Rubber Tree Plants

Susan Patterson
Rubber Tree

Rubber tree plants are tough, showy, evergreen plants from the tropical forests of Asia. It is known by the name Ficus elastica, or India rubber plant. But it's not in any way related to the true rubber tree Hevea brasiliensis - a relative of the Christmas plant poinsettia - cultivated for the production of natural rubber/latex. Nevertheless, this large-leaved decorative plant belonging to the fig and the banyan tree family is an even bigger tropical tree.

Identification

Rubber tree fruit
Rubber tree fruit

The thick, leathery, oval-shaped large leaves with interesting color or pattern are the main attraction of a rubber plant, but some have bright red or orange leaf sheaths too. They enclose unopened leaves in a tight roll and stand out like bright candles among the dark foliage.

Flowers and fruits are rarely seen in plants grown indoors, but some mature specimens may have oval fruits at the leaf nodes. As with all plants of the fig family, the flower and fruit are one and the same from the outside. It is actually a type of inflorescence (cluster of flowers) called hypanthodium that needs specific wasp species for pollination. Rubber plants are propagated either through tissue culture or layering.

Some rubber plants are sold as Ficus robusta, but it is only a hardier cultivar of F. elastica just like another compact cultivar sold as 'Decora' and a variegated variety as 'Doescheri'. It is better to go by the color and pattern of the plant than by its name alone. Many nurserymen use growth retardants to keep the plant compact and bushy. Light conditions can also change the pigmentation and habit of these plants.

Popular Varieties

  • F. elastica 'Doescheri' - Dark green, cream and muted green patches
  • F. elastica 'Tineke' - Green leaves with cream variegation and pink highlights referred to as strawberry-cream
ficus elastica burgundy
Ficus elastica 'Burgundy'
  • F. elastica 'Black Prince' - Very dark leaves with bronze undertones and red leaf sheath
  • F. elastica 'Ruby' - Green and cream leaves washed with bright red and red veins and leaf sheaths
  • F. elastica 'Burgundy' - Dark reddish green leaves as the name implies; it may be having dark-red leaf sheaths

Care and Maintenance

Rubber tree plants are not fussy, provided they get a brightly lit spot and some water. At the same time, you cannot say they thrive in neglect because regular care and occasional feeding can bring out shiny leaves and lush growth, the two best attributes of this plant.

Temperature

It doesn't matter what your USDA zone is if you intend to keep your F. elastica plant indoors. The ideal temperature range is 75-80 Farenheight (F). This native of the tropics is stressed when it is cooler than 60 F and when the temperature rises above 80 F without the moderating effect of humidity.

They grow extremely well outdoors in zones 10 and 11; so well that it can be dangerous to plant one close to your house or retaining wall. Its thick and prolific roots can be a menace. In fact, they are so strong, they can be braided and turned into living bridges across country streams. Pruning doesn't discourage root growth.

Many people in zones 8 and 9 also manage to grow F. elastica in their garden with limited success. The plant may lose leaves when temperatures fall, but hard pruning in late fall and some frost protection may keep them going.

Light

rubber trees in landscape
Landscape example

A sunny spot or partial shade is ideal for a rubber plant growing outdoors, but an indoor specimen needs only bright light. Rubber plants may tolerate low light conditions for a short period, but they are not as tolerant as the snake plant sansevieria or the pothos money plant. The variegated ones and those with colorful highlights will lose some of their bright pigmentation in low light and the burgundy one may become greener. Lanky growth with fewer leaves is another consequence of insufficient light.

At the same time, too much exposure can burn the leaves and change the color patterns. Solid green and burgundy are not as affected by excess light.

Water

Rubber plants are naturally resistant to drought as most plants with milky latex are. When grown as houseplants, they seem to appreciate regular watering, but it is the humid microclimate created by the damp soil that helps the plant more. It is better to allow the soil to dry out between watering to avoid root rot. You can kill a rubber plant more quickly by over watering than by under watering. Increase the humidity by misting the leaves or keeping a dishful of water by the pot.

Pruning

Rubber plants are usually propagated by layering, so the young plant you bring home may be having a single thick stem unless it is already made bushy pruning. Left to itself, each stem may grow several feet and start losing the lower leaves. You can prune your plant regularly to promote branching.

If the plant is single-stemmed, wait until it is two feet tall, and then prune it to half the height. Or you can let it grow six feet tall and then trim at five feet to make an interesting 'standard.'

Indoor rubber plants can be trimmed any time of the year, but late spring or early summer will help the plant rebound faster. Also, you will have a better chance at rooting a few of those cuttings to make more plants.

How to Propogate Rubber Tree Plants

If you already have a rubber plant, you can make several new ones by air layering, a nearly foolproof technique.

Steps

You will need some sphagnum moss, a plastic sheet, and string. Follow these easy steps:

  1. Make a slanting upward cut halfway through a stem and spread rooting powder on the cut.
  2. Insert dampened moss in the wedge, and cover the area with more damp moss, enveloping it with plastic sheet and securing it in place with string.
  3. Roots will develop in four to six weeks.
  4. Cut it off the mother plant and pot it up.

When you prune, try rooting the tip cuttings directly in a pot. Or get a few cuttings of a different variety from a friend. Just stick them in pots filled with a mixture of peat moss and perlite after dipping the cut ends in rooting hormone. Keep the mix damp and watch out for roots emerging from the drainage holes. Providing gentle bottom heat may speed things up a bit.

Potting

potted rubber plant
Potted rubber plant

Select a pot size that suits the height of your rooted cutting or purchased plant. Since they have a tendency to be top-heavy, large-sized pots are best. You can avoid frequent repotting too. A regular houseplant potting soil is good enough for the rubber plant as long as good drainage is ensured. Fill the pot half way with soil.

Remove the plant gently from its growing medium and ease out the tangled roots with the tip of a pencil. Place it in the pot and fill in more soil until it comes up to three-quarters of the height of the pot. Firm it up around the plant. Water thoroughly and allow excess water to drain off. Water again when the soil on the surface begins to dry.

Pests and Diseases

Rubber plants are not troubled by many pests or plant diseases, but scale insects can infest the leaves and young branches. Neem oil spray works well against them, but if the plant is big, it may not be practical. Since contact insecticides will not work, you may need a systemic insecticide such as imidacloprid.

Yellow and brown leaf spots may be caused by Cercospora fungus. A fungicidal spray can be used against it.

Both the above problems can be limited to some extent by removing the affected branches.

Toxicity

ASPCA has included Ficus elastica as a plant that may cause "moderate gastrointestinal tract irritation" to cats, but it is listed as non-toxic to humans by the California Poison Control System. But be on the safer side while pruning or breaking off leaves from you rubber plant as the latex may cause mild skin irritation and severe eye irritation on contact. Eating any plant parts may cause vomiting and mild gastric problems.

Fill Some Space

If you have some space that needs vertical interest, consider a rubber tree plant, whether indoors or out. You can find rubber tree plants at most garden centers or purchase through online retailers. Just be sure to give it lots of room to spread and be happy.

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Rubber Tree Plants