Dwarf umbrella tree

Identification and origin

Heptapleurum arboricola belongs to the ginseng family, Araliaceae. Long known as Schefflera arboricola, a name still widely used in the trade, it is native to Taiwan and the Chinese island of Hainan. It has naturalized in Florida, Hawaii, Jamaica, and Bermuda.

In the tropics it is an evergreen shrub or small tree 10–24.5 ft tall. In a container indoors it usually stays between 3–6 ft, which makes it a long-lived houseplant.

Its palmately compound leaves carry seven to eleven leaflets arranged in a circle at the end of a long leafstalk, like the spokes of an umbrella. The leaflets are obovate to elliptic, thick, bright green and glossy, and 2–4 in long; young plants have fewer of them. Tiny red flowers in branched clusters appear in summer in tropical climates but rarely indoors. They are followed by round berries about 0 in across, orange turning black when ripe, which are not edible.

Several cultivars are common: ‘Gold Capella’, ‘Dazzle’, and ‘Trinette’, splashed with yellow or white, ‘Trinette’ being the most popular; ‘Green Gold’, flecked with gold; ‘Variegata’, variegated with a more compact habit; and ‘Pittmans Pride’, a dwarf, compact form.

Dwarf schefflera is also grown as bonsai: older plants can be trained into small trees.

Light

Place it near an east, west, or south window behind a sheer curtain that filters the sun, with three to four hours of bright light a day. Indoors, strong direct sun burns the leaves. It tolerates medium light, but too little light shows up as yellowing leaves and weak, spindly stems. Outdoors in mild climates it grows in sun to part shade and is one of the better shrubs for shady spots.

Watering

Water thoroughly, until water runs from the drainage holes, then let the mix dry about 1 in deep before watering again. Never leave water standing in the saucer. There is no fixed schedule: the drying of the potting mix tells you when to water.

Watch the leaves: leaf drop can signal either a mix that is too dry or one that is too wet. Always check the root ball with a finger before watering.

This species likes high humidity. To raise it, set the pot on a tray of wet pebbles, making sure the bottom of the pot does not sit in the water.

Potting mix

Use a well-drained houseplant mix rich in organic matter, slightly acidic to neutral. The pot must have drainage holes: a mix that drains slowly is a major cause of root rot.

Fertilize regularly during active growth with a water-soluble or time-release houseplant fertilizer, following label directions. A plant that gets less light needs feeding less often.

Temperature

Dwarf schefflera prefers 64–75 °F during the day, with nights staying above 61 °F. Always keep it above 50 °F: a chill causes dead patches on the leaves a few days later, followed by leaf drop. Keep it away from radiators, heat vents, air conditioners, and open windows, since hot or cold air currents damage it.

It can spend the warm season outdoors in a sheltered spot once nights no longer drop below 61 °F. In the ground it is grown in USDA zones 9b to 12b, where it bounces back well after a light frost and tolerates drought once established. It is also moderately salt tolerant, which makes it useful in coastal gardens.

Repotting

Repot the plant when it becomes crowded in its container; this can be done in any season. Use a pot with drainage holes and a good general-purpose potting mix. If you want to limit the plant’s size, combine repotting with regular pruning rather than moving to ever larger pots.

Pruning

Pruning controls height and produces a bushier plant. Cut stems just above a leaf. Pinching stem tips regularly forces the plant to develop more side shoots and keeps it compact. Wear gloves, as the sap can irritate sensitive skin.

Propagation

Dwarf schefflera is propagated by seed, stem cuttings, and air layering.

• Seed and stem cuttings: these are the two recommended methods for producing new plants in quantity.
• Air layering: ideal for a plant that has grown too tall or leggy. About 12–18 in from the tip of a stem, strip the leaves, make two cuts all the way around the stem 1 in apart, and remove the ring of bark, scraping the exposed wood clean. Dust with rooting hormone, wrap the wound in a handful of moist sphagnum moss, then in plastic secured above and below. Moisten the moss if it dries out. Roots appear after several weeks, sometimes several months; then cut the stem below the moss and pot it up. The parent plant usually sprouts again below the cut.

Early spring is the ideal time for air layering, but indoors it works at any time of year.

Common problems

• Leaf drop: overwatering, a mix that is too dry, low humidity, or a chill.
• Dead patches on leaves: exposure to cold a few days earlier.
• Yellow leaves, spindly stems: not enough light.
• Root rot: a slow-draining mix or overly frequent watering.
• Pests: spider mites, mealybugs, and scale insects; check leaf undersides and stems.

The same symptom can have several causes: look at light, watering, temperature, and humidity together before acting.

Toxicity

Dwarf schefflera is toxic to dogs and cats. It contains calcium oxalate crystals: chewing the leaves causes intense irritation of the mouth, lips, and tongue, excessive drooling, difficulty swallowing, and vomiting. The sap can irritate sensitive skin; wear gloves when pruning. Keep the plant out of reach of pets and, if one eats some, contact a veterinarian.