Detailed Guide to Caoguo Cultivation Techniques: Scientific Planting Methods and Management Key Points
Caoguo, also known as Caoguo kernel or Caoguo fruit. It has the functions of drying dampness and dispelling cold, resolving phlegm and treating malaria, and promoting digestion and relieving food stagnation. It is mainly used to treat malaria, phlegm-fluid retention with stuffiness and fullness, cold pain in the epigastrium and abdomen, nausea, vomiting, diarrhea and dysentery, and food stagnation. Domestically, in addition to relying on harvesting wild resources, it still needs to be imported from abroad. Caoguo is mainly distributed in Vietnam. In China, it is produced in Guangxi and Yunnan.
Morphological Characteristics
Perennial herbaceous plant. The plant is 2-2.5 m tall, with a thick, jointed horizontal rhizome, and upright, clustered aerial stems. Leaves are arranged in 2 rows; the leaf blade is long-elliptic or narrowly oblong, gradually pointed at the tip, gradually narrowed at the base, with entire margins, smooth and hairless on both surfaces; the leaf sheath is open and clasping the stem; the ligule is 0.8-1.2 cm long; the spike emerges from the rhizome, with 5-30 flowers per inflorescence, yellow or red; capsules are densely arranged, oblong or ovate-elliptic, with a persistent style at the apex, red when ripe, with irregular wrinkles on the outer surface and angular seeds inside. Flowering period is April-May, fruiting period is June-November.
I. Growth Habits
It prefers a warm and shady mountainous climate environment. An annual average temperature of 18-20°C is suitable; when the absolute minimum temperature is 1°C, no frost damage occurs. It likes moisture and fears drought. If rainfall is moderate during the flowering season, there will be many fruits and a high fruit retention rate; if rainfall is excessive, it will cause flower rot and no fruiting; if drought occurs during the flowering season, most flowers will dry up and fail to set fruit. Caoguo is a shade plant and cannot tolerate strong sunlight; it prefers an environment shaded by trees, generally with a canopy density of 50-60% as suitable. As for soil, slightly acidic fertile soil in moist, shaded valley sparse forests with rich humus and loose texture is suitable.
II. Site Selection and Land Preparation
It is advisable to choose valley slopes, stream sides, or under sparse forests, with sandy loam soil rich in humus and loose in texture; poor soil and heavy clay soil are not suitable for planting. On the selected forest land, weeds and shrubs should be cleared, and excessively dense trees should also be thinned to adjust the canopy density to 50%-60%, and the soil should be turned to a depth of 20-27 cm. Make beds 1.2-1.5 m wide. At a height of four cm, dig holes in the beds according to the spacing between plants and rows; the hole specifications are 40 cm x 40 cm x 30 cm. Apply compost, farmyard manure, and burnt soil as base fertilizer in the holes, mix well with topsoil, and then wait for planting.
III. Sowing
Propagation methods: use seeds and division propagation.
1. Seed propagation
(1) Seed selection: select high-yield plants with large fruits, plump seeds, and no pests or diseases as seed collection plants. (2) Seed collection and seed treatment: when the fruit peel is purplish red, the seeds are silver-gray, and the fruit tastes sweet when chewed, pick it, then select plump, fully mature fruits free of pests and diseases as seeds; it is best to sow immediately after collection. Before sowing, first peel off the fruit skin, wash off the flesh, soak the seeds in clean water for 10-12 hours, then place coarse sand and seeds in a bamboo basket and rub thoroughly until the aril is rubbed off. Alternatively, mix the seeds with 30% plant ash, rub the seeds apart by hand, remove the surface gelatinous layer, and then sow or dry them for storage until sowing in the following spring. (3) Sowing time: sow immediately after collection; both spring and autumn are acceptable, with autumn sowing being better. Spring sowing should be carried out when the temperature rises above 18°C; for autumn sowing, when the monthly average temperature is above 18-20°C, a large number of seeds will sprout and emerge within 1 month. After sowing, the germination rate can reach more than 80% in 40-50 days, and more than 90% from December to February of the following year. (4) Sowing method: when sowing, open furrows on the bed at a row spacing of 15-20 cm, place seeds at a plant spacing of about 6 cm, with a sowing depth of 1.5-2 cm; after sowing, cover with soil, mulch with grass, and water. Seedlings can be transplanted after half a year of raising.
2. Division propagation
In spring, before new buds begin to sprout and have not yet emerged from the soil, select robust one-year-old divisions from the mother clump, cut off the lower leaves, and keep 2-3 upper leaves to reduce water evaporation. Dig up the rhizome with buds, cut it into lengths of 7-10 cm, and plant after cutting. Open holes at a spacing of 1.3 m x 1.7 m; the planting hole specifications are 50 cm x 50 cm x 40 cm. Plant 1 clump per hole, cover with soil and press firmly, and water thoroughly to settle the roots.
IV. Field Management
1. Shading: uncover the grass immediately after seedlings emerge; if the canopy density is insufficient, simple shade frames can be set up for shading.
2. Cultivation and weeding: after planting, carry out cultivation and weeding once each year from April to June; at the last weeding, cut off old plants and diseased plants that died after fruiting.
3. Topdressing: production areas with conditions should topdress multiple times each year. In early spring, use fine chicken manure mixed with plant ash and scatter it around the plants; in summer when flowering just begins, scatter plant ash on the leaf surfaces before the morning dew dries as foliar topdressing; in early winter after harvesting the fruit, place farmyard manure and burnt soil around the roots. It can also be combined with cultivation and weeding by opening ring-shaped furrows for topdressing.
4. Earthing up: after Caoguo is planted and before flowering, earthing up should be carried out to make young buds grow robustly; after flowering, do not earth up immediately, so as to avoid smothering and injuring flower buds, causing rot and no fruiting. During each weeding, if fibrous roots are found exposed on the surface, a small amount of humus soil can be earthed up at the fibrous roots to help the roots absorb nutrients.
5. Drainage and irrigation: when spherical flower buds appear at the roots and drought occurs, irrigate in time; when there is too much rain, attention should be paid to drainage to avoid damaging the flower buds. At the same time, remove debris around the flower buds to provide ventilation and light, so as to avoid flower drop and fruit rot.
6. Adjusting canopy density: Caoguo needs a certain amount of shade throughout its growth and development stages. When tree growth causes insufficient light transmission in the forest, appropriate thinning or pruning should be carried out so that the canopy density is controlled at 50%-60%, to facilitate the growth of new plants.
V. Pest and Disease Control
Damping-off: harms seedlings, occurs from March to April, and in severe cases can cause large areas of seedling collapse. Control methods: (1) disinfect the soil with 70% quintozene before sowing; (2) after seedlings emerge, use 1:1:120 Bordeaux mixture for prevention; (3) after disease occurs, pull out diseased plants, scatter lime powder around the diseased plants, and spray with 50% carbendazim 1000-fold solution once every 7 days, continuously spraying 2-3 times.
Stem borer: harms the stems of Caoguo. Control method: when insect damage is found, promptly prune off plants with dead hearts, and spray with 50% fenitrothion emulsifiable concentrate diluted 800-1000 times.
VI. Harvesting and Processing
Caoguo blooms and fruits after 2 years of planting, and generally enters the mass fruiting period only after 6-7 years. After the Beginning of Autumn, from September to October, the fruits mature and are harvested when they turn grayish brown but have not yet split. The picked fruits should be directly sun-dried or dried over a low fire, otherwise they are prone to mildew and deterioration. When drying over fire, the heat must be controlled; too much fire will scorch them, while too little fire will produce moldy Caoguo. Therefore, during drying, the heat should be even, the furnace temperature should be maintained between 50-60°C, and they should be turned frequently so they are heated evenly. Fresh fruits can also be placed in boiling water and blanched for 2-3 minutes, taken out and sun-dried, then baked over a gentle fire to obtain dried fruits.