Key Technical Points for Establishing a High-Density, High-Yield Honeysuckle Plantation

Honeysuckle (Lonicera japonica) is a perennial semi-evergreen woody vine, also known as Erhua or Shuanghua, and is a traditional valuable Chinese medicinal herb. The roots, stems, leaves and flowers of honeysuckle can all be used medicinally, but the main medicinal part is the dried flower buds, which have the effects of clearing heat and detoxifying, eliminating chronic inflammation and improving human immunity.

In recent years, with the intensification of honeysuckle development and the broadening of its application fields, market demand has grown steadily larger. Improving cultivation techniques to raise the early-stage yield of honeysuckle and maintain the duration of the full-production period has become a major problem urgently needing solution in production.

In recent years, based on the characteristics of honeysuckle cutting seedlings - a short purely vegetative growth period and the concurrent progression of vegetative and reproductive growth - we have adopted measures such as increasing the initial planting density and, after one year, gradually thinning according to growth conditions and available space. This has not only greatly increased the early-stage yield of honeysuckle, bringing it into the full-production period 2 to 3 years earlier, but also, after entering the full-production period, plant growth is basically unaffected. Space utilization remains relatively reasonable, making full use of land, space and climatic resources, greatly improving comprehensive benefits, and overcoming the shortcomings of pure high-density plantations (high early-stage yield but declining later yield) and sparse plantations (late entry into the full-production period and low early-stage yield). The key technical points are described below.

1. Planting Time

Honeysuckle can be planted in all four seasons. The survival rate is relatively high when planted from mid-September to mid-March of the following year, and in areas south of North China, autumn planting is preferable. Although air temperature drops noticeably during this period, soil temperature is still within the range suitable for root growth. Newly planted honeysuckle can heal damaged roots before the soil freezes and can produce a large number of new roots, resulting in a high survival rate, vigorous growth the following spring, a short recovery period and high flower yield. Although honeysuckle planted after the New Year can survive, sprouting and root healing and growth proceed simultaneously, causing a prominent conflict between the above-ground and below-ground parts in competing for nutrients and water, resulting in a long recovery period, poor early-stage growth and low flower yield in that year. In areas with severe winter cold, drought and water shortage, spring planting can be used to prevent desiccation.

2. Planting Patterns

1. Equal-row, equal-spacing pattern

In this pattern, after entering the full-production period, both the plant spacing and row spacing are 1.5-2 m, with 167-296 plants per 667 sq m. The initial planting density (667-1184 plants/667 sq m) is 4 times the full-bloom density. After one year, every other row is thinned, retaining 333-592 plants. After 2-3 years, every other plant is thinned, retaining 167-296 permanent plants. With this pattern, vegetables such as garlic, onion and spinach can be intercropped in the first year. The advantage of this pattern is that it ensures honeysuckle growth is unaffected by crops, with high early-stage yield: in the first year, the yield per 667 sq m can reach 10-20 kg, in the second year 30-40 kg, and in 3-4 years it enters the full-production period.

2. Wide-row, dense-plant pattern

In this pattern, after entering the full-production period, the row spacing is 1.8-2 m and the plant spacing is 1.6-2 m, with a density of 185-231 plants/667 sq m. The initial planting density (740-924 plants/667 sq m) is 4 times the full-bloom density. After one year, every other plant is thinned, retaining 370-462 plants per 667 sq m. After 2-3 years, a second thinning of every other plant is carried out, retaining the permanent plants. With this pattern, in the first year, besides intercropping vegetables between rows, low-stalk crops such as wheat and barley can also be intercropped, but the sowing width should not exceed 1 m so as not to affect honeysuckle growth. The advantage of this pattern is convenient field management, but honeysuckle growth is slightly affected by the crops.

3. Direct-cutting plantation establishment pattern

Vigorous branches with a diameter of more than 0.8 cm and a length of 35-40 cm are used as cuttings to replace seedlings for plantation establishment. The planting density and thinning steps are the same as patterns 1 and 2. The burial depth of the branches is 1/2 to 2/3 of the branch length. After burying, firm the soil and water thoroughly. A total of 2-3 waterings are given before overwintering, and before overwintering, soil is mounded up to protect against freezing and conserve moisture. When establishing a plantation by this method, the issue of replanting must be considered, so plants can be partially densified between plants or two plants per hole. The advantages of this pattern are: it can solve the problem of insufficient seedling sources. The disadvantages are: more frequent watering, incompatibility with intercrop management, and a slightly lower survival rate than using seedlings.

3. Main Technical Measures

1. Variety selection

There are many varieties of honeysuckle. The main excellent varieties cultivated in production are Fengqiu Damaohua and Shandong Jizhuahua. Fengqiu Damaohua is a variety under national origin protection, with an upright tree form, thick and strong branches, and easy shaping and pruning. The flower buds are 4-6 cm long, with a chlorogenic acid content of 5.6%-6.7%, coordinated medicinal components, resistance to pests and diseases, and strong adaptability. It can bear flowers in the same year after planting, and after entering the full-production period, it can yield 100-150 kg per 667 sq m, making it the preferred variety in production.

2. Plantation site selection

Honeysuckle is drought-tolerant, cold-tolerant, waterlogging-tolerant and barren-tolerant, and has low soil requirements. It can grow and flower normally in both slightly acidic and alkaline soils. However, to meet the requirements of high yield, high quality and pollution-free cultivation, the plantation site should be selected on plots with loose, fertile soil and convenient drainage and irrigation. It should also be far from cities, industrial and mining enterprises and major traffic routes, and the air, soil and irrigation water must be tested and meet national standards.

3. Fine land preparation

Before planting a high-density honeysuckle plantation, the land must be leveled, and sufficient basal fertilizer must be applied. Per 667 sq m, apply 4-5 cubic meters of high-quality decomposed organic fertilizer, 50 kg of superphosphate, 50 kg of ammonium bicarbonate, 10 kg of potassium sulfate and 1 kg of zinc sulfate. To eliminate underground pests, 1 kg of phoxim per 667 sq m can be mixed with fine sandy soil plus 20 kg and broadcast before plowing for soil treatment. The plowing depth is 25 cm, and harrowing follows plowing. Then beds 2-4 m wide are formed.

4. Use of strong seedlings

Strong seedlings are the foundation for improving the survival rate, advancing flower bud formation and achieving early high yield. At present, the standard for strong seedlings used in Fengqiu honeysuckle production is: thick and strong stems, short internodes, small hollow core, seedling height above 50 cm, old stump diameter above 0.8 cm, old stump length above 15 cm, new shoot base diameter above 0.5 cm, new shoot length above 30 cm, and more than 3 lateral roots above 15 cm. Using strong seedlings allows abundant flower bud formation in the same year and can bring the plants into the full-production period 2-3 years earlier.

5. Scientific planting

First, plan the planting points according to the determined row and plant spacing, then dig planting holes 50 cm square at the planting points, placing raw soil and topsoil separately. Apply 5-10 kg of decomposed organic fertilizer and 0.3-0.5 kg of superphosphate per hole. Mix the fertilizer evenly with the topsoil and fill it into the hole. Plant 1 plant per hole, at a depth slightly deeper than the seedling was in the nursery. After planting, firm the soil and water thoroughly with the planting water. After the water dries, cover with soil, slightly higher than the ground surface. To improve the survival rate and promote rapid recovery, generally water once more 2-3 weeks after planting, and thereafter water as conditions require.