blast of cold air, a cold spell below 50 °F, or mix that has stayed too dry or too wet for a long time. Stabilize conditions and wait for recovery.
• Leaves turning green and lower leaves falling: not enough light.
• Dull, grayish foliage: direct sun too strong for a plant that was not acclimated.
• Pests: spider mites, mealybugs, scale insects and thrips. Check the undersides of the leaves; insecticidal soap or horticultural oil will control them.

The same symptom can have several causes: before acting, check light, potting mix, temperature and signs of insects.

Toxicity

All parts of croton are toxic: its milky sap contains diterpene esters. In people, eating it causes nausea, vomiting and diarrhea, and contact with the sap irritates skin; repeated contact can lead to allergic dermatitis. In dogs and cats, chewing the plant causes mild irritation of the mouth and digestive tract: drooling, vomiting, diarrhea and sometimes skin irritation. Toxicity is low unless a large amount is eaten, but keep the plant out of reach of children and pets, wear gloves when pruning, and if any is swallowed, call a veterinarian or Poison Control.