Ficus robusta, also known as a rubber plant, is an attractive indoor plant for homes and offices. Native to monsoon climates, the ficus robusta can be grown outdoors in U.S. Department of Agriculture plant hardiness zone 11. The plant has shiny dark green leaves that can grow 5 inches wide and as much as 10 inches long, but some rubber plants have burgundy-greenish leaves. Ficus robusta plants can grow 20 feet tall in a container with proper care.
Place houseplants in a location where the plant will receive bright light for at least six hours a day, but not from southern sun exposure. A sunny eastern or western window will benefit the plant and is not as hot as the southern sun, which is the early to mid-afternoon sun.
Keep the soil moist, but don't overwater the plant. When the soil is slightly dry 1 to 2 inches below the soil surface, water the plant thoroughly and don't water again until the soil is slightly dry. Remove excess water from the drainage tray under the container after the excess water has drained from the plant medium.
Adjust room temperatures to 15 to 18 degrees Celsius at night and between 24 and 26 degrees Celsius during the daytime hours.
Repot the ficus robusta when the plant outgrows the container. Use a container 2 to 3 inches larger with equal parts of peat moss, coarse sand, soil and perlite.
Feed the ficus robusta every four weeks with 10-10-10 -- nitrogen-phosphate-potassium -- water-soluble houseplant fertiliser diluted in half during spring and summer. If the ficus is located in an area with low light, reduce feeding to once every four months.
- Colorado State University Extension: Plant Talk Colorado; Rubber Plant
- Clemson Cooperative Extension: Rubber Plant; Karen Russ, HGIC Horticulture Specialist and Bob Polomski, Extension Consumer Horticulturist; March 1999
- University of Minnesota Extension Service: Rubber Trees, Weeping Figs and Other Friendly Ficus; Deborah Brown; June 2001