The rubber tree, an ornamental plant that may reach ten feet or higher, is grown for its large glossy leaves. The leaves, often eight to 12 inches long, may be dark green, maroon or variegated with streaks of white, cream, yellow or pink. Rubber trees are fairly adaptable and easy to grow. And they will grow rapidly, provided they have bright, medium light and are not allowed to dry too much between waterings. Rubber plants are considered a good houseplant choice for the beginner.
Mix water-soluble plant fertilizer with tepid water at half the recommended strength, and pour it into the soil around the rubber tree plant, taking care not to touch the leaves with the solution.
Repeat fertilizer applications as described above every three to four weeks, tapering off in the fall as the rubber tree's growth slows.
Give the rubber plant a rest during the winter months by not fertilizing it. Then, as spring returns and the plant switches to active growth, resume fertilizing every three to four weeks.