The rubber plant, Ficus elastica. needs little introduction as it is undoubtedly the best-known tree-like houseplant The beat current variety is the large-leaved Ficus Elastica Robusta, which is a great improvement over Ficus elastica Decora, itself an improved variety introduced after World War II.
All rubber plants of this type need a temperature in the region of 13°C (65°F) to thrive, and good light while remaining protected from direct sunlight. Excessive watering is the main reason for failure, so allow the root system to dry out a little between watering.
Most rubber plants are allowed to grow as stately single stems, but it is not difficult to make large plants bush out into a more tree-like shape. When they are about six or seven feet high, cut off the growing point with a sharp knife to encourage the development of side-shoots. While the roots are confined to a pot it will take anything from 10 to 15 years to produce a reasonable rubber plant tree. But given better conditions, with more room for root growth, development would be more rapid.
It is wishful thinking to expect similar tree-like results from any of the variegated rubber plants that are sometimes available. They are both more tender and slower-growing than the all-green varieties. However, given reasonably light, warm conditions and provided watering is particularly careful, there are three variegated types that can do well indoors. They are the varieties Doescheri, whose leaves have light and dark green patches, ivory edges and (in young plants) a pink tinge; Schry-veriana which is the easiest to grow and has cream-edged leaves with cream and dark green mottling; and the all-too-rare Tricolor, which has leaves mottled with yellow, pale green and dark preen. All these tend in time to develop brown mark, along the leaf edges, and there seems to be no treatment.
Other large-leaved Ficus
Of the other large-leaved members of the fig family, the easiest to obtain are F. benghalensis (the bengal fig or banyan) and Ficus lyrata (the fiddle-leaf fig). The latter is much more popular, having large leaves shaped like the body of a violin. But it is also the more difficult to care for in average indoor conditions. A temperature of not less than 19°C (66°F) is needed, and the growing position should be shaded from direct sunlight.
The same may be said for Ficus benghalensis, which is a very strong growing plant that will attain tree dimensions in as little as four years, given good conditions. A drawback with this plant is that the leaves (rather like a rubber plant's in shape) are covered in a natural downy
material that gives them a permanently dusty appearance. Spraying the leaves with white oil used at a rate of three to four fluid ounces to one gallon of water will greatly improve their appearance.
The Moreton Bay fig (Ficus macrophylla) and the peepul tree (Ficus religiosa) are not much used by the commercial nurseryman, and are difficult to obtain. These plants are, in fact, at their best when grown as more compact shrubs rather than as large trees. This will entail removing their growing points when they have attained a reasonable height. Loss of some of the leaves during the more difficult winter months is almost inevitable, and will be more marked if the root system remains excessively wet.
Undoubtedly the most popular of all the smaller-leaved ficus trees, Ficus benjamina (the weeping fig) is also the most
easily obtained. It is not impossible to grow this plant to a height of twelve to fifteen feet, although it may take as many years. By this time the trunk will have taken on a silver birch appearance that is most attractive. Oddly enough, as the plant matures and attains a reasonable height, it seems much easier to care for, and will tolerate quite harsh cutting back with no apparent ill effects. By tying a supple young stem down with stout twine, the main stem may be encouraged to grow horizontally; the resulting plant looks particularly effective growing over an indoor pol.