Honeysuckle Cultivation Techniques and Planting Management Methods
Honeysuckle is the dried flower buds or just-opening flowers of the Caprifoliaceae plant Japanese honeysuckle (Lonicera japonica Thunb.). Also known as silver flower, double flower, and two-treasure flower. It has the effects of clearing heat and detoxifying, and dispelling wind-heat. Its stems can also be used as medicine, called honeysuckle stem, with the effects of clearing heat and detoxifying, and dispelling wind and unblocking collaterals. It is mainly produced in Shandong and Henan, and is produced in most parts of the country.
(I) Morphological characteristics
A perennial semi-evergreen twining shrub, with stems reaching up to 9 m in length. The stem is hollow and much branched; the bark of old branches is light purple and smooth; new branches are dark purplish-red, densely covered with short soft hairs. Leaves are simple and opposite, ovate or long-ovate; young leaves have short soft hairs, and the underside is grayish-green. Flowers are borne in pairs in the leaf axils; there are 2 bracts, leaf-like; both the pedicels and flowers have short soft hairs; the corolla is white when it first opens and turns golden yellow after 2-3 days; the calyx is short and small, 5-lobed; the corolla is slightly two-lipped, the tube about equal in length to the lips, the upper lip with 4 shallow lobes, the lower lip unlobed, the outside covered with soft hairs or glandular hairs; stamens 5; pistil 1, both extending beyond the corolla when the flower is in full bloom, ovary inferior, hairless. Berry spherical, black and glossy when ripe; seeds numerous, elliptical or triangular-ovate, slightly flattened, black or brown, glossy. Flowering period May-September, fruiting period July-October.
(II) Growth habits
Honeysuckle prefers a warm and humid climate and has strong stress resistance; it is cold-resistant and also resistant to high temperatures, but the optimum temperature for flower bud differentiation is about 15°C, and the optimum temperature for growth is 20-30°C. It is tolerant of waterlogging, drought, and salinity-alkalinity. It prefers ample sunlight; light has a great influence on plant growth and development, and sufficient sunlight can make the plant grow luxuriantly and robustly, thereby increasing flower yield.
Seed germination requires a relatively low temperature; for example, if placed in a refrigerator for 80 days, the germination rate can reach about 80%. Seed viability is 2-3 years.
(III) Cultivation techniques
1. Site selection and land preparation. Honeysuckle has no strict requirements for soil, but deep, loose, and fertile humus soil is best. Before planting, apply 4000 kg of farmyard manure per mu, and plow deeply and harrow finely. For seed propagation, flat beds 1 m wide can be made; for cutting propagation, beds are not necessary.
2. Propagation methods. Cutting propagation is the main method, but seed propagation can also be used.
(1) Cutting propagation. Generally carried out during rainy weather in summer and autumn. Select 1-2-year-old branches with vigorous growth and no pests or diseases, cut them into 30-35 cm long cuttings, and remove the lower leaves. On the selected ground, dig holes at a row spacing of 160 cm and a plant spacing of 150 cm, with a hole depth of 16 cm, and insert 5-6 cuttings per hole, spread apart and placed obliquely in the soil, with 7-10 cm exposed above ground. Insert immediately after cutting, then fill the soil, firm it, and water. The method of raising seedlings by cuttings and then transplanting can also be used, to save cuttings and facilitate management.
(2) Seed propagation. In November, collect ripe fruits, put them in water and rub-wash them, remove the flesh and shriveled seeds completely, take out the plump seeds and dry them. In April of the following year, soak the seeds in warm water at 35-40°C for 24 hours, take them out and mix with 2-3 times their volume of wet sand to promote germination. When 30% of the seeds have cracked open, they can be sown. Water the prepared bed thoroughly, and when the surface soil is slightly loose and dry, level the bed surface, draw shallow furrows at a row spacing of 20 cm, and evenly scatter the seeds into the furrows. Cover with 1 cm of soil, then cover with a layer of grass, and keep it moist regularly. About 10 days after sowing, seedlings can emerge. Transplant in autumn or the following spring; the transplanting method is the same as for cutting propagation, using about 1.5 kg of seeds per mu.
3. Field management
(1) Cultivation, weeding, and hilling. After planting, cultivate and weed in a timely manner, first deep and then shallow, and do not damage the roots. Every year in early spring and after autumn before the ground freezes, hill up the soil to prevent the roots from being exposed.
(2) Topdressing. Often carried out together with hilling. The method is to open a shallow ditch around the flower clump, scatter the fertilizer into the ditch, and cover it firmly with soil. The fertilizer type can be mainly farmyard manure, with a small amount of chemical fertilizer applied as well; the amount of fertilizer can be determined according to the size of the flower clump. Generally, for large perennial flower clumps, 5-6 kg of farmyard manure and 50-100 g of compound fertilizer can be applied per clump. In addition, after picking flowers, topdressing once more can be done if conditions permit.
(3) Pruning and trimming. In the first 2 years after planting, based on the main stem of the original seedling, select and retain 2-4 robust main stems, remove the terminal shoots, cut off other branches, and remove all side buds, repeating this many times to promote thickening and shaping of the main stems, so that the whole plant forms an umbrella shape. After the shape is set, prune every year in winter and summer. Winter pruning mainly follows the principles of "lightly prune vigorous branches, heavily prune weak branches, completely prune dead branches, and prune every branch." Generally, strong branches should retain 8-10 pairs of buds; weak branches should retain 3-5 pairs of buds; and thin, weak, diseased, dead, twining, and high-forking branches should all be cut off completely. Summer pruning should be light. Generally, after the previous crop of flowers is harvested, cut off the terminal shoots of vigorously growing branches to promote the sprouting of new branches, and all small branches that are thin and weak, have yellowing leaves, or affect ventilation and light transmission should be cut off completely. Proper summer pruning has a clear yield-increasing effect on the second and third crops of flowers.
4. Pest and disease control
(1) Brown spot disease. Occurs from June to September, and is especially severe when temperatures are high and humidity is high, damaging the leaves. Control methods: frequently remove diseased branches and fallen leaves; increase the application of phosphorus and potassium fertilizers to improve the plant's disease resistance; in the early stage of the disease, spray with 1:1:200 Bordeaux mixture or 65% zineb wettable powder at 500 times dilution.
(2) Coffee longhorn beetle. Begins to occur in May-June, with larvae boring into and feeding on branches and trunks, especially severely damaging plants more than five years old. Control methods: in April-May, during the adult emergence period and the early larval hatching period, spray with 80% dichlorvos emulsion at 1000 times dilution; use sugar-vinegar liquid (sugar:vinegar:water:trichlorfon = 1:5:4:0.01) to trap and kill adults; in July-August, release the natural enemy Sclerodermus to control it.
(3) Honeysuckle looper. Occurs from June to September, with larvae biting and eating leaves. Control methods: clean the field in winter; when larvae are found, immediately spray with 80% dichlorvos emulsifiable concentrate at 1000 times dilution or 95% crystalline trichlorfon at 800-1000 times dilution.
(IV) Harvesting and processing
Generally, the first crop of flowers is picked in mid-to-late May, and the second crop in mid-to-late June. Harvesting is most suitable when the upper part of the flower bud is swollen but not yet open and is greenish-white. After the flowers are picked, they should be dried in the shade or by heat immediately. Place the flower buds in a drying tray, with a thickness of 3-6 cm as appropriate, and the principle is to dry them on the same day. If rainy weather occurs, dry them by heat in a timely manner. At the beginning of drying, use 30-35°C; after 2 hours, the temperature can be raised to about 40°C; after 5-10 hours, raise the temperature to about 55°C so that the flowers dry quickly. During drying, do not turn them with hands or anything else, otherwise the flowers are likely to turn black. Once drying has started, it must not be stopped before completion, otherwise they will heat up and deteriorate. Honeysuckle stems are obtained by cutting tender branches in autumn and winter and drying them in the sun.