The rubber tree or rubber plant is the common name of the species Ficus elastica, commonly grown as a houseplant. The rubber plant grows well in a variety of conditions and is easy to care for, according to Karen Russ and Bob Polomski of the Clemson Cooperative Extension, concluding that it is an excellent choice as a houseplant. One problem with your rubber plant is root rot.
A fungus that takes hold during cool, damp soil conditions causes root rot. In houseplants, such as the rubber tree, root rot tends to result from watering the plant too often or from improper drainage. Potting mixture that does not drain well or pots that do not allow water to drain invite root rot.
Root rot prevents the roots from absorbing water, so affected plants appear like they're not receiving enough water. This causes some homeowners to overwater further and worsen the problem. Above ground, leaves may turn yellow, become brown at the edges or drop off entirely. The plant fails to properly grow and begins wilting. Remove the plant from the pot if you suspect root rot, suggests the Purdue University Cooperative Extension Service. If roots appear slimy, black and decayed, root rot is the likely culprit.
Root rot is difficult to treat once it takes hold in severe cases. Fungicide drenches can eliminate root rot, according to the University of Kentucky Cooperative Extension Service. However, you must have an accurate diagnosis of the pathogen in order to select an approved fungicide and use only treatments approved for use on rubber plants. Contact your local extension office or nursery for more information on diagnostic services. If root rot has not progressed, re-establishing good cultural conditions may be enough for the rubber plant to fend off the problem.
The key to preventing root rot is proper watering and good drainage. Although rubber plants like moisture, conditions shouldn't be so wet as to encourage fungal growth. Check the soil before watering, according to Clemson University. If it is dry to the touch, water it. If it's still wet, wait until it begins to feel slightly dry. Clemson further recommends using a well-drained houseplant potting mixture so that water doesn't sit around the roots. Always empty the water from the tray under the pot when you're finished watering.
If you lose your rubber plant to root rot, you can start again with a cutting taken from a stem of the plant, according to the University of Missouri. Find the healthiest stem you can and take a 4- to 6-inch cutting just below where a leaf is attached. Remove the leaves from lower half of the plant, plant it in a light potting medium and add a rooting compound, available from nurseries or garden supply catalogs.