Star anise is propagated mainly from seeds. Seeds are selected from ripe fruits during the harvest season (July – September), from strong, fruitful trees and have good resistance to pests, diseases. The collected fruits should be spread in a thin layer in a cool, shady place for 4-5 days, to separate seeds. Star anise seeds contain fatty oils and lose their germinating ability quickly; therefore, they should be sown immediately after collection or stored in moist sand. The longer the storage period, the lower the germination seed rate.
Nurseries need to choose light clay, red, much humus, enough moisture soil. Before sowing, it is necessary to plow carefully, clean the grass, apply decomposed organic fertilizer (40-60 tons/ha), handle fungicides. To gain well-germinated seeds, before sowing, soak seeds in warm water (35-37C) for 2-3 hours. Seeds can be sown in canals, scattered or sowed into soil pots, 1kg of seed can be sown on an area of 80-100m2. After sowing, it should be covered with a thin layer of straw or thatched grass and watered with enough moisture. Depending on weather conditions, seeds may germinate after sowing from 15-90 days. At this time it is necessary to gradually remove the covering layer of straw and make the shade cover 50-60 cm high. Covering is needed for the first time, then gradually reduces the cover base on the level of plant growth. In nurseries, need to clean grass, moist enough, apply additional fertilizer to prevent the fungus from damaging roots and young roots. About 18-20 months after sowing, the seedlings are 50-70cm tall. This is the time to transfer seedlings to plant on production areas.
The best planting season is spring or rainy season. Star anise should be grown in hillsides with relatively thick topsoil, nutritious, with a pH of 5-6. Planting holes need to dig 50-60cm deep, 50-60cm wide, apply 15-20kg of decomposed animal manure, and clean the surrounding grass. After planting, water to keep moisture and shade. Should keep existing forest trees around to shade trees.
In order for star anise to develop well and supply high fruit yield, annual organic fertilizer is required:
+ NPK (about 15-20 kg/tree) in the period before flowering and after harvesting fruits. When fertilizing, it is necessary to dig trenches around the canopy, spread fertilizer, and fill up the ground, clear grass, remove vines, surrounding shrubs, and root. Good fertilizing, plants grow, develop smoothly, fruit yield will be high.
So far there is no information about pests and diseases in star anise. Some documents refer to nematodes (Radopholus similis) that are harmful to some individuals in some areas.
At 5-6 years of age, the fruit yield is very low, usually only 0.5-1 kg/tree. By the time of reaching 10-20 years, the average fruit yield can reach 7-20 kg/tree. From 20 years of age onwards, the tree starts to produce stable fruits, usually reaching 20-30 kg/tree, the year of the bumper can reach 35-40 kg/tree (maximum yield can reach 45-50 kg/tree). If well cared for, yielding high and stable yields can last between 20 and 80 years of age. Then productivity will decrease. The cultivation cycle can reach 90-100 years.
Exploiting, processing and preserving
After harvesting, fruits need to be dried immediately since they are prone to mold. Can also soak in boiling water for a few minutes to kill yeast and then exposed. With this method, the fruit is red and beautiful, but the content of essential oils has decreased slightly. Usually, every 100 kg of fresh fruit after drying will give about 25-30kg dry.
On the market, dried star anise fruit is divided into 3 categories:
– Type 1: full fruit 8 big wings, evenly, not being flattened, red-brown, short stalks (3-5 mm), not moldy.
– Type 2: the fruit has irregular wings, cockroach color, some wings are flattened, broken.
– Type 3: young fruits, small fruits, dark brown.
Star anise is usually consumed in the form of dried fruits or essential oil products. Essential oils may be stored when the fruit is fresh or dried. Ethnic minorities in Lang Son often distilled star anise essential oil in manual distillers, simple, similar to distilling alcohol. Storage time can last from 18-24 hours. For high performance and quality of essential oils, continuous steam distillation apparatus with refluxing is required. The residual residue after the distillation of essential oils can be used as fuel for boiling or composting with animal manure to fertilize crops.