Key points of high-yield cultivation techniques for propagating honeysuckle (Japanese honeysuckle) by cuttings

The flower buds, flowers and leaves of honeysuckle can all be used as medicine, to clear heat and reduce inflammation; the vine is used as medicine to treat rheumatic bone pain; the flowers can be used to extract aromatic oil and to make honeysuckle distillate; it is also a tree species for landscaping and garden cultivation and ornamental viewing.

1. Honeysuckle cutting propagation. Honeysuckle can be propagated by seed, and can also be propagated by cuttings and root division, but seed propagation grows slowly and returns late, and the propagation coefficient of root division is low, so at present all production uses cutting propagation, which has abundant propagation material, a high survival rate and a quick return.

The specific methods are further divided into two types: direct cutting and nursery cutting. For direct cutting, mountain areas use the large-haired flower variety, which has a well-developed root system and strong shoot sprouting ability; in the rainy seasons of summer and autumn, select robust, pest- and disease-free 1-2 year old branches, cut them into 30-35 cm lengths, remove the lower leaves to make cuttings, and insert them as they are cut, directly into vacant land such as mountain slope terraces and field embankments, digging holes 25-30 cm in diameter at a plant-to-plant spacing of 1.3-1.7 m, with a hole depth of 16-18 cm; insert 4-6 cuttings per hole, spread them apart and insert them obliquely in the hole, leaving 5-10 cm exposed above ground, then fill with soil and press firm; in case of drought, water appropriately to increase the survival rate. In order to save branches and make management easier, nursery cutting is also often used; the method is to select a plot with convenient watering, deep plow and level it, apply an appropriate amount of farmyard manure as base fertilizer, in July-August open trenches at a row spacing of 23-26 cm, about 16 cm deep, place the cuttings obliquely upright in the trench at a plant spacing of 2 cm, then fill with soil, cover level and press firm. After planting, water; afterward, if the weather is dry, water once every 2-3 days to keep the soil moist; after about half a month they can take root and sprout, and in the second year they are transplanted in spring or autumn.

2. Shaping and pruning honeysuckle is an important measure to increase yield. Naturally growing honeysuckle has very long branches and must be given support or shaped and pruned; if left untended, the branches creep on the ground and overlap and twine around each other, so flowering is sparse and yield is very low; therefore, installing supports and shaping and pruning are the key to increasing honeysuckle yield.

Pruning in particular has a very significant effect on increasing honeysuckle yield. According to a 1983 trial in Pingyi County, Shandong, after one winter pruning and 3 growing-season prunings, the average total fresh flower yield per clump was 969 grams, while the unpruned average yield was 685 grams; pruning increased fresh flowers by 284 grams per clump compared with no pruning, an increase of 42%. After pruning, the light energy utilization rate of each part of the flower clump is improved, ineffective branches and leaves such as weak branches and water sprouts are removed, the consumption of nutrients and water is reduced, the branches and leaves are arranged most rationally, the growth environment is improved, the plants are robust, and this is conducive to high honeysuckle yield. The specific method is: for honeysuckle cultivated for one or two years, before the branches sprout in spring, cut off the upper part, leaving only about 33 cm as the trunk; after several consecutive years of pruning, the trunk becomes thick and strong and can stand upright as a clump; the lateral branches at all levels on the trunk form an umbrella-shaped round crown, which not only ventilates and lets in light, increases the number of flowers, but also makes it easier to pick the flower buds. Honeysuckle has a very strong natural renewal ability and many new branches; branches that have already flowered may continue to grow in the same year but will not flower again; only new shoots sprouting from the original flowering mother plant can produce flower buds again. Honeysuckle pruning must be determined specifically according to variety, clump age and branch type. According to experience in the Linyi area of Shandong, for the creeping large-haired flower with a crown width of 120-140 cm and long branches on old flower clumps, heavy pruning is required: cut long branches, thin out short branches, with equal emphasis on cutting and thinning. For strong flower clumps, light pruning is mainly used, thinning little and leaving much; for young flower clumps, cutting is mainly used to promote branching and accelerate crown expansion. For the three-dimensional chicken-claw flower, the trunk is obvious, the branches mostly do not touch the ground, and the crown width is 80-120 cm; pruning should remove the top, clear the base cluster, open the inner canopy, and prune overlong branches, diseased and weak branches, dead branches and downward-extending branches, so that the branches stand upright in clumps, the trunk is thick and strong, the branches are evenly spaced, and the flower clump becomes umbrella-shaped with good ventilation and light transmission; in this way there are many new branches and many flower buds. As for pruning time, first is winter pruning, which can be carried out from December to late February of the following year. Second is growing-season pruning, which is carried out after each flower harvest, with the aim of promoting the formation of multiple flushes of flowers and increasing yield. After the first flush of flowers, the first pruning of spring shoots is carried out in early June; the second is in late July after the second flush of flowers, pruning summer shoots; the third is in early September after the third flush of flowers, pruning autumn shoots. Growing-season pruning should mainly be light pruning.

3. Common stem-boring pests of honeysuckle and their control. 1. Coffee tiger longhorn beetle. In the old honeysuckle production areas of Pingyi and Fei County in Shandong, the damage rate of flower clumps over ten years old reaches 80%; after damage, vigor declines, and if damaged for several consecutive years, the entire plant dies.

In Shandong it has one generation a year. Newly hatched larvae first feed on the surface of the xylem; when the larvae reach 3 mm they bore longitudinally into the xylem, forming winding galleries; the bore holes are filled with wood fragments and insect frass, very hard, and there are no frass expulsion holes on the surface of the branches, so it is difficult to detect, and at this time chemical control is also ineffective. Control methods: ① In April-May, during the adult occurrence period and the early larval hatching period, spray 80% dichlorvos emulsifiable concentrate at 1000 times dilution to control adults and newly hatched larvae, which has a certain effect. ② In July-August, on sunny days when the temperature is above 25°C, release the longhorn beetle parasitoid wasp Sclerodermus in the field, which has a good control effect.

2. Leopard moth. In Shandong it has one generation a year. After the larvae hatch, they bore in from the branch fork or new shoot; after 3-5 days the damaged new shoot withers; after the larvae grow to 3-5 mm they expel frass from the entry hole, making them easy to find, and they have the habit of moving to other plants to cause damage.

The larvae gnaw a ring between the xylem and phloem, making the branch easy to break in wind; on one side of the damaged branch there are often several frass expulsion holes, and the frass is long cylindrical and pale yellow; in September-October dead branches appear on the flower clump. Control methods: ① Clean up the flower clumps in time; after harvesting the second flush of flowers, be sure to prune in late July to early August and cut off infested branches; if pruning is too late and the larvae have bored into the lower thick branches, cutting branches again will affect the growth vigor of the flower clump. ② Mid- to late July is the peak hatching period of the larvae and the suitable period for chemical control; use 40% omethoate emulsifiable concentrate at 1500 times dilution, adding 0.3%-0.5% kerosene to promote penetration of the solution into the branches, which can achieve a good control effect.

3. Willow carpenter moth. In the main production areas of Shandong it has one generation every two years, spanning three years.

After hatching, the larvae first live in groups under the old bark of honeysuckle and cause damage; after growing to 10-15 mm they gradually disperse, and often several bore from the middle-lower part of the main stem and the root crown into the phloem and shallow xylem to cause damage, forming broad galleries and expelling large amounts of frass and wood fragments, seriously destroying the physiological functions of the plant, hindering the transport of nutrients and water in the plant, and causing honeysuckle leaves to turn yellow and fall, with flower branches drying up in August-September. Control methods: ① Strengthen field management. Willow carpenter moth larvae prefer to damage weak flower clumps, and most larvae bore in through old holes. Therefore, strengthen tending and management, apply fertilizer and water at the right time, and promote robust growth of honeysuckle to improve insect resistance. ② Chemical control: in July, the peak larval hatching period, use 40% omethoate at 1000 times plus 0.5% kerosene and spray on the branches, or use 40% omethoate or fenitrothion mixed with water at a pesticide-to-water ratio of 1:1 to make a medicinal solution and pour it at the roots; that is, first dig a hole around the flower clump 10-15 cm deep, pour about 20 ml per clump, adjusting appropriately according to the size of the flower clump, then cover with soil and press firm. Because the medicinal solution concentration is high, pay attention to safety when using it.