High-efficiency cultivation techniques for Chinese toon: a tutorial with a detailed explanation of the latest growing methods

Chinese toon, also known as Chinese mahogany sprouts, xiangchun, xiangzhuangtou, and dahongchunshu, among other names, has roots with a double layer of bark and is therefore also called chunbaipi. It originated in China and is widely distributed across regions north and south of the Yangtze River. It belongs to the Meliaceae family and is a deciduous tree with separate male and female plants. Its leaves are even-pinnately compound, its inflorescences are panicles, its bisexual flowers are white, and its fruit is an oval capsule with winged seeds that can be used for propagation. The tree is tall and, in addition to providing edible young shoots, is also an excellent choice for landscaping. The young shoots are nutritious and have dietary therapeutic effects, chiefly used to treat externally contracted wind-cold, wind-damp impediment pain, stomach pain, and dysentery. Chinese toon is a tall arbor tree native to China. The practice of eating Chinese toon shoots has long been customary, and by the Han Dynasty it had spread across both north and south of the Yangtze River.

Chinese Toon Propagation Techniques

There are seed raising, stem cutting, root cutting, and root sucker propagation.

1. Seed raising. Chinese toon seeds are small, with a hard seed coat and membranous long wings, so direct sowing makes it difficult for them to absorb water and germinate. To obtain uniform emergence, seeds need to be pre-germinated before sowing. The methods are:

① Soaking seeds in warm water. In early March, soak the seeds in warm water at 30-40°C for a full day and night. After the seeds have absorbed enough water, remove them and place them in a bulrush bag, then keep them at 20-25°C for germination, watering once each morning and evening and turning them evenly. Once more than 50% of the seeds have sprouted white, they can be sown.

② Germination. Mix the seeds with river sand at a ratio of 1:2, and sprinkle in an appropriate amount of clean water. The moisture level should be such that a handful held in the hand forms a ball and crumbles when the hand is released. Pile the sand-mixed seeds together in the shape of a steamed bun, water lightly each day, and turn them evenly from time to time. Once 70% of the seeds have sprouted white, they can be sown.

2. Stem cutting. From after leaf fall in autumn to April-May of the following year, select 1-2 year old branches, cut them into 20 cm long cuttings, and insert them into a prepared seedbed at a row spacing of 25×15 cm, with 1/3 exposed above ground.

3. Root cutting propagation. When transplanting and planting out, cut off the overly long main and lateral roots of the plant, cut them into 15-20 cm small sections, open furrows about 7 cm deep in the prepared seedbed at a row spacing of 25 cm, lay the roots horizontally in the furrows at a spacing of 10 cm, cover with soil and press firm, then water. When the shoots are 10 cm tall, remove suckers promptly and pay attention to cultivating and weeding.

4. Root sucker propagation. The roots of Chinese toon have many adventitious buds. Under natural conditions, some small young saplings often sprout around the tree crown and can be dug out and transplanted to cultivate new plants. However, natural suckering is limited, so artificial root cutting and suckering can be used for propagation. The method: after the soil thaws in early spring and before budding, dig a trench 50-60 cm from the outer edge of the tree crown, cut off the root tips, and fill the trench back with soil. This can stimulate the root tips to form a large number of sucker shoots and sprout new plants, which can be transplanted the following year.

5. Seedbed preparation. Choose flat terrain with fertile soil and good drainage, using sandy loam as the seedbed. Apply 4000 kg of fully decomposed organic fertilizer, spread it evenly, plow and turn, then break it up finely and level it. Make beds 1.2 m wide with deep furrows and high ridges. For seed sowing, open shallow furrows 5 cm deep at a row spacing of 20 cm, water thoroughly in the furrows, and after the water infiltrates, evenly scatter the pre-germinated seeds in the furrows, using 1.5-2 kg of dry seed per mu, cover with 2-3 cm of soil, then cover the bed surface with plastic film, covering tightly and pressing firm, so as to raise soil temperature and promote earlier emergence.

6. Seedling stage management

① After the seeds germinate and emerge, immediately remove the plastic film in the evening, water lightly once, and take care to keep the bed surface moist.

② Thin and even out the seedlings in good time, removing those that are too dense as well as merged, weak, and diseased seedlings, keeping a plant spacing of 3-5 cm. Along with pulling weeds in the field, apply 10 kg per mu of diammonium phosphate as a top dressing, water thoroughly once, and loosen the soil shallowly, taking care not to damage the roots.

③ Thinning and transplanting. From late May to early June, when the seedlings have 4-6 true leaves and are 8-10 cm tall, thinning and transplanting are needed to improve light and soil nutrient conditions for the seedlings, at a spacing of 10-15 cm, following the principle of keeping the strong and removing the weak, and keeping the sturdy and removing the slender. Water the bed surface thoroughly one day before thinning so that pulling the seedlings damages the roots as little as possible. Transplant the strong seedlings removed during thinning to the prepared seedbed at a row spacing of 25×15 cm in good time, and water to settle the roots to promote survival.

④ After transplanting and survival, and after cutting propagation has produced young plants, apply fertilizer and water in good time, and cultivate and weed to promote seedling growth. In the later stage, control plant height, adjust plant shape, increase nutrient reserves in the seedlings, and promote the formation of plump terminal buds through measures such as pinching, spraying paclobutrazol, or fertilizer and water management.

Chinese Toon Field Planting

Planting can be carried out from after leaf fall to before budding in early spring of the following year. Before planting, apply 4000 kg of decomposed organic fertilizer per mu of field, spread it evenly and plow deeply, make beds 2-2.5 m wide, and plant at a row spacing of 60-70×15-20 cm (dwarf dense planting), with 6000-8000 plants per mu, reaching more than 10,000 plants at the highest. After planting, water thoroughly in good time to settle the roots and promote survival.

Field Management

1. Fertilizer and water

After planting and survival, apply fertilizer and water in good time, and combine with cultivating and weeding to promote rapid seedling growth.

2. Pest and disease control

The pests of Chinese toon include Chinese toon caterpillars, slug moths, and cloud-banded longhorn beetles. During the larval stage, they can be sprayed and killed with 800-fold trichlorfon solution, and during the adult stage, they can be controlled with 1500-fold dimethoate. Diseases include leaf rust and powdery mildew, which can be controlled with 500-fold triadimefon. Clean the field in winter to reduce the overwintering base of pests and diseases.

3. Pruning

Each spring after the harvest of Chinese toon shoots is finished, from mid-to-late June to early July, prune the main trunk (behead it) at 20 cm above the ground to promote lateral buds to sprout into new branches. From late July to early August, pinch the tops according to the vigor of the new branches. Those with strong growth can be topped earlier, and conversely, topping can be delayed. Combine this with fertilizer and water management to promote the formation of plump terminal buds. The growth period of Chinese toon shoots is short, so they should be eaten early, fresh, and tender. There is a saying: "Chinese toon shoots before the rain are as tender as silk, and after the rain they are like wood." The harvest standard is preferably purple-red bud color and a bud length of 10-15 cm. When harvesting, pick the terminal buds first and then the lateral buds, because if the terminal buds are not harvested, the lower lateral buds will be difficult to grow or will grow poorly. When picking shoots, gently twist them off by hand at the base of the leaf stalk, tie them into small bundles of 100-200 grams, put them in plastic bags and seal them to prevent water loss and wilting, and improve market quality. Chinese toon shoots can be harvested 3-4 times each year, with a yield of 400-500 kg.

Overwintering Protection Measures for Chinese Toon

Using plastic greenhouses to protect Chinese toon for overwintering cultivation: after leaf fall in autumn, dig out the transplanted Chinese toon plants together with their roots, tie every 50 plants into one bundle, pour mud slurry on the roots, and heel them in in a shady place. The method: in mid-to-late November, dig a trench 50-60 cm deep and 50 cm wide behind a house, stand the bundled plants upright at a slant in the trench, fill the roots level with soil, water thoroughly once, to the extent that the water infiltrates to the bottom of the trench, and keep moist afterward. After about 15 days of low temperature, they pass through the dormant period. Then plant them in the prepared greenhouse (row and plant spacing the same as above). Inside the greenhouse, maintain the daytime temperature at 18-24°C and the nighttime temperature at 12-14°C. After 40-50 days, the first batch of Chinese toon shoots can be harvested and marketed. Protected cultivation should strengthen fertilizer and water management to increase the yield of Chinese toon shoots.

Processing, Salting, and Storage

After processing and salting, Chinese toon shoots can be stored for a long time and transported out at any time. The method is simple and easy to carry out. Harvest fresh Chinese toon shoots, wash them with water, and after drying in the shade, add 20 kg of salt per 100 kg. In a vat, place one layer of Chinese toon shoots and one layer of salt, with less salt in the lower layers and more in the upper layers. After 3-4 hours, turn the contents of the vat, and after another 5-6 hours, turn them a second time, turning 5-6 times in total. After about 20-30 days, they are ready. Take them out and spread them to dry for 1-2 days, add a small amount of rice vinegar to increase gloss and crispness, then sun-dry until 50-60% dry. Tie them into small bundles of 100-150 grams, put them into small-mouthed jars, arrange tightly and press firm, seal and store, and they can be kept for 2-3 years.