(Left) A potted Star Fruit growing in a township garden. (right) Fruits hanging from a branch

One of the most curious-looking fruits grown in Salt Lake is the Star Fruit. The thin-fleshed yellow fruit that is actually known as Carambola (Kamranga), but since in cross section it would resembles a star, it is commonly known as Star Fruit.

Carambola is very popular in South America, south China and Taiwan and is cultivated throughout India, Bangladesh, Sri Lanka, Malaysia, Indonesia and Philippines. It has been growing in the Indian subcontinent for hundreds of years yet the origin of this tree is unknown.

The Star Fruit is a woody plant scientifically known as Averrhoa Carambola and belongs the Oxaliadacea family. It is a small tree with drooping branches that reaches up to a height of four to 6m. The tree appears to be very decorative due to its ornamental foliage. It bears attractive golden-yellow oval-elliptic fruits measuring about two to five inches in length. It usually has five prominent longitudinal ridges but occasionally it has four. The skin of the fruit is thin and turns light to dark yellow when ripe and the flesh is translucent and light yellow in colour.

Garden enthusiasts sometimes grow Carambola for it red to purple flowers which have white edges and for its unusually shaped fruits. It is cultivated commercially in some parts of India but it is not economically significant. In Salt Lake it is mostly cultivated as ornamental pot plants and will be discussed later in this column.

Cultivation: Carambola trees are seldom planted in an orchard scale. When one plans to grow Carambolas in a regular orchard they should be planted at least 20-ft apart from each other. They can be grown at up to 4,000-ft from sea level.

The plant prefers warm, moist climate and well-distributed rainfall encourages normal growth and cropping. It doesn't have a soil type preference. Star Fruits can grow on any type of soil with good drainage but it prefers acidic soil. For cultivating them in containers they need regular attention if they are to flourish.

Plant the Carambola in a container that is only three to four inches larger than the existing root ball. The size of the container can be increased gradually during re-potting. Ultimately a container measuring 18 inches in diameter and 15 to 18 inches in depth would be required.

Use a nutrient-rich soil based compost for the plant. Give the plants a nitrogen-rich fertiliser just before the rains. Top dress, that is apply fertiliser on the surface of the soil, in case of established plants. Do this by removing one to two inches of compost and replacing it with garden compost. This general regime, combined with regular watering and prompt attention to problems, should ensure that fruits grow well.

Generally the Carambola tree flowers throughout the year with April to June and October to December being the main fruiting seasons.

Varieties: There are some specific Indian varieties which are not recognised as Carambolas but two main types are distinguished: the small, sour type and the larger, sweet type. Now-a-days a number of cultivars have been developed for commercial cultivation. These are very sweet varieties such as the Fwang Tung of Thailand, Tean Ma and Min Tao of Taiwan and Maha of Malaysia. Some of these varieties are available in Calcutta too.

Propagation: The Carambola is often propagated through seeds but for producing true-to-type plants propagation by budding, grafting and layering are suggested. In case of propagation through seeds, the fresh seeds are cleaned, dried and sown in pots. The seedlings are transplanted into individual pots or plastic bags and then allowed to harden. They are then transplanted.

After care and fertilisation: In case of orchards, they need to be cleaned from time to time and the watering of young plants is very important. Practically no specific training or pruning operation is advocated for Carambola trees but the undesirable, weak and diseased branches should be removed for healthy growth.

It is a good practice to use manure for the trees once a year with farmyard manure. Also apply some nitrogenous and phosphetic fertilisers, the dose depending upon the age and size of the tree and the fertility of the soil. For container-grown plants where the volume of compost is limited, liquid feeding will give better results.

Liquid feeds supply nutrients in a more readily-available form and can be applied as a foliar spray. But the amount of feed and the frequency at which it is to be applied depends on the richness of the growing media used, the volume of the container and how vigorously the plant is growing.

Usage: The ripe sweet variety of Star Fruits may be eaten fresh. The flesh is crunchy firm and extremely juicy. Fruits picked while still green will turn yellow in storage at room temperature. Star Fruits are best consumed shortly after they ripen.

The sour fruits are used for making pickles or as a substitute of tamarind. Good quality of squash, jelly, preserves and candy can also be prepared from them. With proper packing, fruits of Carambola will ship well but at present they are mostly supplied to nearby market.

nTo be continued

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