The Latest Eucommia Planting Techniques and Methods Tutorial

Eucommia is native to central and southwestern China and is a species endemic to China. Eucommia has been introduced to botanical gardens across Europe and America, where it is called the “Chinese rubber tree,” although it has no kinship whatsoever with the rubber tree. The bark of the Eucommia tree can be used as medicine, its seeds contain 27% oil, and its wood is used for construction and making furniture, making it a plant of great planting value.

Growing Environment

In its natural state, Eucommia grows in low mountains at an altitude of 300-500 m, in valleys or open woodlands on low slopes. It is not strict about soil choice and can grow in poor red soil or on rocky cliffs. It prefers a sunny, mild and humid climate and is cold-resistant. It is not demanding about soil and can be planted on hills and plains, and can also be grown on scattered plots of land or around the home. Eucommia is cold-resistant and can withstand low temperatures of at least −30℃.

Propagation Methods

Eucommia can be propagated 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℃. Generally, warm regions are suitable for winter sowing, while cold regions can sow in autumn or spring, 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℃ warm water for 2-3 days, changing the water 1-2 times a day, then remove them after the seeds 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 one-year-old 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℃, they can root after 15-30 days. If the cuttings are treated with 0.05 ml/L naphthalene acetic 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 for 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 layer them into the soil to a depth of 15 cm. When the suckers grow to 7-10 cm tall, earth up and press firm. After 15-30 days, new roots can form at the base of the suckers. In late autumn or the following spring, dig them up, separate the suckers one by one and plant them out.

5. Grafting propagation: Use two-year-old seedlings as rootstock and select one-year-old branches from superior mother trees as scions. Graft them onto the rootstock by cleft grafting in early spring, and the survival rate can reach more than 90%.

Sowing and Raising Seedlings

1. Preparation before sowing

Put the seeds into plastic woven souvenir bags and hang them in a ventilated, cool place, then sow them directly into the beds in late December. After Eucommia seeds are collected at the end of October, hang and store them. In late December, soak them in clean water for 1-2 days, changing the clean water once a day. At the last water change, add a small amount of copper sulfate or amobam (zinc) or carbendazim to kill pathogens. Remove the seeds and filter them until they can be scattered by hand without sticking when sowing, then sow directly into the beds. The lifespan of Eucommia seeds is 1 year. The seed germination rate is closely related to maturity and freshness. Over-mature seeds have a low germination rate, and the germination rate for spring sowing is even lower.

2. Land preparation and fertilization

Choose sandy fields or sandy loam fields and plough and harrow repeatedly 2-3 times before sowing. Before the last ploughing and harrowing, apply compound fertilizer as a “stubble-opening” application. Make beds 1 m wide, dig trenches 20-25 cm deep, apply barnyard manure or broadcast compound fertilizer and rapeseed cake in the trenches, or use human and livestock urine and manure as a base, then cover with soil 1.5-2 cm below the bed surface.

3. Sowing into the beds

In the trenches already supplied with base fertilizer, place 1 seed every 5 cm or scatter them thinly and evenly in the trenches, and pick up those that are too dense and place them sparsely elsewhere. Cover with plant ash mixed with soil or fine soil to 1.5-2 cm. On the beds, lay rice straw or thatch flat along the trench direction for insulation. The covering grass does not need to be too thick, so as to avoid pulling out seedlings along with the grass when it is removed after the seedlings are fully emerged.

4. Rodent control, insect control and disease prevention

After the beds are covered with rice straw, mice are attracted very quickly, and mice gnawing and eating Eucommia seeds is extremely serious. Poison bait must be placed immediately to kill the mice. 15-20 days before the seedlings emerge, mix carbofuran and loess in a 1:3 ratio and scatter it on the bed surface to poison cutworms. Once the seedlings have basically all emerged, remove the rice straw and thatch, then scatter once more a mixture of 1:4 Shouchen Baichong powder, plant ash and fine soil. For shriveled seeds, or seeds whose inner flesh is black because Eucommia seed filling was hit by drought, do not take the gambler's chance of “just sow and see,” and even less should they be raised together with plump seeds, to prevent the plump seedlings from being infected with damping-off after emergence.