This native of southern and southeast Asia is neither made of
rubber nor used for it now, although a low grade of rubber was
made from the sap in the early 1900’s. Most of the world’s
rubber, instead, now comes from another rubber tree (Hevea
brasiliensis). The genus name (Ficus) refers to the
edible fig to which it is related, and the species name (elastica)
to the white sticky sap. This sap may irritate the skin or
stomach if eaten, so keep it away from pets and children that may
Although growing 50 to 100 feet tall in its native tropics, with
aerial roots that form trunks supporting the heavy limbs to the
ground, indoors rubber plants generally grow from two to 10 feet
tall. It has attractive, glossy and leathery leaves up to one
foot long and to five inches wide. They are oval to oblong.
Flowers and fruits are seldom seen on plants grown indoors.
While you may see it growing outdoors in full sun in southern
Florida as a landscape plant, indoors it prefers bright indirect
light and will tolerate low light. An ideal location is by a
window that gets morning sun from the east.
Water regularly while it is growing—generally spring and
summer—but don’t overwater. Let the soil dry to the touch before
watering. If in doubt, don’t water. Under-watering is better
than over-watering. Reduce watering when plants aren’t
growing—generally fall through winter. Make sure plants are in
pots with drainage holes, and that pots don’t sit in saucers
filled with water. Fertilize when plants are growing, according
to the label directions on product of your choice.
Rubber plants prefer humid air, but will tolerate the drier air
of most indoor environments. Also, they prefer warm temperatures—
60 to 65 degrees (F) at night and 75 to 80 degrees during day is
ideal. Yet they grow well at most temperatures above 55 degrees.
Avoid a colder temperature than this, sudden temperature drops, or
cold drafts such as near outdoor doorways.
Plants may grow tall and lanky indoors, particularly if grown
with lower light levels. You can either support them with a
stake, or prune them back in spring as growth resumes to make them
bushier. This is the time to repot them, too, if needed. If you
cut them back, you can propagate new plants from stem or tip
cuttings, or by air layering.
Air layering is the process of stimulating new roots to grow on a
stem while it is still attached, and is used on plants with thick
stems or canes such as rubber plants. Notch the stem where you’d
like roots to form, dust with a rooting hormone powder (available
at full service garden stores, or online), then wrap this area
with a moist foam or sphagnum moss. Cover with plastic (held with
twist ties) to maintain the moisture. Hopefully, after a few
months, you’ll find roots growing and you can cut the stem below
these, and pot. Use a houseplant soil (not garden soil) for
potting, or repotting.
The main pest you may find on rubber plants indoors are white
mealybugs. Wiping leaves periodically with mildly soapy water
will keep these from multiplying, and will clean dust off that
tends to accumulate on the large leaves. If leaves turn yellow
and drop off, that is a sign the soil may be staying too wet.
Leaves may just fall off, too, if plants receive too little light,
cold drafts, or are in air that is too dry. Using a humidifier
near plants will help them, as well as you, if indoor humidity is
While the species has dark green leaves, there are several
popular cultivars (cultivated varieties) that you often find
instead, some of which have been around since the Victorian era.
‘Decora’ has creamy white midribs contrasting on the dark green
leaves. ‘Doescheri’ has variegated leaves that are cream and
gray, with pink midribs. ‘Robusta’ has very large leaves up to 18
inches long, and tolerates low light well. ‘Rubra’ is perhaps the
most commonly found cultivar, its young reddish leaves maturing to
deep green with red edges. ‘Tricolor’ is just that, its green
leaves with cream and pink patches.
Rubber plants, themselves, may help you indoors as they’ve been
found to be one of the top “clean air” plants. In a famous study
by Bill Wolverton during the 1980’s while he was with NASA, this
plant was found to remove some chemical toxins from indoor air,
particularly formaldehyde. The latter can come from paper
products, particle board, plywood paneling, and synthetic fabrics.
His recommendation was to have at least two large (8- to 10-inch
pots) for 100 square feet of space.
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