How to Grow a Rubber Plant Tree
If you are lucky enough to obtain some seeds from the ficus elastica plant, you may wish to try to grow a rubber tree from them.
Most people don't even know a rubber plant produces flowers, never mind seed. Ficus elastica is part of the family Moracaea, which include figs and mulberries.
Like most people, I have grown rubber plants as houseplants all my life, and now that I am living in a Mediterranean climate, I have one growing in the garden.
It has never flowered. In fact, I have never seen a flower on a rubber plant.
I've planted some of the seeds. Although they are quite large, I read that it is recommended they are planted on the surface of the soil, and kept in a warm place out of the sunshine until they germinate. I have placed mine inside a cut down plastic bottle with drainage holes on the bottom (to create a mini-greenhouse) outside in a sheltered part of the terrace.
This winter has been particularly cold. Whether they have survived remains to be seen.
The fig wasp pollinates rubber plant flowers
Ficus elastica flowers need a special kind of wasp, an agaonid wasp known as the fig wasp to pollinate them. This wasp is not present everywhere, so if your indoor rubber plant produces flowers, it may have trouble getting pollinated to produce fruit.
The fruit is fig-like, small and green. The flowers have been described as insignificant as the plant does not need to attract pollinators.
It seems a bit of a strange set up to me, as the fig wasps lays its eggs in the flower which in turn means that they hatch inside the fig, yet seemingly this is the only way this plant can reproduce seed. It is a two-way interdependence, as the fig wasp associated with the ficus elastica, cannot lay its eggs elsewhere.
Each to their own, I suppose!
The Rubber Plant
This is a stunning exotic looking houseplant, with its wide glossy eliptical leaves that can grow as large as 14" x 7", especially on younger plants.
It is non-deciduous and so does not lose its leaves in the winter. New leaves are covered with a red capsule which falls off as they unravel.
In USDA zones 9b to 11 they can be grown outside, where they form trees up to 100' high with wide-spreading branches and aerial roots dropping from the main stem and branches. They have buttress roots, which are stabilising roots that many trees have developed when living in poor and rocky soil where they can't penetrate the ground deeply. These roots snake out from the tree in all directions and intertwine with the roots of neighbouring trees to form a stable network for the whole forest.
Like typical rainforest jungle trees, they can tolerate sun or shade, and are not bothered about acidity/alkilinty of the soil or type of soil. They especially like living in tropical climates where it is warm and wet, but tolerate drought extremely well.
Indoors, they can grow as high as your ceiling, and can be safely cut back if they threaten to outgrow your house.
The sap is milky white and can be used to make rubber, although commercially the sap of the the para rubber tree is preferred, a different species.
Care should be taken when handling the sap, as it is an irritant and can be fatal if ingested.
They can be propagated by either cuttings or air-layering. The latter is where the stem is cut with a knife (while still attached to the parent), then wrapped in sphagnum moss and sealed inside polythene binding until new roots develop.
Cuttings can be taken and placed in a compost/vermiculite mix in a pot inside a plastic bag, well -watered then ignored until you see a new leaf forming.
It is well worth propagating your rubber plants and spreading them throughout the house, as they are on NASA's list of the air-purifying houseplants.