Propagation Methods and Key Cultivation Management Points for Chinese Privet (Ligustrum quihoui)
Recently, many nursery growers and flower growers have asked about the sowing method for Chinese privet (Ligustrum quihoui) and how to prevent and control its diseases. Below, the editor of Huinong Network has summarized all these questions for everyone.
I. Propagation Methods
Propagation is often carried out by sowing, cuttings, and division.
(1) Propagation by sowing
Propagation of Chinese privet by sowing is divided into steps such as seed collection and treatment, nursery land preparation, and sowing.
1. Seed collection and treatment
① Seed collection. Use pruning shears to cut off the fruit clusters and pile them in a cool place. After they rot, remove the flesh to obtain clean seeds.
② Seed treatment. Dry the clean seeds obtained, then put them in cloth bags for dry storage, or directly carry out low-temperature stratification to promote germination. Low-temperature stratification method: spread a 10 cm thick layer of wet river sand on the indoor floor (the humidity of the river sand should be such that it forms a ball when squeezed in the hand and breaks apart when released), layer the seeds and river sand in a ratio of 1:2, with a height not exceeding 30 cm, then spread another 10 cm thick layer of river sand on top to seal it, and insert a few perforated bamboo tubes for ventilation; check the seeds frequently, replace the sand when the river sand is too wet, and spray appropriately with water when it is too dry.
2. Nursery land preparation
Choose a plot of slightly acidic soil that is fertile and convenient for transportation and water supply as the nursery land.
① Nursery land preparation. In late autumn and early winter, deep plow the nursery land once to a depth of 35 cm, without harrowing. Through winter freezing of the soil clods, the physical and chemical properties of the soil can be improved, soil weathering can be promoted, and pests and diseases can be reduced. In winter, taking advantage of the rural winter slack season and abundant labor, dig the drainage ditches around the nursery land (perimeter ditches), with a standard of 40 cm wide and 35 cm deep. In mid-to-late February, apply 2000 kg of fully decomposed barnyard manure per mu, or 200 kg of decomposed cake fertilizer, or 80 kg of potassium sulfate compound fertilizer (15-15-15); all three of the above fertilizers can be applied together with 75-100 kg of superphosphate to promote good seedling growth. After fertilizing, use a harrow machine to harrow continuously 3-4 times, so as to level the nursery land, break up the soil, and evenly mix the fertilizer into the soil.
② Dig ditches and make beds. Mark lines according to a width of 1.5 m to make beds, of which the bed surface width is 1.2 m, the bed ditch width is 0.3 m, and the ditch depth is 0.25 m. To avoid sunlight scorching the seedlings, the seedbeds are mostly oriented north-south, with length controlled within 20 m; if too long, a waist (middle) ditch must be opened so that the perimeter ditch, waist (middle) ditch, and bed ditch are connected, facilitating irrigation and drainage and personnel operations. Spread the soil from the ditches evenly on the bed surface to increase the fertile soil layer.
③ Sterilization and insect killing. To prevent outbreaks of pests and diseases in the nursery land, sterilization and insect killing should be carried out once before sowing. Per mu, 1-1.5 kg of 70% fenaminosulf wettable powder mixed with 10 kg of fine soil can be broadcast to prevent diseases, and 3-5 kg of 3% carbofuran granules per mu can be broadcast directly to prevent insect pests.
3. Sowing
In early March, take out the dry-stored seeds, and sieve out the seeds that underwent low-temperature stratification to promote germination; both need to be carefully selected to remove moldy seeds and obtain clean seeds. Dry-stored seeds: first soak in warm water for 24 hours, changing the clean water once every 12 hours, then soak the seeds in 0.1% potassium permanganate solution for 30 minutes for sterilization; after rinsing and draining, they can be sown. Seeds that underwent low-temperature stratification to promote germination: sow directly after rinsing and draining.
First open drill sowing furrows, with a furrow spacing of 30 cm and a furrow depth of 2 cm; dry-stored seeds and seeds that underwent low-temperature stratification to promote germination need to be drill-sown separately. When sowing, sow the seeds evenly in the furrows at a spacing of 0.5 cm, cover with 2 cm thick fine soil after sowing, water thoroughly with a watering can, and then cover with pine needles, straw, sawdust, etc., to preserve moisture and allow ventilation. After the Chinese privet seedlings emerge, remove the pine needles, straw, and other mulch in batches, and spray with 1000 times dilution of 50% carbendazim wettable powder for sterilization and 2500 times dilution of 2.5% deltamethrin emulsifiable concentrate for insect killing, so as to achieve prevention and control.
Through experiments, Chinese privet seeds that underwent low-temperature stratification to promote germination emerged earlier and more uniformly, superior to dry-stored seeds.
(2) Propagation by cuttings
Chinese privet cuttings can be divided into hardwood cuttings and softwood cuttings.
1. Hardwood cuttings
Hardwood cuttings refer to cuttings made in February to March using one- to two-year-old lignified branches, including nursery land preparation, cutting collection and insertion, and post-insertion management.
① Nursery land preparation. a. Land preparation. The land preparation method is the same as that for propagation by sowing.
b. Dig ditches and make beds. For the cutting nursery land, the bed surface width is 1 m, the bed ditch width is 0.3 m and the depth is 0.25 m, and the length is controlled within 20 m. Further rake and crush the soil on the seedbed into a turtle-back shape that is slightly higher in the middle and slightly lower around the edges, to prevent water accumulation. In spring, set up shade frames according to the cutting area, and cover the shade frame cloth with 50% shade netting; the shade netting must be connected with sturdy rope or wire, and the surroundings of the net should be level with the ground to prevent direct sunlight from reaching the seedbed. The shade frame must be sturdy and able to withstand strong winds.
c. Sterilization and disinfection. 24 hours before cutting, water the seedbed thoroughly with 0.1% potassium permanganate solution.
② Collecting cuttings and inserting them. This can be combined with spring shaping and pruning; cut one- to two-year-old lignified peripheral branches of Chinese privet and place them in a wind-protected, cool place. Collect cuttings, cut them short, and insert them at the same time; in principle, branches collected on the same day should be inserted on the same day. Cut the branches into 12-15 cm lengths with 2-3 buds or leaves, remove the lower leaves, and keep the upper leaves; cut the top flat and the bottom at a slant; tie 50 cuttings into 1 bundle. Quickly dip the base in 0.2% IBA (indolebutyric acid) solution for 5-10 seconds, drain slightly, and then insert; the insertion depth should be more than 2/3 of the cutting length.
③ Post-insertion management. After finishing cuttings in one bed, water thoroughly quickly, then spray with 1000 times dilution of 50% thiophanate-methyl; afterward, maintain suitable soil moisture according to weather conditions, and rooting will occur in about 30 days. During this period, pest and disease management needs to be strengthened; every 10 days or so, pull out rotten cuttings and burn or bury them, and spray the whole field with 1000 times dilution of 50% carbendazim wettable powder for sterilization. Two weeks after complete rooting, the shade netting can be removed.
2. Softwood cuttings
Softwood cuttings refer to cuttings made in May to July or September using semi-lignified branches of the current year. Softwood has the characteristics of abundant vitality, vigorous cell division, and easy rooting.
① Nursery land preparation. Same as the nursery land preparation for hardwood cuttings. Because summer and autumn have strong sunlight and high temperatures, about 90% shade netting must be used; summer has many strong winds and rainstorms, so the shade frame must be built firmly, with wooden stakes driven in around it, and the shade netting fixed with wire.
② Nutrient management of the cutting orchard. Usually, nutrient management of the cutting orchard needs to be strengthened. 10 days before collecting cuttings, spray the leaves once with 0.2%-0.3% potassium dihydrogen phosphate + 1200 times dilution of 68.75% oxadixyl·mancozeb, and spray once more after 5 days. If drought occurs, irrigate once heavily. Chinese privet cutting orchards cultivated in this way produce branches with abundant vitality, strong vitality, and few pests and diseases.
③ Collecting cuttings and inserting them. Cuttings should be collected before sunrise. Place the collected branches indoors and spray water frequently to preserve moisture and prevent dehydration. Indoors, cut the branches into 8-10 cm lengths; when cutting, remove the young tender tip portion, leave 2 leaves, and make bundles of 50. Quickly dip the lower part in 1000 times dilution of ABT rooting powder or IBA (indolebutyric acid), and after it dries slightly, insert the cuttings. Before inserting, use a wooden stick of the same thickness as the cuttings to make holes in the cutting bed, place the cuttings into the holes, and press firmly with the hand. After finishing cuttings in one bed, water thoroughly quickly, and spray with 1000 times dilution of 50% carbendazim wettable powder. Build a cross-shaped frame at each end of the cutting bed, use 2 m long, 2 cm wide bamboo strips in the middle to build a small arched shed, cover fully with 2 m wide medium film, press the surroundings with stones, and then cover with a layer of 50% shade netting close to the film.
④ Post-insertion management. This mainly involves managing the temperature and humidity inside the small arched shed. Within 30 days after cutting, the relative air humidity inside the small arched shed should be maintained above 90%, the soil water content should be about 60% of saturated water content, and the temperature should be controlled below 38°C. To reduce transpiration, leaf spraying can be used to increase relative air humidity. After Chinese privet begins to root, ventilation can be appropriately increased and soil water content reduced. When Chinese privet has completely rooted and 50% have begun to sprout leaves, hardening off is needed: first open one end of the small arched shed, then open the other end after 3-5 days; after another 3-5 days, remove the film and the 50% shade netting on the small arched shed, and after two weeks, remove the 90% shade netting on the shade frame. During this period, every 10 days pull out rotten and dead cuttings and burn or bury them, and spray the whole field with 1000 times dilution of 50% thiophanate-methyl wettable powder for sterilization. In winter or spring, transplant the cutting seedlings to the field.
(3) Propagation by division
In spring, select Chinese privet plants with vigorous growth and many root suckers, cut them apart from the roots for separate planting, and water after planting; they can develop into independent plants.
II. Seedling Stage Management
1. Thinning and filling in seedlings
Thinning of sown seedlings can be carried out twice: the first time, when the seedlings are 5-10 cm tall, combine thinning with filling in gaps; use a small pointed trowel to gently dig up the dense seedlings with native soil and immediately replant them in sparse areas (or find another field for planting); both the original seedling field and the transplanting field should be watered and firmed. The second time is final thinning, about 15 days after the first thinning. Thinning should follow the principle of "thin out small ones and keep large ones, thin out dense ones and keep sparse ones, thin out inferior ones and keep superior ones, and maintain equal spacing."
2. Loosening soil and weeding
Loosening soil and weeding should be carried out when operations are possible after irrigation or rain. The depth of soil loosening should be shallower than the soil covering depth. For the seedbed of sown seedlings, perimeter ditches, waist ditches, and bed ditches, a hoe or shovel can be used to directly loosen and remove soil, making the soil loose and breathable; for weeds in cutting seedling fields, use a small pointed trowel to pick them out little by little, and water and firm the loosened seedlings. From May to July, weed once every half month; from August to September, weed once a month, to reduce competition between weeds and seedlings for light, water, and fertilizer, and promote robust seedling growth.
3. Water and fertilizer management
Reasonable irrigation is the prerequisite for promoting normal growth and development of seedlings. Around the emergence of spring-sown seedlings, according to weather conditions, irrigation should be done little but often, alternating dry and wet; during the plum rain season, attention should be paid to clearing ditches and draining silt; in summer drought, the number of irrigations should be increased, watering enough and thoroughly; in autumn, water less; in winter, do not water. From June to August, topdressing can be combined with watering: for sown seedlings, broadcast 5-10 kg of urea per mu, watering while broadcasting to dissolve and wash it away, so as not to burn the seedlings and cause fertilizer damage; for cutting seedlings, spray leaves with 0.2%-0.3% potassium dihydrogen phosphate aqueous solution; both topdressing methods should be done once every 15 days, with continuous topdressing 2-3 times, which can effectively promote seedling growth. After August 15, stop topdressing urea; a small amount of phosphorus and potassium fertilizer can be applied to promote lignification of seedlings and safe overwintering.
4. Pest and disease control
The main diseases of Chinese privet include anthracnose, leaf spot, and powdery mildew, which can be sprayed with 800 times dilution of 65% zineb wettable powder. Pests include aphids and cutworms, which can be controlled by spraying with 1000 times dilution of 90% trichlorfon crystal or 2500 times dilution of 2.5% deltamethrin emulsifiable concentrate.
III. Cultivation Management
Transplanting Chinese privet is carried out in late winter and early spring. In addition to routine water and fertilizer management and intertillage tending, the main thing is to adopt different management measures according to different cultivation purposes: for example, if cultivating seedlings for hedges, general extensive management is sufficient; if mainly cultivating ball shapes, transplant after raising seedlings, pay attention to pruning the upper part at ordinary times, cultivate horizontally, and prune into full balls; if cultivating a wave shape, prune according to differences in height and position to form an overall wave shape.
The propagation method for planting Chinese privet is very important. If you want to learn more about cultivation techniques related to Chinese privet, please continue to follow our site Huinong Network!
Osmanthus Tree Planting Techniques and Key Cultivation Management Points
Osmanthus is an evergreen shrub or small tree of the genus Osmanthus in the family Oleaceae, also known as rock osmanthus, nine-mile fragrance, golden millet, etc. It is an excellent garden tree species that combines greening, beautification, and fragrance, and is both ornamental and practical. In ancient Chinese poems praising flowers, the number of works praising osmanthus is also quite considerable, and it has been deeply loved by Chinese people since ancient times. Now let us take a look at osmanthus tree planting techniques!
Variety Classification of Osmanthus Trees
1. Four-season osmanthus varieties: Four-season osmanthus is a clumping shrub, with a low tree form, short and dense branches, and a round spherical crown. New leaves are deep red, and mature leaves are green or yellow-green. The leaves are elliptical broad ovate, and the angle between the main vein and lateral veins is very large, close to vertical. Flower buds are usually solitary or 2-3 stacked together, flowering in batches from September each year to March of the following year, with fragrance less rich than silver osmanthus, golden osmanthus, and red osmanthus. Common varieties include large-leaf four-season osmanthus and small-leaf four-season osmanthus. Varieties that bloom in all four seasons include Yueyue Gui, Rixiang Gui, large-leaf Buddha-top bead, and serrated-leaf four-season osmanthus.
2. Red osmanthus variety group: Red osmanthus is dioecious, with a round spherical crown, light gray bark, relatively smooth, and sparse lenticels. Leaves are leathery, long elliptical or elliptical, with a relatively flat leaf surface, revolute leaf margins, entire margins, occasionally sparsely toothed at the apex, broadly cuneate at the base, obtuse-acuminate or shortly pointed at the apex, 8-10 pairs of lateral veins, reticulate veins obvious on both sides, and petioles 8-10 mm long. Flower color is orange-red, the corolla is slightly inward-curved, fragrance is light, and the flowering period is from late September to early October. Varieties include large-flowered red osmanthus, toothed red osmanthus, cinnabar red osmanthus, and broad-leaf red.
3. Golden osmanthus variety group: Golden osmanthus has a round spherical crown, strong tree vigor, upright branches, and is very compact. Bark is gray, lenticels are round or elliptical, and spring shoots are relatively thick. Leaf color is dark green, leaves are elliptical, the leaf surface is uneven, and leaf margins are slightly wavy. Flower color is yellow, with a rich fragrance, does not set fruit, blooms in autumn, and the flowers range from lemon yellow to pale golden yellow. Varieties include large-flowered golden osmanthus, large-leaf yellow, Huangchuan golden osmanthus, late golden osmanthus, round-leaf golden osmanthus, Xianning late osmanthus, ball osmanthus, round-petal golden osmanthus, willow-leaf Su golden osmanthus, Jinshi golden osmanthus, and wave-leaf golden osmanthus.
4. Silver osmanthus variety group: Silver osmanthus has a round spherical crown, spreading large branches, dense branches and leaves, and good growth. Bark is light gray, lenticels are numerous and large, shaped like snowflakes, and very obvious. Leaves are green or dark green, long elliptical or elliptical, relatively broad and thick, and the leaf surface is relatively flat. Flowering occurs in early to mid-September, flower color ranges from creamy yellow to lemon yellow, fragrance is rich, does not set fruit after flowering, and it blooms in autumn. Varieties include broad-leaf seed silver osmanthus, willow-leaf silver osmanthus, hard-leaf silver osmanthus, seed silver osmanthus, Jiulong osmanthus, early silver osmanthus, late silver osmanthus, Baijie, pure white silver osmanthus, and Qingshan silver osmanthus.
Growing Environment for Osmanthus Trees
1. Temperature: Osmanthus trees like warmth. The average temperature in growing areas is 14-28°C, the average July temperature is 24-28°C, the average January temperature is above 0°C, and it can tolerate a minimum temperature of -13°C. The most suitable growing temperature is 15-28°C. In areas south of the Qinling Mountains and Huaihe River in China, it can overwinter outdoors. It is not very cold-resistant, but compared with other evergreen broadleaf tree species, it is still a relatively cold-resistant tree species.
2. Moisture: Osmanthus trees like moisture. Humidity is extremely important for the growth and development of osmanthus, requiring an annual average humidity of 75-85% and annual precipitation of about 1000 mm. Especially in the young stage and when adult trees bloom, more water is needed. If drought occurs, flowering will be affected. Water accumulation must be avoided, but it also has a certain drought tolerance.
3. Light: Osmanthus prefers sunlight and can also tolerate shade. Under full sunlight, its branches and leaves grow luxuriantly and flowering is dense; in shaded places, branches and leaves are sparse and flowers are few. If potted indoors in the north, special attention must be paid to sufficient light to facilitate growth and flower bud formation. Strong sunlight and shade are both unfavorable to its growth; generally, 6-8 hours of light per day is required.
4. Soil: Osmanthus is not very demanding about soil. Except for alkaline soil, low-lying land, or overly clayey and poorly drained soil, it can generally grow, but deep, loose, fertile, well-drained slightly acidic sandy loam is most suitable.
5. Air: Osmanthus has a certain resistance to harmful gases such as chlorine, sulfur dioxide, and hydrogen fluoride, and also has a strong ability to absorb and retain dust. It is suitable for planting in ventilated and light-transmitting places. It likes a clean and ventilated environment and is not tolerant to smoke and dust damage; after being harmed, it often fails to bloom.
Osmanthus Tree Propagation Techniques
1. Sowing: Osmanthus fruit usually matures in April to May, and can be harvested when the peel changes from green to purplish black. Osmanthus seeds have after-ripening; they need at least half a year of sand storage. After harvesting, sprinkle water and pile for fermentation, remove the flesh, place in a cool place to let the seeds dry naturally, and store mixed with sand. After sand storage, they can be sown in autumn or spring. Before sowing, prepare the land well and apply sufficient base fertilizer; they can also be sown in indoor seedbeds. When sowing, place the seed hilum sideways to avoid bending of the radicle and young stem, which would affect seedling growth in the future.
2. Grafting: Osmanthus grafting rootstocks are mostly privet, Chinese privet, small wax, water wax, etc.; when mass-propagating seedlings, Chinese privet is mostly used. Before spring germination, cut off the rootstock 5 cm above the ground, cut 10-12 cm long vigorous 1-2 year old osmanthus branches, cut one side of the base into a 2-3 cm cut surface, cut the opposite side into a small 45-degree bevel, make a vertical cut about 2-3 cm deep at about 1/3 of one side of the rootstock, insert the scion into the cut so that the cambium layers align, tie tightly with plastic bags, and then bury in soil for cultivation.
3. Cuttings: Osmanthus cuttings are usually made before spring germination using fully developed one-year-old branches, cut into 5-10 cm lengths, remove the lower leaves, leave 2-3 green leaves on the upper part, and insert into river sand or loess seedbeds at a plant-row spacing of 3*20 cm. After insertion, irrigate or spray water promptly, and shade, maintaining a temperature of 20-25°C and relative humidity of 85-90%. After 2 months, they can root and be transplanted.
4. Layering: Osmanthus can be divided into low layering and air layering. The low layering method is to select 1-2 year old branches on the lower part of a relatively thick low-trunk mother tree from spring to early summer, choose a part easy to bend, use a sharp knife to cut or girdle it, press it into a 3-5 cm deep furrow, and fix the pressed branch with a wooden stick. The air layering method is to select 1-2 year old thick branches from the mother tree in spring, cut a ring or girdle in the same way as low layering, then smear the wound with culture medium, tie plastic bags tightly above and below, and after rooting in autumn, cut them off from the mother plant for maintenance.
Osmanthus Tree Planting Techniques
1. Digging holes: Before lifting osmanthus tree seedlings, dig the planting holes first. The diameter of the holes should be 0.5-0.6 m larger than the soil ball carried by the seedling roots, so that when planting, the soil around the soil ball can be tamped, making the soil ball closely combine with the hole soil. The depth of the holes should be 0.2-0.3 m larger than the soil ball carried by the seedling. When digging holes, place topsoil and subsoil separately, so that when filling soil, topsoil is filled first and then subsoil. After digging the holes, it is best to apply base fertilizer. Above the base fertilizer, fill in about 10 cm of soil so that the base fertilizer does not directly contact the soil ball, preventing root burn.
2. Planting: When planting an osmanthus tree, place the seedling in the previously dug planting hole, cut off the grass rope tied around the crown, adjust the ornamental side, make the tree upright, and fill in a small amount of topsoil to fix the soil ball. Then cut the binding material and fill in topsoil. When filling to half, use a thick wooden stick to tamp the soil around the soil ball. Then continue filling in subsoil; covering soil 0.1-0.2 m higher than the original soil ball is appropriate. If the plant is relatively tall, wooden stakes are needed to support and fix it when planting. After the seedling is planted, build a soil berm around it and water thoroughly promptly, until water no longer seeps down.
Osmanthus Tree Planting Management
1. Fertilizer and water: After transplanting osmanthus trees, if heavy rain causes water accumulation in the nursery land, dig ditches to drain water; in drought, water to resist drought. In addition to applying sufficient base fertilizer, apply fertilizer 3 times each year: in late March, apply 0.1-0.3 kg of quick-acting nitrogen fertilizer per plant to promote height growth and more young shoots; in July, apply 0.1-0.3 kg of quick-acting phosphorus and potassium fertilizer per plant to improve drought resistance; in October, apply 2-3 kg of organic fertilizer (such as farmyard manure) per plant to improve cold resistance and prepare for overwintering.
2. Pruning: Osmanthus has strong sprouting ability and the characteristic of naturally forming thickets. It flushes shoots twice each year in spring and autumn. If not pruned and buds not removed in time, it is difficult to cultivate tall plants, and it easily forms a phenomenon of dense upper branches and sparse lower branches, strong at the top and weak at the bottom. When pruning, except for shortening when tree vigor and branch vigor are poor, generally thinning branches is the main method; only appropriately thin out overly dense peripheral branches, and cut off water sprouts and diseased and pest-infested branches, to improve ventilation and light transmission conditions for the plant. Remove sprouting branches from the base of the trunk in time, so as not to consume nutrients within the tree and disrupt the tree shape.
3. Loosening soil: In spring and autumn, osmanthus trees are intertilled once each in combination with fertilization, to improve soil structure. Before overwintering, bank soil around the base once and whitewash the trunk once, which can enhance cold resistance. Weed 2-3 times each year, so as to prevent weeds from competing with seedlings for water, fertilizer, and light.
4. Diseases: Common diseases of osmanthus include leaf spot, sooty mold, algal leaf spot, root rot, and iron deficiency. Prevention and control should be carried out according to the disease situation. Leaf spot, sooty mold, and algal leaf spot can be controlled by spraying 0.5 Bordeaux mixture or 500-1000 times dilution of 5% carbendazim. For root rot, attention should be paid to keeping the soil loose and breathable, and avoiding water accumulation. If root rot is caused by fungi, the root can be irrigated with 200-300 times dilution of amobam.
5. Pests: Common pests of osmanthus include sawflies, whiteflies, mites, white peach scale, and yellow stinging caterpillars. Sawflies, whiteflies, and mites can be killed by spraying 1500-3000 times dilution of 100% dimethoate. For white peach scale, besides manual brushing off, in the first and second instar nymph stages, it can be killed by spraying 1000 times dilution of 400% omethoate or 500 times dilution of 40% fenitrothion.
Osmanthus Tree Transplanting Techniques
1. Time: When transplanting large osmanthus trees, the choice of season is very important. Generally (under normal circumstances), the semi-dormant period of healthy trees can be chosen. For example, in Jiangnan, it can be carried out after the Mid-Autumn Festival to the end of the following winter (from mid-September to around February 15 of the following year, except in freezing snowy weather), because this is its semi-dormant stage and new buds have not yet sprouted, which is beneficial to the coordination of various factors within the tree. It can also be chosen during the plum rain season in Jiangnan, because at this time the tree body's first growth peak has ended and its internal nutrients have been replenished, so the survival rate is relatively high.
2. Tree selection: For transplanting osmanthus trees, choose osmanthus trees with full tree shape, luxuriant branches and leaves, no pests or diseases, and easy to dig up and hoist for transport.
3. Digging pits: About one week before transplanting, dig the tree pits at the new planting site. The pre-dug tree pit diameter should be about 1 m larger than the packaging diameter of the transplanted tree, and the height should be level with the height of the transplant packaging. Place the excavated surface soil and lower soil separately, spread the soil out to dry, and at the same time clean out impurities such as bricks and tiles from the soil. Then mix in ferrous sulfate at a ratio of 10:1 (soil being 10 parts), which increases soil acidity, disinfects the soil, and also enhances fertility.
4. Pruning: Pruning osmanthus is one of the keys to transplant survival. Because osmanthus has weak sprouting ability, trunk cutting and branch cutting are not advisable. Only the leaves of osmanthus can be pruned. Use scissors to cut off the leaves, leave the petioles, protect the axillary buds, and retain one third of the original number of leaves. This can reduce water evaporation and also retain the beauty of the original crown.
5. Lifting seedlings: For transplanting osmanthus, hard packaging is best. Water the osmanthus tree to be transplanted thoroughly one week in advance, so that its root system absorbs enough water; this makes it easy to dig into a ball and prevents the soil ball from breaking apart due to overly dry soil. The diameter of the soil ball should be 6 to 8 times the diameter of the crown at 1 m above ground of the plant, and the height should be 70% of the soil ball diameter. If conditions permit, digging larger is better.
6. Planting: Before planting, backfill the pre-dug tree pit with 10-15 cm of original soil brought back with the transported osmanthus tree. Because osmanthus trees are not tolerant to flooding, the planting depth of osmanthus should be 10-15 cm higher than the original ground level. First lower the osmanthus tree and place it according to its original growth orientation, then place one plastic pipe in each of the four corners of the tree pit to increase root breathability after the tree pit is filled with soil. Then, while removing the template in order, backfill soil to 1/3 of the soil ball height, fill original soil closely around the soil ball, filling one layer and tamping one layer to prevent the soil ball from breaking. After the tree pit is completely filled and tamped, build a berm, install supports, and water thoroughly for the first time.
7. Management: First, water thoroughly again 3 to 4 days after the first watering. Second, after the water has completely dried, surround the remaining soil around the tree roots to form a mound higher in the middle and lower around the edges, so that the osmanthus tree will not be drowned by water accumulation. Third, in the following spring, be sure to water once with spring water. Fourth, at an average temperature of about 20°C, spray the leaves and branches once every half month with a mixture of potassium dihydrogen phosphate and fungicide (carbendazim, etc.). This both applies foliar topdressing to the osmanthus tree and also plays a sterilizing role.
Osmanthus Tree Planting Methods and Cultivation Management Techniques
Osmanthus is an evergreen tree of the genus Osmanthus in the family Oleaceae, also called muxi rock osmanthus, golden millet, nine-mile fragrance, etc. It has a cultivation history of more than 2500 years in China and is one of China's ten traditional famous flowers, and also one of the most precious flowering trees in modern urban greening. It originated in southwest and south-central China, and is now widely cultivated in all provinces and regions of the Yangtze River basin; in North China and Northeast China, it is mostly potted. It has a beautiful tree posture, luxuriant branches and leaves, verdant green leaves, and is evergreen all year round. It is especially attractive for its faint, secluded floral fragrance, truly "dominating the three autumns and pressing down all fragrances." It has been designated as the city flower by world-famous tourist cities such as Suzhou, Hangzhou, and Guilin.
Overview of Osmanthus Cultivation
1. Osmanthus varieties: There are many varieties of osmanthus, mainly including golden osmanthus, silver osmanthus, red osmanthus, and four-season osmanthus. Golden osmanthus has a tall trunk, a round full crown, large dark green glossy elliptical leaves, wavy leaf margins, thick leaves, golden yellow flowers, and the strongest fragrance; silver osmanthus has smaller elliptical, ovate, or obovate leaves, relatively thin, with yellow-white or pale yellow flowers, fragrance slightly lighter than golden osmanthus, and the flowering period is also 1 week later than golden osmanthus; red osmanthus has smaller lanceolate or elliptical leaves, pointed apex, rough leaf surface, orange-yellow or orange-red flowers, and relatively light fragrance; four-season osmanthus has elliptical, relatively thin leaves, yellow or pale yellow flowers, a long flowering period, blooming several times except in severe cold and heat, but mostly in autumn, with light fragrance and smaller leaves, mostly shrub-like.
2. Osmanthus habits: Osmanthus likes a warm and humid climate and has a certain cold resistance, but is not tolerant to severe cold. It likes light and also tolerates shade; when young, it needs a certain degree of shading. It does not have high soil requirements, and likes slightly acidic soil with high, dry terrain and rich humus, especially deep, fertile, moist, well-drained sandy soil. It is not tolerant to arid and barren soil, and avoids saline-alkali soil and waterlogged land. Planting it in overly wet land with poor drainage will cause poor growth, root rot, leaf drop, and ultimately death of the whole plant.
3. Osmanthus cultivation value: Osmanthus has relatively wide applications. It is often planted in gardens, along roadsides, on lawns, and in courtyards, and is the best greening tree species for government offices, schools, the military, enterprises and institutions, streets, and homes. Because it has a certain resistance to harmful gases such as sulfur dioxide and hydrogen fluoride, it is also an excellent flowering tree for greening industrial and mining areas. When paired with mountains, stones, pavilions, terraces, buildings, and chambers, it appears even more dignified, elegant, pleasing to the eye, and delightful. It is also an excellent material for potted plants; after being made into bonsai, it can be viewed for shape, stone flowers, and fragrance, truly "three benefits in one." In addition, osmanthus wood is hard, glossy, and beautifully grained, and is a good material for carving. Osmanthus is an important raw material for making osmanthus sugar, osmanthus tea, osmanthus wine, and osmanthus cake. The essence extracted from osmanthus is widely used in the food industry and chemical industry. Cinnamon bark can extract dyes and tanning materials, and osmanthus leaves can be used as seasoning. They add a fresh fragrance to food.
Osmanthus Propagation Methods
1. Cuttings and grafting: Osmanthus propagation methods include sowing, cuttings, grafting, and layering. In production, cutting and grafting propagation are the most common. Cutting propagation has simple technology, large propagation quantity, fast speed, high survival rate, and low cost, and is the most widely adopted and most commonly used propagation method by nursery producers and flower lovers.
① Cutting time: From early March to mid-April, select 1-year-old spring shoots for cuttings; this is the best cutting time. It is also possible to select semi-mature branches of the current year from late June to late August for heel cuttings, but this has high requirements for temperature and humidity control.
② Cutting collection and treatment: From young and middle-aged trees, select robust, full, pest-free branches from the upper middle and periphery of the tree as cuttings. Cut the branches into 10-12 cm lengths, remove the lower leaves, and keep only 3-4 upper leaves. If conditions permit, soak the cuttings in 50-100 ppm GGR6 solution for 0.5-1 hour, which is very beneficial for rooting of the cuttings.
③ Cutting medium preparation: Use slightly acidic, loose, breathable soil with good water retention as the cutting substrate. Before cutting, disinfect and sterilize the cutting medium with carbendazim, quintozene, and other chemicals.
④ Post-insertion management: This mainly involves controlling temperature and humidity, which is the key to whether the cuttings can root and survive. The best rooting soil temperature is 25-28°C, and the best relative humidity should be maintained above 85%. Methods such as shading, plastic arched sheds, sprinkling water, and ventilation can be used for control. Second, attention should be paid to preventing mold, because high temperature and high humidity easily breed mold; spray alternately with carbendazim and thiophanate-methyl weekly for sterilization. Grafting propagation has the advantages of fast seedling formation, vigorous growth, early flowering, and small variation, and is also one of the more commonly used methods.
⑤ Rootstock cultivation: Mostly 1-2 year old seedlings such as privet, Chinese privet, and small-leaf ash are used as rootstocks. Among them, using privet to graft osmanthus has a high survival rate and fast initial growth, but the wound heals poorly, and it is prone to breaking off when exposed to strong winds or external collision.
2. Grafting propagation: Grafting is carried out around Qingming Festival. The two most commonly used methods in production are the cleft grafting method and the side grafting method. It is advisable to select fully lignified, robust, disease-free 1-2 year old branches from adult trees as scions, remove the leaves, and retain the petioles. For the cleft grafting method, before spring seedling germination, cut the rootstock off 4-6 cm above the ground before grafting. The thickness of the scion should match the thickness of the rootstock, and the cut surface of the scion should be smooth. The key to successful cleft grafting lies in aligning the cambium layers of the rootstock and scion and tying tightly. For the side grafting method, there is no need to cut off the rootstock; directly insert the scion bud into the rootstock, and cut off the rootstock after successful grafting. No matter which grafting method is used, collect scions and graft as much as possible at the same time. For scions obtained from other places, be sure to maintain their freshness. Grafting is best done on sunny, windless days. After grafting, check the survival rate, and do good work in supplementary grafting, bud removal, rootstock cutting, removing binding strips, water and fertilizer management, and pest and disease control.
3. Propagation by sowing: Osmanthus can also be propagated by sowing. However, because some varieties do not set fruit or set few fruits, and because seedlings raised by sowing take a long time to flower, requiring more than 10 years to bloom, with large variation, nursery producers and home flower lovers rarely use this method. Osmanthus seeds mature around May. After seed collection, sowing can be carried out in two periods: first, sowing immediately after collection, which can reduce the step of seed storage, and by autumn some seeds will germinate and emerge. Its disadvantage is that seedling overwintering management is difficult and they are prone to freezing damage. Second, after seed collection, first store in sand, then select the seeds from the sand and sow in the following spring. They germinate and emerge in April. The advantages of this method are: seedlings grow fast and seedling management is less difficult. When using sowing to raise seedlings, pay attention during the seedling stage to preventing and controlling seedling damping-off, strengthening water and fertilizer management, thinning and filling in seedlings in time, intertilling and weeding, and doing good work in shading, cooling, and cold and freezing protection.
4. Propagation by layering: Layering time should be selected before buds sprout in spring. Because osmanthus branches are not easy to bend, ground layering is generally not used; only air layering is used. When using the air layering method, select 2-3 year old branches with strong growth vigor on a superior mother plant, girdle a 0.3 cm wide ring of bark on the branch, then apply 100 ppm GGR6 solution or the same dose of naphthalene acetic acid to the girdled area, then use plastic film to hold mountain soil, leaf mold, moss, etc., wrap the wounded part, water thoroughly, and tie the bag opening firmly. Observe frequently and replenish water in time so that the wrapping material is always in a moist state. After cultivation through summer and autumn, new roots will grow. In the following spring, cut the rooted branches off from the mother plant, open the wrapping material, transplant with soil into pots, water thoroughly, and place in a cool place for maintenance. After a large number of new shoots sprout, expose them to full sunlight.
Cultivation Management
One-year-old osmanthus seedlings raised through sowing, cuttings, and other means are not suitable for immediate use as greening seedlings because of poor resistance to drought, cold, and barrenness. They should first be transplanted into nursery land and continue to be cultivated for 2-5 years, and after they grow into medium seedlings, transplanted again. The key points of cultivation management are briefly introduced below:
1. Land preparation: Choose slightly acidic (pH 5.0-6.5) sandy loam with sufficient light, deep soil layers, rich humus, strong permeability, and convenient drainage and irrigation as the cultivation nursery land. In the autumn and winter of the year before transplanting, first fully reclaim the nursery land once, and dig holes according to a plant-row spacing of 1 m x 1.5 m (after 2 years, when they grow thicker and taller, remove every other plant so that the row-plant spacing becomes 2 m x 1.5 m), with planting holes of 0.4 m x 0.4 m x 0.4 m. Apply 2-3 kg of decomposed mild farmyard manure (pig manure, cow dung) and 0.5 kg of phosphate fertilizer per hole as base fertilizer. Mix the base fertilizer evenly with surface loam and fill it into the holes. After the fertilizer is eroded and fermented by winter snow and spring rain, it is easily absorbed by the seedlings.
2. Transplanting: Transplanting is best when the sap has not yet flowed or has just begun to flow, generally from early February to early March. When lifting seedlings, keep as many roots as possible and damage as few roots as possible. After lifting, plant as soon as possible. If seedlings need to be transferred from other places, pay attention to moisture preservation to prevent dehydration. After planting, tamp the soil and water thoroughly once, so that the seedling roots closely contact the soil.
3. Water and fertilizer management: After transplanting, if heavy rain causes water accumulation in the nursery land, dig ditches to drain water. In drought, water to resist drought. In addition to applying sufficient base fertilizer, apply fertilizer 3 times each year: in late March, apply 0.1-0.3 kg of quick-acting nitrogen fertilizer per plant to promote height growth and more young shoots; in July, apply 0.1-0.3 kg of quick-acting phosphorus and potassium fertilizer per plant to improve drought resistance; in October, apply 2-3 kg of organic fertilizer (such as farmyard manure) per plant to improve cold resistance and prepare for overwintering.
4. Pruning and shaping: Osmanthus has strong sprouting ability and the characteristic of naturally forming thickets. It flushes shoots twice each year in spring and autumn. If not pruned and buds not removed in time, it is difficult to cultivate tall plants, and it easily forms a phenomenon of dense upper branches and sparse lower branches, strong at the top and weak at the bottom. When pruning, except for shortening when tree vigor and branch vigor are poor, generally thinning branches is the main method; only appropriately thin out overly dense peripheral branches, and cut off water sprouts and diseased and pest-infested branches, to improve ventilation and light transmission conditions for the plant. Remove sprouting branches from the base of the trunk in time, so as not to consume nutrients within the tree and disrupt the tree shape.
5. Loosening soil and weeding: In spring and autumn, intertill once each in combination with fertilization, to improve soil structure. Before overwintering, bank soil around the base once and whitewash the trunk once, which can enhance cold resistance. Weed 2-3 times each year, so as to prevent weeds from competing with seedlings for water, fertilizer, and light.
6. Pest and disease control: Osmanthus has relatively few pests and diseases, mainly including anthracnose, leaf spot, red spider, and oystershell scale, which can be controlled with Bordeaux mixture, lime sulfur mixture, thiram, thiophanate-methyl, dichlorvos, dicofol, and other chemicals.
Key Points for Transplanting Large Osmanthus Trees
1. Transplanting time: Mid-January to early February is best. At this time the tree is in a dormant state, and not long after transplanting, its activity becomes stronger, making survival easy. Avoid transplanting in summer.
2. Branch cutting: This serves to reduce nutrient consumption within the tree and water transpiration. The amount of branch cutting is determined by tree age and growth vigor. Old trees over a hundred years old should have few or no branches left because of weak growth vigor. Those with strong growth vigor and young trees can appropriately retain more branches. When cutting branches, first remove diseased and pest-infested branches, water sprouts, and crossing branches. Afterward, apply petroleum jelly or Bordeaux mixture to the wounds to avoid pest and disease damage and rain erosion.
3. Root cutting: To improve the survival rate of transplanting large osmanthus trees, cut 1/2 of the roots in spring 1-2 years before transplanting, with the cutting point at a distance from the trunk of 2-3 times the trunk diameter, then apply 50-100 ppm GGR6 solution or 0.1% indoleacetic acid solution to the cut roots, cover with soil and water thoroughly, and let them grow new roots.
4. Lifting the trunk: The determined size of the excavated soil ball is generally 4-6 times the ground diameter of the trunk. If it is truly difficult to transport because the ground diameter is too thick, it must not be less than 3 times. While digging, wrap the soil ball with wet straw curtains and grass ropes to prevent it from loosening. Saw off large roots of the tree with a saw, and apply GGR6 and other rooting powders to the cut surfaces. After digging, wrap and tie firmly with wet straw curtains and grass ropes, with the grass ropes tied up to 2.5 m high on the trunk.
5. Transportation: During transportation, load, place, and unload gently. When loading, fix the large tree well and separate it with cushioning material to prevent the tree from colliding, so as not to injure the bark or break the soil ball. Pay attention to moisture preservation on the way.
6. Planting: One month before planting, dig the planting holes first, with a specification 1.5-2 times the soil ball, then fill the holes with mycorrhizal soil and mix in 5-10 kg of decomposed mild farmyard manure and 2 kg of quick-acting phosphate fertilizer, and irrigate for later use. When planting, use a crane to lower the large tree gently into the planting hole, use scissors to cut open the packaging straw curtains and grass ropes, then backfill with barn soil, tread firmly, and water thoroughly.
7. Care and management
① Install fixed supports: Set up tripods around the main trunk of the large tree to prevent the large tree from shaking due to collision by people and livestock or strong winds.
② Set up shade frames: After April, set up shade frames on three sides of the large tree (except the northwest side) to prevent direct sunlight from scorching the bark and to reduce water transpiration. They can be removed when the weather turns cool in October.
③ Watering: Newly planted large trees have damaged root systems and weak water absorption, so the amount of watering should not be too much, lest the roots become moldy and rot. But it also should not be too little, otherwise the tree body will lose water and die.
④ Infusion: Infusion can meet the tree body's demand for water and nutrients and can greatly improve the transplant survival rate. Infusion is generally carried out from April to September. Before infusion, first drill 3-5 infusion holes at the base of the large tree from top to bottom at a 45-degree angle, deep to the pith. Then prepare the medicinal solution, made by dissolving 0.1 g of ABT6 rooting powder and 0.5 g of potassium dihydrogen phosphate per liter of water. Hang the bottle containing the medicinal solution at a high place, insert the trunk syringe into the infusion hole, open the infusion switch, and the liquid can be input into the tree body. After the medicinal solution is infused, pull out the needle and plug the infusion hole with a cotton ball. When infusion is needed next time, take out the cotton ball and infusion can proceed. The number of infusions and the interval time depend on the degree of drought, temperature, and the plant's water demand. After the plant has completely passed the dangerous period, seal the infusion holes well with Bordeaux mixture.