Rubber Plant (Ficus elastica) Evergreen Tree: Growing Methods, Precautions, Indoor Toxicity, and Whether It Is Suitable for Growing Indoors

The rubber plant is an evergreen tree of the Moraceae family. Other names: rubber tree, Brazilian rubber, Indian rubber tree, Indian banyan large-leaf green, red Burmese tree, red-mouth rubber tree. It is suitable for indoor decorative arrangements, often used to beautify living rooms and studies, and also suited for placement on both sides of the lobbies and in the center of the halls of large buildings, appearing majestic and spectacular. So how do you grow rubber plant? What are the growing methods and precautions?

Rubber plant, also known as rubber tree and Brazilian rubber, is an evergreen tree of the genus Ficus in the Moraceae family. Its leaves are thick and broad, deep green in color, with bright red terminal buds; when the stipules split open they hang down just like red tassels, quite charming. The rubber plant has an obvious trunk with few branches and aerial roots. Leaves are simple and alternate, oblong, thickly leathery, glossy green, with many parallel lateral veins; young leaves are red, and the petioles are sturdy. The rubber plant has high ornamental value and is a well-known potted foliage plant.

Growing methods for the rubber plant:

Best propagation time: The rubber plant is best propagated in spring and summer.

Best growing soil: To grow the rubber plant, use loose, well-draining leaf mold. The usual ratio is garden soil : humus soil : sand at 2:2:1. It is best to place moss the same size as the pot on top of the bonsai; this is both attractive and plays a good role in drainage and aeration.

Humidity requirements: Feel the condition of the potting soil with your hand and follow the principle of “dry then wet.” Do not water frequently; when you water, water thoroughly. Overwatering will cause root rot and leaf drop. In midsummer and during dry periods, you can spray water on the leaves to keep them moist. In autumn and winter, watering should be reduced.

Best growing temperature: The most suitable temperature for the rubber plant is 20-25°C. It tolerates high temperatures and can still grow well when the temperature is above 30°C. The rubber plant is not cold-tolerant, and the safe overwintering temperature is 5°C. Variegated varieties are slightly less cold-tolerant, and the overwintering temperature is best kept above 8°C; when the temperature is low, they will produce a large number of fallen leaves.

Best growing light: The rubber plant likes bright indirect light and has a certain tolerance for shade. It is not tolerant of strong direct sunlight; when the light is too strong, the leaves will be scorched, turning yellow and burnt. It should also not be kept in too dark a place, otherwise it will cause a large number of fallen leaves and cause the beautiful markings of variegated varieties to fade. From May to September, shading should be provided, or the plant should be placed in a spot with plenty of indirect light. At other times, it should be given ample sunlight.

Precautions for growing the rubber plant:

Fertilizing: The rubber plant grows quickly, so nutrients should be supplied in time to keep the plant growing vigorously. Apply a nitrogen-based fertilizer 2-3 times a month. Variegated varieties grow relatively slowly, so the frequency of fertilizing can be reduced while increasing the application of phosphorus and potassium fertilizer to make the markings on the leaves bright and colorful. If too much nitrogen fertilizer is applied or only nitrogen fertilizer is used, the color of the markings will fade or even disappear. In September, nitrogen fertilizer should be stopped, and only phosphorus and potassium fertilizer should be applied to improve the plant's cold resistance. In winter, the plant goes dormant, so fertilizing should be stopped.

Watering essentials: The rubber plant likes a moist soil environment, and during the growing period water should be supplied fully to keep the potting soil moist. In winter, watering needs to be controlled; when the temperature is low and the potting soil is too wet, it easily leads to root rot.

Propagation points: The rubber plant is commonly propagated by cuttings. Spring and summer are best. Choose a one-year-old branch from the upper part of the plant, 20 cm long; after cutting, it roots in 30 days and can be potted in 50 days. If summer cuttings are watered improperly, the cuttings easily rot. When taking cuttings, cut a semi-lignified one-year-old branch, remove the tender young part at the tip, and choose the middle section as the cutting, which has the highest survival rate. The cuttings should be 2-3 nodes long, retain 1 upper leaf, and cut that leaf in half, or use string to roll the retained leaf upward and tie it, to facilitate cutting and reduce water transpiration. When cutting, first seal the upper and lower cut ends of the cuttings with clay to prevent too much sap from flowing out and affecting survival, then insert the cuttings into plain sand; at a temperature above 20C, they will root about 40-50 days after cutting.

In addition to the above propagation by cuttings, single-bud cuttings, air layering, or water propagation can also be used.

Pruning points: When the rubber plant grows to 1 m tall, it needs to be topped to promote branching and maintain a beautiful tree shape. When pruning in spring, remove the forked branches, inward-growing branches, dead branches, and thin weak branches inside the crown, and shorten the runaway branches sticking out beyond the crown, so that the inside of the plant has good ventilation and light and the tree shape remains round and neat. If the crown is too large, the outer branches can be shortened overall. During the growing period, dense branches should be thinned at any time and long branches shortened.

Repotting: After rubber plant seedlings are potted, they must be repotted every spring; mature plants can be repotted once every 2-3 years to add fertile soil.

Pest and disease control: The rubber plant is prone to anthracnose, whose pathogen is Gloeosporium elasticae. This disease mainly occurs in the high-temperature summer season, and the main affected part is the leaves. Its symptoms are round or oval gray spots appearing on both sides of the leaf veins; in severe cases, the spots merge into one and spread to the whole leaf.

Control method: Combined with pruning, remove diseased branches, diseased leaves, and dead tips to reduce the pathogen. In the early stage of the disease, spray 50 percent carbendazim at 1000 times or 70 percent thiophanate-methyl at 1200 times solution.

Is the rubber plant toxic? Is it suitable for growing indoors?

Growing a rubber plant at home can be said to have more advantages than disadvantages. The toxicity of the rubber plant is mainly in its sap. Under normal circumstances, poisoning will not occur if the rubber plant is not eaten, and the plant does not release toxic gases. It also beautifies the environment and can absorb harmful gases in the air such as CO, CO2, and hydrogen fluoride, effectively purifying the air.

Especially in newly renovated houses, growing a rubber plant can effectively absorb volatile formaldehyde, such as from newly bought furniture. Growing a rubber plant in a place without ventilation can effectively improve air quality, because the rubber plant can regulate air humidity and oxygen content; because its leaves are relatively broad, it can carry out vigorous photosynthesis in a place with ample sunlight.

The rubber plant has strong plasticity, and proper pruning can create a plant with very high ornamental value. So, how should the rubber plant be pruned to look better?