It is one of the most widely used in ornamental horticulture, ranking first in sales probably due to its adaptability and easy cultivation.
1. Taxonomy and Origin
The Ficus genus belongs to the family of Moraceae and comes from tropical and subtropical areas of Europe, Asia, Africa and the Pacific. Within this genus, there are numerous species of which about 830 are accepted.
It is one of the most widely used in ornamental horticulture, ranking first in sales probably due to its adaptability and easy cultivation. Furthermore, it has a great value for its decorative leaves and the overall shape of the plant that makes it suitable for both indoor and outdoor gardens.
Generally, it is characterized by the presence of latex conducting vessels and the development of a powerful root system.
Photo: Miran Rijavec
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It is difficult to establish common features of this genus as it is very diverse. Anyway it can be generalized that the leaves are simple with linear and sometimes lobed margins. On the other hand, it also gives flowers and if fertilization happens, it develops into a small fruit that contain seeds.
There are many commercialized species and thanks to the development of propagation techniques "in vitro”, the renewal of varieties is almost constant. A grouping of species and varieties can be:
1. Plants with very woody stem, large leaves and tree appearance. Species in this group are:
- F. elastica: it is the best known species. It has oval leaves, dark green, shiny and with clearer midrib at the upper part of the leaves and somewhat reddish on the underside. From the original type, new varieties have developed: 'Decora' and 'Robusta' green colour 'Rubra' purple colour, ‘Schryvereana "" Doescheri "and" Belgaplant "with variegated leaves, etc.
Ficus elastica. Photo: himoegypt
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- F. lyrata: broad leaves with lobed edges, dark green and marked with yellowish veins. It has regained interest with the propagation "in vitro".
- F. cyathistipula: oblong, leathery leaves with good branching and many fruits.
- F. benghalensis: commonly known by the name of 'Bengal fig'. It presents a very striking appearance because of the many ramifications.
- F. altissima and F. religiosa: they are garden species and are occasionally cultivated indoors.
2. Plants with more bushy appearance and medium or small leaves. In this group are:
- F. benjamina (F. nitida): is the most economically important species and has thin and inclined branches where pointed leaves develop, bright green in the original plant. Currently the range of varieties is very extensive and ‘Golden King', 'Golden Princess', 'Exotica', 'Starlight', 'Nana', etc are the most popular varieties.
- F. deltoidea: it has smaller and more rounded leaves
- F. stricta, F. buxifolia, F. retusa, F. leprieurii (F. triangularis), F. aspera (F. parcelli), F. rubiginosa and F. celebensis are also occasionally grown.
3. Climbing or hanging plants: F. pumila, climbing growth habit with small leaves that increase in size when they are exposed to direct sunlight and F. sagittata (F. radicans), with long variegated leaves in some forms.
Development: Most of the copies are sold when they are about 46 cm and have between 5 and 8 leaves. It can also be obtained more mature plants, 1m high. Some species can reach several meters indoors. F. elastica and F. benghalensis under favourable conditions, they can grow between 60 cm and 1 m per year; F. lyrata and variegated types, about 30 cm.
Longevity: it is a well-maintained plant and it can be very long-lived.
Flowering time: old plants only flower and their fruit is similar to a fig fruit.
3. EDAPHOCLIMATIC REQUIREMENTS
- Temperature: Most of the plants have tropical or subtropical origin, so it requires a more or less constant temperature of 18-20 ° C. it will not be favoured by the cold because it suffers with it. Sudden changes are harmful to it.
- Light: Usually need good light but not direct sunlight; in cold areas, it may be exposed to sunlight all day. Thus, depending on the species, the light needed vary between 20,000 lux for F. pumila and F. elastica 50,000-70,000 lux and F. rubiginosa, but typically 25,000-35,000 lux levels (except climbing and hanging). In F. benjamina excessively low light causes defoliation of the lower parts.
- Soil / Substrate: In general, it should be fairly loose and contain lots of peat and organic matter; must be neutralized with calcium. A suitable substrate would consist of: 3 parts of peat, 2 parts of topsoil and one part of sand. Depending on the type of substrate, calcium carbonate is added until a pH of 6 is reached.
- Humidity: As a plant of tropical and subtropical origin, it requires high humidity of about 75-80%.
- Irrigation: Too much water is not good for ficus because it causes falling of lower leaves. Scarce irrigation is more recommended. At first, it should be watered slightly until the plants are accustomed to their new environment. In summer, irrigation should be plentiful.
Although ficus can be propagated by seed, this method is not the most appropriate due to the short duration of germination and the plants produced though this method have their first leaves much smaller than normal, thus reducing their commercial value. From a commercial point of view, there are three propagation methods.
1. By cuttings
- For species groups 2 and 3, the most used method is the propagation by cuttings with 3-4 leaves, in an ambient temperature of about 25-30°C, with good ventilation, high brightness and fog or better under tunnel . These cuttings normally develop faster and give more perfect plants.
- If there are no enough plant material, multiplication by stem cuttings with a leaf and bud can be used: the cutting should have a complete internodes, removing the lower leaves and leaving only the top, which will be winded with a rubber band or something similar in order to reduce evapotranspiration. In F. elastic, sometimes this method is used especially in the types of variegated leaves. The cuttings are inserted vertically into a bowl of water, keeping them in one or two hours to remove and dry the latex (sap). Mother or stock plants should be blunted or should be applied with cytokinins to induce axillary shoots.
The best substrate for placing the cuttings into trays is sterilized sand, as it facilitates the chopping without damaging the roots. They can also be rooted directly in pots as is often done with the climbing and hanging types. They are placed in each pots several 2-3 knots cuttings with leaves and once rooted under tunnel or mist, they are arranged in tables or in corridors as hanging plants.
The most suitable season for propagation by cuttings is from December to March, as it allows a maximum period of greatest brightness, but with bottom heat.
The capacity and speed of rooting will be conditioned mainly by: the nutritional and health status of the mother plant, the state of hardening of the stems and whether they are in active growth. The fertilization of the mother plant should be kept constant and with a slightly favourable to potassium fertilization balance.
Generally, the rooting occurs at 4 to 5 weeks for most species. The application of hormones that promote this process can also be used.
2. By air layering
Air-layering is done by making an annular incision on the stem, which can be wrapped with neutralized peat with adequate fertilizer and moisture, and all with a polyethylene sheet to prevent water loss.
3. Propagation in vitro
The plants obtained by this method tend to be more compact and they branch easily from below. Terminal stem cuttings of plants obtained by propagation in vitro often root more easily. This technique has been used for several species: F. benjamina, F. lyrata, F. elastica, F. rubiginosa, etc.
5. GROWING TECHNIQUES
Fertilization: they are very demanding plants especially in compost and calcium. Boron and manganese deficiencies should be monitored. It goes well with a steady balance of 2: 1: 3 or 1: 1: 1, at the rate of 200-250 ppm. During the growth period, they must be fertilized every 15 days with full fertilization by irrigation.
Pruning: It should be done several operations. Among these is the removal of young shoots in order to foster the development of new branches. This pruning should be done in spring when the plant resumes its vegetative activity. On the other hand, if further intervention is needed, i.e. at the level of branches, it will be best done in late winter as the discharge or spill of latex or sap will be less.
6. PESTS AND ILLNESSES
Ficus is quite resistant to pests and plant diseases but can be attacked by:
- Red Spider: The spider mite attacks if the environment is very dry. Yellowish pits appear on the leaves, and these are subsequently folded upward obtaining a powdery aspect and can dry up and fall.
Affected leaves have yellowish zones at the upper part corresponding to the existence of colonies on the underside. Fine webs are seen on the undersides of the affected leaves.
To control this pest, it is recommendable to increase the humidity by using nebulisation procedure.
- Aphid: they cause twisted and deformed leaves that become sticky. Subsequently, the fungi take advantage of this situation, and black spots appear. Aphids are found in the buds.
- Mealybugs or cochineal: cause spots or red spots on the underside of leaves but sometimes also in stems.
The mealybug excretes a sugary liquid on which black spots appear.
To control this pest, methyl alcohol or a systemic insecticide be used. The procedure would be to remove the mealy bugs from the leaves with these products. Once this is done, the plant should be washed with soapy water.
In F. elastica, F. lyrata, mealybugs attacks are common in dry and warm weather.
- Thrips: this pest is difficult to control when the leaves are already bent. Thrips feed on the surface of young leaves and this causes leaf curl and purple pits. The cold stops the progress of the plague.
The control of this pest should be done before the leaves curl because it would be much more complicated for the phytosanitary products to kill the thrips once these are hidden in the folds of the leaves.
It is recommended to use blue colour traps and to eliminate infected plants and weeds. Also, if it is under plastic, it is useful to use an anti-thrip mesh and the use of natural enemies to combat biologically the pest.
Thrips attacks occur mostly in F. benjamina, F. elastica and F. retusa.
Among the diseases, fungal leaf spots of the genus Cercospora, Gloesporium and Corynespora and root fungal attack, especially in cold and waterlogged substrates are highlighted. Root nematodes can cause damage to F. benjamina.
It is recommended to remove the infected leaves. Fungicides can be used to control this disease.
Finally, in terms of physiopathology, these plants suffer when:
- Direct sunlight: Dried or burned leaves.
- Water imbalances (especially when the temperature is low): Yellowing of leaves. Overwatering is not convenient for this plant.
- Low-Light and wind currents: Defoliation
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