Rubber plant care: bright light, steady conditions, and branching

A tropical fig tree in a living room

Ficus elastica (Moraceae) is native to the monsoon forests of northeastern India, through Myanmar, to Malaysia and Indonesia. In the wild it becomes a 30 m tree, often starting life on another tree and sending down aerial roots. Its thick, waxy leaves are built for bright canopy light, and the milky latex that gives it its name seals wounds.

Indoors it tends to grow as a single straight stem, because the growing tip suppresses the buds below it. Like most figs, it reacts to sudden change by shedding leaves. Three rules follow: give it strong light, keep conditions steady, and prune if you want a bushier shape.

Light, temperature, and stability

Aim for 10,000–20,000 lux: close to an east or west window, or 1–2 m back from a south one. Once acclimated over 1–2 weeks, it handles a few hours of morning or winter sun. The variegated cultivars ‘Tineke’ and ‘Ruby’ need the top of that range to keep their cream and pink; in low light their new leaves come in greener. Below about 2,500 lux, any rubber plant stretches, makes smaller leaves, and drops its lowest ones.

Keep it at 18–29 °C (65–85 °F) and above 12 °C (54 °F). Cold drafts from an opened door, air conditioning, or a winter window cause sudden leaf drop, and so does the heat blast from a radiator. Ordinary indoor humidity of 40–60% suits it. Choose its spot carefully and then leave it there; a plant that loses a few leaves after a move needs time, not a new watering plan.

Watering, mix, and feeding

Water when the top 3–5 cm (1–2 in), roughly the top quarter to third of the pot, is dry. In a large floor pot, push a skewer 10–15 cm deep, because the surface dries long before the core. Water until 10–20% drains and empty the saucer within 30 minutes. Clean the leaves with a damp cloth every month or two; dust cuts the light they receive, and leaf-shine products clog the surface.

Use quality potting mix with 25–30% perlite or fine pine bark, in a heavy pot that will not tip as the plant grows. Repot every 2–3 years in spring, 2–5 cm wider, or 5–8 cm for a large specimen. Once it is in a pot over 30 cm, replace the top 3–5 cm of mix each spring instead. Feed every 2–4 weeks from spring to late summer with a nitrogen-leaning foliage fertilizer such as a 3-1-2 ratio.

Pruning, notching, and propagation

Cutting the top off about 1 cm above a node in spring removes the hormonal brake from the buds below, and one to three of them will break into branches. Notching, a shallow 2–3 mm cut into the stem just above a dormant bud, interrupts that signal locally and can wake a single bud without removing the top. Wear gloves: the latex irritates skin and eyes. A damp paper towel pressed on the cut stops the bleeding.

Tip cuttings 10–15 cm long with two or three leaves root in water or moist perlite at 22–27 °C (72–81 °F) in 3–6 weeks. For thick stems, air layering works better: wound the stem, wrap it in moist sphagnum and plastic, and roots form in 4–8 weeks.

Diagnosing leaf drop and other problems

Leaf drop is the symptom owners notice first, and the pattern tells you the cause. Look at which leaves fall, whether they are green or yellow, and how wet the mix is, then change one thing at a time. A plant that has lost leaves from the base up will not regrow them there; pruning is the way to get new growth lower down.

The ASPCA lists the rubber plant as toxic to cats and dogs. The latex irritates skin and eyes, and chewing causes vomiting and drooling, so keep the plant and its prunings away from pets and children.

• Healthy green leaves dropping suddenly: shock from cold, a draft, or a move
• Lower leaves yellowing, then dropping, with wet mix: overwatering and root damage
• Lower leaves curling and dropping with a dry pot: underwatering
• Brown bumps on stems and midribs, sticky honeydew: scale; treat with horticultural oil
• Small corky bumps on leaf undersides: edema from irregular watering in cool conditions