The Council Tree (Ficus altissima) is a large ornamental tree belonging to the Moraceae family, known for its grandeur and popularity as an indoor plant. It is native to Southeast Asia, encompassing countries like southern China, India, Bhutan, Nepal, Myanmar, Thailand, Vietnam, Malaysia, Indonesia, and the Philippines. This species thrives in low-altitude and mountainous forests, occurring at elevations ranging from 328 feet (100 meters) to about 6,561 feet (2,000 meters). Commonly found in moist tropical forests, the tree can start its life cycle as an epiphyte, establishing itself on the branches of other trees, or as a lithophyte, growing in rock crevices or artificial structures.
The botanical name Ficus altissima is derived from Latin: “ficus” meaning fig tree, and the specific epithet “altissima” being the superlative of “altus”, meaning “very high” or “the highest”. True to its name, one of the primary features of the species is its ability to reach great heights in its natural habitat. It is commonly known as “Council Tree” or “Lofty Fig” in English, and “高山榕” (gao shan rong) in Chinese, which translates as “high mountain fig”.
Ficus altissima is a large perennial tree that can grow up to 98.4 feet (30 meters) tall. Its trunk is robust, often featuring tabular (buttress) roots at the base, which provide additional support. The bark is smooth and gray in color, with small light-brown pustules.
The branches are broad, and the young branches are pilose and often green. The leaves are alternate, elliptical to ovate in shape, with entire margins, measuring up to 3.9 inches (10 cm) long and 1.6 inches (4 cm) wide. They have short petioles and stipules that cover developing shoots.
The inflorescence of Ficus altissima is a syconium, a hollow, fleshy structure that houses unisexual flowers inside. This species is a functionally monoecious, meaning it presents both male and female flowers on the same individual. The flowers are tiny and not visible externally, as they are contained within the syconium. Pollination is carried out by specific wasps that enter the syconium through a small opening called the ostiole. After pollination, the syconia develop into reddish-orange fruits, measuring around 1 inch (2.5 cm) in diameter, which contain numerous seeds.
The most popular and widely cultivated cultivar of the Council Tree is ‘Yellow Gem’, also known as ‘Golden Gem’ or simply ‘Variegata’. This variety stands out for its oval leaves that are light green in color with yellowish or golden borders, forming highly decorative variegated patterns. The leaves have a leathery texture, maintaining a firm structure even in indoor environments with low relative light. This cultivar also shows more compact growth, making it even more suitable for pot cultivation and indoor environments.
The Ficus altissima is part of the strangler fig group, meaning that after feeding on the fruits, birds end up carrying seeds of the plant to the branches of other trees, where it germinates and exhibits initial growth as an epiphyte. This ecological strategy allows the seedling to colonize branches of host trees before developing descending roots that reach the ground. Once it touches the soil, the fig tree gains vigor and gradually thickens its stem and roots, strangling the host tree.
The process culminates in the formation of an imposing root structure, which in time can completely envelop the trunk of the support tree, eventually leading to its death by suffocation. This strategy gives the Ficus altissima a significant competitive advantage in dense tropical forests, where the competition for sunlight is intense.
Council Trees have a curious mutualistic relationship with wasps from the Agaonidae family, responsible for the pollination of the syconia. This highly specialized symbiosis ensures not only the reproduction of the tree but also the perpetuation of the wasp species, which use the syconia as shelter and a laying site.
In landscaping, Ficus altissima is used as a shade tree in parks, plazas, and large tropical and subtropical gardens, particularly because of its wide and dense canopy, comprised of horizontal branches that expand in an umbrella shape.
Due to its considerable size, the Council Tree is only suitable for large areas, such as farms and big gardens, and is unsuitable for narrow sidewalks, avenues, or confined spaces. Its vigorous growth requires regular management, especially of the aerial parts, to avoid conflicts with wiring and buildings. The superficial roots tend to thicken over time and reach large dimensions, damaging pavements and buried pipelines.
The species is also appreciated as a focal point in large-scale landscape projects, where its striking silhouette and majestic stature evoke a sense of monumentality. In botanical gardens, Ficus altissima is often planted as a demonstrative specimen to illustrate the epiphytic behavior and the mutualism between plants and insects.
In interior design, the ‘Yellow Gem’ cultivar is highly valued for its ornamental foliage and its resilience in environments with indirect light. As it has a smaller stature and slower growth compared to the original species, it adapts well to pots, frequently being used in living rooms, offices, entry halls, and commercial spaces such as shopping malls and shops.
Its aesthetic effect is enhanced by the vibrant coloration of the leaves, which contrasts with neutral walls and complements contemporary and modern interiors. Additionally, the Council Tree has the ability to remove volatile pollutants from the air, such as formaldehyde and toluene, contributing to the purification of the environment and the improvement of indoor air quality. This characteristic, well-documented in studies on phytoremediation, extends the functional value of the plant beyond its ornamental aspect.
The Council Tree (Ficus altissima), being a species native to the humid tropical forests of Southeast Asia, has specific requirements to develop healthily, both indoors and in external landscaping.
In outdoor areas, the Council Tree prefers exposure to full sun or partial shade, performing better in locations that receive direct sunlight for at least a few hours a day. Indoors, it adapts well to brightly lit areas, provided it receives intense indirect light, such as near a sunny window or under a skylight, being sensitive to excessive shading, which can cause chlorosis, leaf drop, and etiolation.
Ficus altissima favors a tropical to subtropical humid climate, with average temperatures between 64°F (18°C) and 86°F (30°C). While it can tolerate moderate temperature variations, it does not withstand frost or temperatures below 41°F (5°C) for extended periods. The relative humidity should be maintained between 60% and 90%, replicating the natural conditions of rainforests. In dry environments or with air conditioning, the use of humidifiers or trays with water under the pots is recommended, however, avoiding root waterlogging.
The plant requires a fertile, deep, well-drained soil rich in organic matter. For garden cultivation, the planting bed soil should be enriched with organic compost, worm castings, or well-rotted manure. The ideal texture is loamy-sandy, with good moisture retention but without causing flooding.
For pots, the potting mix should contain a balanced mixture of garden soil, perlite or coarse sand, and organic matter, such as coconut fiber or peat. Drainage is essential to prevent root rot, with layers of gravel or expanded clay at the bottom of the container.
Planting should preferably occur in the spring or early summer, when temperatures are more conducive to rooting. After planting, watering should be frequent, keeping the potting mix moist but never waterlogged, at least for the first two years. After the young plant is established, which will show signs of robust growth, watering should be gradually spaced out.
In pots, it is recommended to water when the first few inches of the potting mix are dry to the touch. Fertilization should be regular, with balanced fertilizers (e.g., NPK 10-10-10 or 20-20-20), applied monthly during spring and summer. Nitrogen-rich supplements promote leaf development, while organic fertilizers such as bokashi or organic compost contribute to the overall health of the plant.
Pruning is recommended for growth control and maintenance of aesthetic shape, especially in indoor environments. Damaged, diseased, or excessively long branches can be removed using sterilized tools, preferably at the end of winter or beginning of spring. Maintenance includes periodic removal of dried leaves, pest inspection, cleaning leaves with a damp cloth, and replanting the potting mix every two years.
Replanting should be carried out when the roots begin to emerge through the drainage hole of the pot. Delaying this procedure causes root entanglement and substrate exhaustion, leading to general weakening of the plant. In this case, it is advisable to prune the roots, followed by a proportional pruning of the aerial part of the plant.
Ficus altissima demonstrates good tolerance to moderate winds and proximity to the sea, making it suitable for cultivation in protected coastal regions. However, it has low tolerance to frost, intense cold, and prolonged drought. Irrigation should be intensified during dry periods, especially for newly established specimens. Resistance to herbivory is moderate, being occasionally attacked by caterpillars, especially in open tropical environments.
The species is susceptible to scale insects, mites, aphids, and whiteflies, particularly in conditions of low humidity and inadequate ventilation. These sucking insects compromise photosynthesis by feeding on the sap and cause spots, deformations, and premature leaf drop. The presence of sooty mold, caused by fungi that develop on the sugary excretion of scale insects, is an indirect sign of infestation.
Control can be achieved through meticulous cleaning, insecticidal soap, neem oil, or specific applications of biological insecticides. In terms of diseases, excessive moisture can promote the development of root rot by fungi of the genus Phytophthora or Pythium, requiring adjustment of watering practices, and in severe cases, replanting of the plant.
Propagation of the Council Tree primarily occurs through semi-hardwood stem cuttings, preferably during spring or summer. Branches should be 4 to 6 inches (10 to 15 cm) long, contain at least two leaves, and be placed in a light and moist potting mix, under partial shade and high humidity. Rooting can be stimulated with the use of indolebutyric acid-based rooting hormone.
Air-layering is also highly efficient for propagation and can also be used to reduce the height of plants that are too large for indoor environments. Moreover, never plant a Council Tree that has overgrown in a small garden or on the sidewalk. It is not suitable for such small spaces and will cause significant damage in the future.
Another possible form of propagation, although less common in home cultivation, is by seeds, which require a sterilized substrate, consistent moisture, and a protected environment for germination. Germination is inconsistent and can take anywhere from two to six weeks, depending on environmental conditions and the viability of the seeds. In seed propagation, it is likely that the offspring plants will not maintain the variegation, if they are from a variegated cultivar such as ‘Yellow Gem’.
