How to grow Eucommia ulmoides? A detailed guide to the cultivation techniques of the Chinese medicinal herb Eucommia ulmoides
Site selection and land preparation
Choose a sunny gentle slope with deep, loose, fertile soil that is acidic to alkaline and well-drained. Deeply plow the soil, rake it level, and dig holes at a spacing of 2-2.5 m × 3 m, 30 cm deep and 80 cm square. Into each hole apply 2.5 kg of farmyard manure, 0.2 kg of cake fertilizer, 0.2 kg of bone meal or superphosphate, and burnt soil ash, etc., mix thoroughly with the soil in the hole, and set aside for planting. For the seedbed, break up the soil fine, rake it level, and make raised beds 1.2 m wide.
Planting methods
Propagation can be done by seed, cuttings, layering, and grafting. In production, seed propagation is the main method. (1) Seed propagation: It is best to select fresh, plump, yellow-brown, glossy seeds and sow them in winter from November to December or in spring from February to March when the average monthly temperature reaches above 10°C. Generally, warm regions are suitable for winter sowing, while cold regions can use autumn sowing or spring sowing, so as to meet the low-temperature conditions required for seed germination. Seeds should not be dried, so it is best to sow them while fresh. If spring sowing is needed, the seeds should be stratified after collection, with a seed-to-moist-sand ratio of 1:10. Alternatively, before sowing, soak the seeds in 20°C warm water for 2-3 days, changing the water 1-2 times a day, then remove them after they swell, dry them slightly, and sow, which can increase the germination rate. Drill sowing, with a row spacing of 20-25 cm, using 8-10 kg of seed per mu. After sowing, cover with grass and keep the soil moist to facilitate seed germination. After the seedlings emerge, remove the covering grass on cloudy days. Each mu can produce 30,000-40,000 seedlings.
(2) Softwood cutting propagation: At the turn of spring and summer, cut current-year softwood shoots into 5-6 cm cuttings and insert them into the seedbed to a depth of 2-3 cm. At a soil temperature of 21-25°C, roots can form after 15-30 days. If the cuttings are treated with 50 mg/kg naphthaleneacetic acid for 24 hours, the survival rate of the cuttings can reach more than 80%.
(3) Root cutting propagation: When seedlings are lifted from the nursery, prune the seedling roots and take roots 1-2 cm in diameter, cut them into 10-15 cm root segments, and insert them as cuttings, with the thick end slightly exposed above the ground. New shoots can sprout below the cut surface, and the seedling formation rate can reach more than 95%.
(4) Layering propagation: In spring, select strong branches and bury them in the soil to a depth of 15 cm. When the sprouts grow to 7-10 cm tall, earth up and press firm. After 15-30 days, new roots can form at the base of the sprouts. In late autumn or the following spring, dig them up, separate the sprouts one by one, and they can be planted out.
(5) Grafting propagation: Use 2-year-old seedlings as rootstock and select current-year branches from superior mother trees as scions. In early spring, cleft-graft them onto the rootstock; the survival rate can reach more than 90%. Field management
(1) Seedling stage management: After the seeds emerge, pay attention to cultivating and weeding, watering, and fertilizing. Seedlings are sensitive to strong sunlight, so appropriate shading is needed. In the dry season, spray irrigation should be done in time to prevent drought, and in the rainy season, attention should be paid to preventing waterlogging. In combination with cultivating and weeding, topdress 4-5 times, each time applying 1-1.5 kg of urea per mu, or 3,000-4,000 kg of decomposed dilute manure. If the trunk of a seedling is crooked, in early spring all the aboveground part can be removed along the ground surface to promote new branches, and from them select 1 strong, vigorous, straight new branch as the new trunk, removing all the rest.
(2) Planting out: When 1-2-year-old seedlings reach more than 1 m in height, they can be planted out after leaf fall and before bud break the following spring. According to the above spacing, plant 1 seedling per hole. Young trees grow slowly, so tending should be strengthened. Every spring and summer, cultivating and weeding should be carried out, together with fertilization. In autumn or the following spring, basal branches should be removed in time, and crossing and overly dense branches should be pruned. For mature trees, topdressing should also be applied as appropriate. In northern regions, stop fertilizing in August to avoid overly vigorous late growth that reduces cold resistance.