Rubber Tree (Ficus elastica)

General information

The rubber tree (Ficus elastica) belongs to the genus Ficus (7) and is considered a classic among indoor plants (1). It was still present in many living rooms and offices until the 1980s. It is making another comeback today (6). In its native East India and Indonesia, the evergreen fig species (5), which belongs to the mulberry family (4), grows between 20 and 25 meters high (3) and its trunk up to two meters thick (2).

At the beginning of the 19th century, the rubber tree (Ficus elastica) came to Europe and North America. As a houseplant, it is especially appreciated for its dark green, coarse and smooth leaves. Like the birch fig and other species of the genus Ficus, the rubber tree secrets a latex-containing secretion from which natural rubber can be extracted in bark injuries. On tropical rubber plantations, however, one finds mainly the rubber tree (Hevea brasiliensis), because it is more productive.

Growth and flowering

Depending on the location and size of the pot, the rubber tree (Ficus elastica) becomes a houseplant about 100 to 200 centimeters high and 80 to 100 centimeters wide. Its leathery leaves, up to 30 centimeters long, are alternate, with entire margins and broad oval with pronounced leaf tips. They have leaf stems two to five centimeters long. Depending on the variety, the upper side of the leaf shines dark green or yellow variegated, the lower silk is light green. The blossom of the rubber tree (Ficus elastica) is rather rare in potted plants. It must be pollinated by the fig wasp to form seeds. The fruit of the rubber tree (Ficus elastica) is a small, yellowish-green oval but inedible fig. If the location is sufficiently bright, the rubber tree forms a broad, branched crown. In unfavorable light conditions, however, the middle drive often branches out only sparsely or not at all.

Location and substrate

The rubber tree (Ficus elastica) prefers light to semi-shade and the warm location at room temperature. The temperature should not fall below 64 °F (18 degrees Celsius) and you should avoid draughts. In summer you can also cultivate the rubber tree (Ficus elastica) outdoors on the balcony or terrace. Here, however, it must stand in semi-shade so that the leaves do not burn.

As an indoor plant, the rubber tree grows to a height of about 3 to 7 ft (100 to 200 centimeters) and a width of 2 to 3 ft (80 to 100 centimeters), depending on the location and size of the pot. Its leathery leaves, up to 12 ft (30 centimeters) long, are alternate, with entire margins and broadly oval with pronounced leaf tips. They have two to five centimeters (0.7 to 2 inches) long leaf stems.

Depending on the variety, the upper surface of the leaves is shiny dark green or yellow with yellow variegation, the underside is light green. The flower of Ficus elastica is rather rare in potted plants. It must be pollinated by the fig wasp to form seeds. The fruit of the rubber tree is a small, yellowish-green oval, but inedible fig. If the location is sufficiently light, the gum tree forms a broad, branched crown. Under unfavorable light conditions, however, the central shoot often branches only sparsely or not at all.

Substrate

Suitable substrates are conventional indoor plant or green plant soil or sandy soil with a high coconut fiber content.

Watering and fertilizing

You should water the rubber tree (Ficus elastica) rather moderately and only when the soil has dried again superficially.

In order to keep the root ball not too moist and to avoid stagnant moisture, it can be useful to completely submerge the root ball in water from time to time until it is soaked up with water.

In spring and summer, you can provide the rubber tree with green plant fertilizer every two weeks. Repotting is useful when the bale is completely rooted.

Cleaning Rubber Tree

Since the leaves of the rubber tree (Ficus elastica) are very large, dust accumulates on them over time, which stands out well from the dark green smooth soil and therefore sooner or later becomes an optical problem.

For cleaning, you can put the complete rubber tree, if it is not too big, into the shower and shower it off. First, put the inner pot together with the root ball into a foil bag so that the soil does not get soaked.

To prevent limescale stains, wipe the leaves with a soft cloth after the shower bath. You can also rub the leaves with a cloth slightly soaked in beer to make them shine again.

Young rubber trees grow quite quickly under good light conditions and should, therefore, be given a slightly larger pot every two years in spring. For old plants, repotting every four to five years is sufficient.

 Propagation

If you want to propagate a rubber tree (Ficus elastica), you have several methods to choose from. On the one hand, it can be propagated by cuttings that can be cut from the side shoots. Then remove all leaves from the cuttings up to the upper one and dry the cuttings slightly again. Cut the cuttings from the top leaf to about six to eight centimeters and then place them in a narrow glass filled with up to one-third water. You should change the water every two days. As an alternative, you can also place the cuttings directly in a pot with slightly moistened growing soil. Then cover the pot with foil or place it in a foil bag. This is closed with clothes pegs and aired from time to time. After about four to eight weeks the cuttings have formed roots in both cases with a little luck.

Rubber trees (Ficus elastica) can be also propagated by cutting. If the tree does not branch out by itself, you can simply cut the middle shoot over a leaf to stimulate the formation of side branches. However, a dense crown only forms under good lighting conditions, i.e. on a large south window or in the winter garden. If possible, cut your ficus outdoors, as the stains of latex can hardly be removed from the carpet and clothing. Only when the secretion has dried well at the interface should you bring the rubber tree back into the house.

In order to rejuvenate old rubber trees and grow a new one, new plants can be obtained by using the leaves of the plant in spring. The prerequisite is that the plant has as many leaves as possible. Under the leaf knot – usually the fourth pair of leaves from the tip – make a horizontal cut through the middle of the trunk with a sharp knife and underneath make a diagonal cut upwards.

Afterwards, you must spread the cut surface with a small wedge or a wooden stick. Around the open cut, place a well-soaked bale of moss, press it against and wrap it in cling film. Bind the moss foil package above and below the notch with some raffia. Roots should form on the wound after about six weeks. Below the interface, you can now remove the rooted shoot tip from the mother plant and pot it into soil rich in humus.

Diseases and pests

The rubber tree (Ficus elastica) is generally regarded as robust against diseases and pests. When pests colonize the plant, they are often mealybugs or scale insects. You can recognize an infestation by the fact that the leaves dry out and turn yellow. As a countermeasure, the rubber tree should be immediately isolated from the other houseplants. Neem oil can help fight plant lice. A mixture of paraffin oil, water, and washing-up liquid, which you spray on the leaves, and showering the leaves have also proven to be effective countermeasures. Very frequently, it is afflicted also by mosquitoes.