A Ficus elastica is a tree that is more commonly known as a rubber plant. It is native to Southeast Asia, where it can form very large banyan trees. Also known as the rubber fig, this plant is also a common ornamental found all over the world. It is grown outside in tropical and Mediterranean climates, and as a houseplant in cooler climates. While not a source of commercial rubber, the Ficus elastica plant can serve as a source of an alternative type of rubber.
In its native environment, Ficus elastica commonly grows 98-130 ft (30-40 m) tall. It has a wide trunk, up to 6.6 ft (2 m) wide. The tree is known as a banyan because it has aerial roots that grow out and help to sustain the heavy branches. The Ficus elastica leaf is larger on young plants than on older ones. On the young shrubs, the leaves range from 3.9-14 in (10-35 cm) long. In contrast, on older plants, they are generally 3.9 in (10 cm) long.
For use as a houseplant, plant breeders have developed cultivars that are much shorter, to facilitate their use in the home. Some of them have variegated leaves. The leaves of rubber plant houseplants can grow to be 8 in (20.5 cm) or more. These smaller trees generally grow 6-10 ft (1.8 – 3.1 m) tall. They prefer temperatures of 65-70°F (18.3-21.1°C) at night, and 75-85°F (20.2-22.9°C) during the day.
Ficus elastica prefers to receive bright light without being subjected to direct sun. It does well under conditions of high humidity. The plant prefers to have its soil kept constantly moist, although it will tolerate drought. It will not tolerate standing water, however. The rubber tree should either be placed on top of pebbles or have its dish drained immediately after watering. It should not be watered with cold water.
The plants can be left to grow in the same pot for a long period of time, until their growth appears stunted. They should then be transplanted in early spring. General potting soil will be adequate for their growth. Avoid fertilizing plants that have been transplanted or newly purchased for six months. After this, they should be fertilized every six months.
Eventually, Ficus elastica will grow tall enough to reach the ceiling. At that time, it should either be pruned or propagated by stem cuttings or air layering. To prune the plant, one can cut it back to a level close to the soil in early spring. It will grow back quickly.
Propagation by air layering involves making a cut halfway through the stem near the top of the plant. Wrap the cut in moist sphagnum moss that is surrounded with a plastic bag. New roots will form within a few months. Then, one can cut below the roots to generate a new plant. This rubber plant can be transplanted and will form a new tree.