Rubber plant: expert tips on cultivation, care & propagation
The rubber plant is very popular as a houseplant. Here you will learn everything you need to know about the care, pruning and propagation of the rubber tree plant.
This tree, with its impressively large leaves, is a popular addition to any room or office, but there is certainly a lot more to know about the rubber plant (Ficus elastica). For example, did you know that the ficus actually belongs to the same family as figs and that you can actually get rubber for gum from its sap? We have compiled more interesting facts about the popular rubber tree for you here. You will learn everything about the origin, different varieties, how to buy, location, care and typical disease patterns of the rubber plant.
- Rubber plant: characteristics and origin
- When does the rubber tree bloom?
- Rubber plant varieties
- Buying a rubber tree
- Growing rubber plants: the perfect location
- Repotting your rubber plant
- Rubber plant propagation
- Rubber plant care
- Rubber tree losing leaves
- Common diseases and pests
- Is the rubber plant poisonous?
Like edible figs (Ficus carica), the rubber tree belongs to the genus ficus, that is, to the fig family, and thus to the mulberry family (Moraceae). It is classified as part of the subgroup of banyan figs, which also includes the poplar fig (banyan tree), significant in Buddhism. According to Buddhist tradition, Siddhartha Gautama experienced “enlightenment” while sitting under a poplar fig tree and thus became Buddha.
Another name for the rubber tree is Indian rubber bush. Both names already indicate the use of the plant’s sap, because it contains rubber, from which gum can be made. However, this is quite a time-consuming process: It takes a full seven years before rubber can be harvested for the first time after planting. The rubber tree can live up to 100 years under ideal conditions and during this time rubber can be extracted from it up to 30 times. However, the rubber tree is hardly ever used for rubber production today. Generally, only the Para rubber tree (Hevea brasiliensis) is used for this purpose.
Here, the tree has much more of an aesthetic function and is used as an ornamental plant. While the rubber plant was so popular in the 1980s that it seemed like everyone had it in their homes, the hype surrounding the tropical tree quickly died down afterwards and it disappeared from many rooms and offices once again. Today, however, the tree is experiencing a revival and is once again making its way into our homes. The main reasons for its popularity are obvious: the rubber tree is beautiful to look at, robust and easy to care for. In addition, it has been proven that the tree can filter formaldehyde from the air and thus contribute to higher air quality in the room.
Even Frank Sinatra was so excited about the rubber plant in 1961 that he even wrote a song about it called “High Hopes.” One last piece of information worth knowing about the special ficus: In parts of India, people direct the roots of the tree across gorges and rivers. This creates very impressive, so-called living bridges.
Rubber plant: characteristics and origin
The rubber plant’s native home is an area stretching from northeast India (Assam) to Indonesia (particularly the islands of Sumatra and Java). Today, however, the Ficus elastica is grown worldwide. In tropical climates without frost it thrives splendidly outdoors, in colder climes it is generally grown as a houseplant.
In the wild under tropical conditions, the tree can grow up to 40 metres high. In the process, its trunk reaches a thickness of up to two metres in diameter. The Ficus elastica is a tree-choking hemiepiphyte (strangler fig). Its bark is light brown to medium brown in colour and is smooth. The trunk may also develop aerial roots in the wild to anchor itself more firmly in the ground or to support heavy branches. However, this does not occur in a pot. Young rubber tree plants can even grow as epiphytes, or perching plants, without contact with the soil.
As a houseplant, a rubber plant can grow up to two metres tall, if you let it. The leaves of the tree are up to 30 centimetres long, thick and leathery. They grow alternating broad oval and pointy leaves. The petioles can be between two to five centimetres long. The leaves are shiny and dark green on the upper side, the underside is light green.
Keeping rubber trees as houseplants can be complicated when it comes to flowering and fruit. The tree almost never forms flowers in a pot. They are only pollinated by a very specific species of wasps – and this is the only way they will ever bear fruit.
When does the rubber tree bloom?
Yes, rubber plants are able to produce flowers and subsequently small fruits. But popular houseplant species such as rubber trees and their cousins, the vine figs (Ficus benjamina), rarely bloom and, accordingly, rarely bear fruit. Actual rubber plant flowers are small, greenish and inconspicuous. They are very unlikely to occur in a plant growing indoors in a pot. Even in rubber plants that grow outdoors in warm, temperate to semi-tropical conditions, flowering is rare.
As with other members of the ficus genus, the flowers require a particular species of fig wasp to pollinate them in a jointly developed symbiosis. Due to this relationship, the rubber plant does not produce very colourful or fragrant flowers to attract other pollinators. Ficus elastica forms small, yellowish figs as fruit, but they have nothing to do with the delicious figs we know from the Mediterranean region, they are also inedible.
Rubber plant varieties
A rubber tree does not necessarily always have fully green leaves. There are also varieties that are characterised by variegated leaf colouration. Belowe we have compiled, the most beautiful varieties:
- ˈRobustaˈ: Probably the most popular variety of rubber plant; as the name implies, this variety is extremely robust; the leaves are oval and dark green.
- ˈAustralisˈ: This rubber tree variety is perfect for those with little space available, due to its stocky stature.
- ˈBelizeˈ: Probably the most colourful variety; the leaves are variegated red, white and green.
- ˈTricolorˈ: This variety also brings colour to any room; the leaves are dark green with white and pink spots.
- ˈVariegataˈ: This variety bears green leaves with yellow areas and yellow leaf edges.
- ˈDoescheriˈ: This variety is also tricolor; its leaves are green with cream and grey patterns.
- ˈMelanyˈ: Particularly dense and bushy growth; the leaves are dark green with a slight red tinge.
Buying a rubber tree
In order to be able to enjoy your new green roommate for a long time, you should take special care when buying. Pay attention to the following points when buying a rubber plant:
- Vital and healthy appearance
- Plant is not losing leaves
- No stains or discolouration on the leaves
- No foul odour
- The plant is free of disease and pests
You can buy rubber trees in hardware stores, garden centres, many homeware stores or on the Internet. It is worth doing some research and comparing prices before buying, as price differences between individual dealers can be significant. The size of the tree is, of course, a deciding factor in the price. The tree grows quite slowly, which is why it can take a few years for a small tree to grow into a stately plant.
Growing rubber plants: the perfect location
For your tree to grow and thrive, it should be placed in a suitable location. The rubber plant likes warmth and sunlight – no wonder, since it originates from warm, tropical regions. However, you should still avoid strong, midday sun, as this can be harmful to the tree. It is also important to shield the Ficus from drafts. It likes a warm climate, similar to that of its tropical home. It prefers temperatures between 18 and 20 °C. If the temperature drops below 16 °C, it starts to shiver. Light is also important to the rubber tree, because it prefers it as bright as possible. If it is too shaded or dark, the tree may start to shed its leaves. So always choose the brightest possible place for your tree.
Tip: Varieties with multicoloured leaves need even more light than monochrome green varieties. It is therefore necessary to use a plant lamp in darker areas, so that the tree will not lose its leaves.
Another aspect is the humidity of the air. Indoor air that is too dry is bad for the rubber plant. It is best to ensure that the humidity is always above 50%.
Environmental requirements for the rubber plant:
- Sunny to partial shade
- No strong midday sun
- No draughts
- Warm, between 18 and 20 °C
- As bright as possible
- Ideal humidity above 50%
Repotting your rubber plant
As soon as the surface of the substrate in the pot of the rubber plant begins to arch upward or sinks below the roots, it is time to repot the Ficus. This should be done at least every two to three years. If the rubber tree has too little space in the pot, it may start to shed its leaves. The best time to repot is in spring from the end of February to the beginning of March.
First, mix suitable substrate for the rubber plant. It is important that the substrate is as rich as possible with good permeability. Otherwise, the pot can become waterlogged, which will harm the tree. With too high a nutrient content in the substrate, you are not doing your rubber tree any favours either; it had better be low in nutrients. As a suitable substrate, you can mix conventional potting soil with perlite, lava granules or coconut fibres to give structure to the soil, making it more permeable.
The ideal potting mix for your rubber tree:
- Rich in structure
- Moderate nutrient content
- Potting soil enriched with perlite, lava granules or coconut fibres
The new pot for your Ficus should be only be slightly larger than the old one. This is the best way for the tree to develop. Preferably, choose a planter that is only five to ten centimetres larger in diameter than the last. Then create a drainage layer in the pot, so that the water can drain away well. Clay shards or expanded clay, for example, are suitable for this purpose. Now fill mixed substrate over the drainage layer to a third of the way up and place the rubber tree in the middle of the pot.
Tip: With larger specimens, it is almost impossible to repot alone. Therefore, seek help with this endeavour.
Now fill the rest of the pot with substrate, leaving about five centimetres below the rim. Finally, water the plant well, but remove excess water from the drainage dish.
Repotting rubber plants:
- Carefully pull the root ball from the old pot
- Remove old, dead a clean, sharp knife
- New planter: Maximum 5 – 10 cm larger than the old one
- Create a drainage layer
- Fill one third of the planter with substrate
- Put the tree in the middle of the pot
- Fill the planter with substrate
- Leave approx. 5 cm space from the rim
- Water well
Rubber plant propagation
If you cannot get enough of rubber plants, consider propagating your tree. Fortunately, the Ficus elastica can be easily replicated via two different methods: Either via cuttings or by air layering. In cutting propagation, cuttings are taken from a healthy shoot on the tree and grown in cutting substrate. This method is simple to perform. Air layering, on the other hand, is a little more complicated: Here a shoot is cut and divided by a wedge. The cut is then wrapped with moss, which should stimulate the shoot to form new roots. This procedure is more time-consuming than taking cuttings. But if it is successful, you’ll have already gained a very large new rubber tree.
Step-by-step instructions on the propagation methods of the rubber tree can be found here.
Rubber plant care
Fortunately, the rubber tree is considered hardy and therefore requires little care. However, you should still give your tree a little attention. It will reward you with vigorous growth and beautiful leaves. Therefore, we’ll tell you everything you need to know about proper watering, pruning and fertilising of this popular houseplant.
You can read detailed care instructions for the rubber tree in our special article on the subject here.
Watering too generously is a common care mistake with the rubber plant. The tree is much more forgiving of a brief period of drought than having soggy feet. Therefore, when watering the tree, you should proceed as follows.
Watering rubber trees:
- Check substrate with finger test
- Allow top substrate layer to dry off
- Water in moderation
- Waterlogging should be avoided at all costs
- Alternatively, water by immersion
Pruning rubber trees
The rubber tree is considered pruning tolerant, but generally does not require regular pruning. Pruning is only necessary when you want to contain the growth of the tree, encourage side shoots, or when the tree is looking unsightly. Of course, you should also reach for the shears if the tree is infested with pests. For pruning, it is recommended to always use clean tools, such as a sharp knife or secateurs. The milky-white plant sap that oozes from the cuts can because skin irritation and is poisonous. Therefore, always wear gloves when pruning. You can dab the cuts with a damp cloth or sprinkle them with lukewarm water.
Pruning your rubber plant:
- To contain growth, by one third
- To promote side shoots, cut above nodes on the trunk
- Cut off side shoots for upward growth
- Immediately remove any parts of the plant that are dried up, dead or affected by disease or infested with pests
- Treating wounds
For even more tips and tricks on how to best prune your rubber tree, read on.
The rubber plant also does not like too many nutrients. Therefore, less is more when it comes to fertilising.
Fertilising your rubber plant:
- Do not over-fertilise
- It is best to fertilise every 3 months using a fertiliser with organic long-term effects
- Alternatively, use a liquid fertiliser every 6 weeks
Our Plantura All Purpose Plant Food with long-term effects is perfect for rubber plants. It provides your tree with all the essential nutrients in the best possible way and is also good for the environment, as it consists only of natural ingredients.
- Perfect for a variety of plants in the garden & on the balcony
- Promotes healthy plant growth & an active soil life
- Long-lasting fertiliser that is free from animal products - child & pet friendly
Rubber tree losing leaves
Of course, if your rubber plant is losing its leaves, it will not be as nice to look at and you should act as soon as possible. A loss of leaves can have different reasons. For example, incorrect watering, the wrong location or lack of space in the pot, incorrect feeding or even pests can be the because. That is why the first thing to do is to find out the because. Once this is known, you can act accordingly. The following measures will help your rubber plant against leaf loss.
Measures against rubber tree leaf loss:
- Changes of location
- For lack of space, repot in a larger container
- For overly dry substrate, immerse the whole pot in water
- For waterlogging, repot
- For overfeeding, repot
- For pest infestations, use a suitable treatment or introduce beneficial insects
Common diseases and pests
If your rubber plant is weak or its conditions are not optimal, the likelihood that your tree will be attacked by pests or diseases will increase. As a preventive measure you should therefore always pay attention to optimal conditions for growth. The most common reasons for pest infestation is too warm a location and low air humidity.
The most common pests of rubber plants are spider mites (Tetranychidae), scale insects (Coccoidea), and woolly aphids (Homoptera). You can recognise an infestation by the fact that the leaves turn yellow, dry up and fall off. Less commonly, the rubber tree is also attacked by fungus gnats (Sciaridae). Possible means that you can use against the unwanted pests are ecological or even chemical sprays. Neem oil, for example, is proven against pests. Another way to get rid of unwanted pests is beneficial insects. These are natural enemies of the pests, which love to eat them and fight them in this way. For example, predatory mites (Phytoseiulus persimilis) help as antagonists against spider mites. Ichneumon wasps (Ichneumonidae) are suitable beneficial insects against scale insects and woolly aphids. For fungus gnats, the use of nematodes (Steinernema feltiae) may help.
Is the rubber plant poisonous?
As beautiful as the tree is to look at, you should definitely not ingest it. This is due to the fact that parts of the tree contain chlorogenic acid in addition to rubber. This is slightly toxic and thus the rubber plant is also classified as slightly toxic. Contact with the skin may because skin irritation or even allergic reactions. If part of the tree is swallowed, it irritates the mucous membranes; other symptoms include nausea, vomiting, and stomach cramps. In adults, poisoning is usually not very serious, but it is much different in young children. In the event of a suspected rubber tree poisoning, you should definitely consult a doctor.