How to plant Magnolia denudata? Planting methods and cultivation management key points
Magnolia denudata, also known as yulan magnolia, spring-welcoming flower, and yulan flower, is the white-flowered variety among magnolias. It is a deciduous tree of the genus Magnolia in the family Magnoliaceae, native to central China. It is now cultivated in Beijing and areas south of the Yellow River basin. The flowers are white, large, and fragrant, opening before the leaves, with a flowering period of about 10 days. It has very high ornamental value. Let us take a look at the cultivation methods of Magnolia denudata!
Growth habits of Magnolia denudata
Magnolia denudata is native to Java, Indonesia, and is now widely planted in Southeast Asia. It is extensively cultivated in Fujian, Guangdong, Guangxi, Yunnan and other provinces and regions of China. Wild specimens still exist in places such as Lushan, Huangshan, Emeishan, and Jushishan. It is suitable for growing in warm and humid climates and fertile, loose soil. It likes light, is not tolerant of drought, and is not tolerant of waterlogging either. If the roots are submerged for 2-3 days, they will die. It is relatively sensitive to toxic gases such as sulfur dioxide and chlorine, and has poor resistance.
Propagation methods of Magnolia denudata
1. Seed propagation
① Seed collection: Usually in early to mid-September, when the fruits turn red and some split open to reveal red seeds, they can be harvested. After threshing, select plump, brightly colored seeds as seeds.
② Seed treatment: Soak the seeds in warm water at 50-60°C for 10 minutes, mix with fine sand and rub to remove the waxy coating, then sieve out the seeds. Stratify and store them with 3 times their volume of moist sand in a wind-sheltered, sunny pit, covering with grass to keep warm and moist. When about 50% of the seeds crack open and show white in the following spring, take them out for sowing. For autumn sowing, sow immediately after harvest. At this time, the fresh seeds should be soaked in warm water with wood ash added for 3-5 days, rubbed to remove the waxy coating, watered frequently, and sown after the seeds crack.
③ Seed sowing: The seedbed should be made into raised beds 1.2 m wide and 30 cm high, with paths 30 cm wide. On the bed, open furrows transversely at a row spacing of 20 cm for drilling, with a sowing width of 5 cm and a furrow depth of 6 cm. After sowing, cover with 3 cm of soil and then with rice straw. Sow in early March, and full emergence can be achieved in mid-to-late May. Autumn-sown seeds can emerge in about a month. After emergence, promptly remove the covering, insert branches for shade, and water frequently to maintain a moist environment. Strengthen management, remove weeds and apply topdressing. After two years of cultivation, they can be planted out.
2. Division propagation: In late winter and early spring, dig up old plants with tillers, keeping the roots, and plant them immediately as they are dug.
3. Layering: In early spring, gently press small branches of the parent tree near the ground into the soil without breaking them, cover firmly with soil and secure with crossed stakes, so that the branches grow tender roots and new shoots at the ground level. After one year, they can be planted out.
4. Air layering: In late June, select young tender branches on the parent plant. At a branching point, use a knife to cut away the bark of the branch, cutting it into a semicircular shape. Wrap with plastic film or a bamboo tube, fill with moist fertile soil, and tie tightly with rope on the outside to prevent movement and keep moist. In late April of the following year, check that new roots have formed, then remove and plant out.
5. Cutting propagation: In summer and autumn, select 1-2 year old tender branches and cut them into 15-20 cm long cuttings, with the upper end cut flat and the lower end cut into a horseshoe shape. After moistening, dip in a powder composed of 500 ppm indolebutyric acid and talcum powder, then insert obliquely into the seedbed, leaving 2 nodes at the lower end and exposing one node above the ground. Build a shade frame and keep the soil moist. Roots can develop in about 1 month.
6. Grafting propagation: Seedling plants from seed propagation need 7-8 years of cultivation to bloom. Using grafted seedlings for planting, they can bloom in only 2-3 years. Commonly used grafting methods include "bud grafting" and "cut grafting". Both cut grafting and bud grafting are the same as for general flowering shrubs.
Planting methods of Magnolia denudata
1. Transplant preparation: Carry out deep plowing and land preparation in autumn and winter. In the following spring, make beds 1-1.5 m wide. During land preparation, fertilize and weed to ensure vigorous growth of seedlings after transplanting.
2. Transplanting time: The suitable time for transplanting is when the seedlings have grown 2-3 true leaves after emergence. One to two days before lifting seedlings, if the weather is dry and the soil is compacted, water the transplant seedlings thoroughly once a day. When lifting seedlings, in order not to damage the root system, if the soil is relatively compacted, use a small shovel (2-3 cm wide) inserted into the soil at a 45° angle to help loosen the soil. Then lift the seedlings upward until the root system is completely lifted out of the soil surface.
3. Timely planting: The planting hole can be dug temporarily with a small shovel at the time of transplanting. Place the seedling upright, bury the root crown 1-2 cm into the soil, press the soil firmly with your hands, and then water.
4. Light and temperature: It is suitable for growing in an environment with sufficient sunlight. Sufficient light can make the plant lush with branches and leaves, with more flowers and more fragrance. It can endure short-term low temperatures of -20°C. In the Zhengzhou area, it can overwinter in the open field. In the Beijing area, it can generally also overwinter in the open field, but when the temperature is below -20°C, cold protection measures are needed. It is relatively sensitive to temperature; high temperatures can make the flowering time earlier.
5. Watering and fertilizing: Fertilize twice a year, one is the wintering fertilizer, and the other is the post-flowering fertilizer. Dilute decomposed human manure and urine are preferred. Avoid concentrated fertilizer. Watering can be done as appropriate: less on cloudy days, more in dry periods. In spring, growth is vigorous and water demand is somewhat greater, so water thoroughly twice a month. In summer, it can be slightly more. In autumn, reduce the amount of water. In winter, generally water little, but if the soil is too dry, water once.
6. Shaping and pruning: Carry out after flowers fade and before leaf buds sprout. Generally, do not prune, because magnolia branches have poor callus-forming ability. Do not carry out major shaping and pruning. Only cut out overly dense branches, water sprouts, crossing branches, dead branches, and diseased and pest-infested branches to cultivate a reasonable tree shape and make the posture graceful. Directly apply callus and antiseptic film to cut and saw wounds to quickly form a tough soft film closely adhering to the wood, protect the growth of wound healing tissue, prevent infection by decay pathogens, prevent soil and rainwater contamination, prevent freezing, and prevent wound cracking.
7. Flowering period control: If you want potted magnolia to bloom at New Year's Day or the Spring Festival, move the potted magnolia into a low-temperature greenhouse 40-50 days in advance to gradually break dormancy. After 25-30 days, move it to a high-temperature greenhouse, maintain air humidity above 60%, and spray flower stalk strengthening agent. It will then bloom at the desired time, which can promote strong flower buds, plump petals, bright flower color, rich fragrance, and extended flowering period. How to make potted Magnolia denudata flowers large, numerous, fragrant, brightly colored, and long-lasting? The key is to strengthen the flowering period management of potted Magnolia denudata.
8. Pest and disease control: The main insect pests of Magnolia denudata flowers are aphids and scale insects. In the management process, in addition to preventing and controlling yellowing disease and root rot, anthracnose should also be controlled. For scale insect damage, spray with 0.3% to 0.4% acid vinegar solution, or remove them by hand. Aphids damage tender buds and flower buds. They can be killed with sumethion, or sprayed with a 500-fold solution of washing powder, or removed by dipping a cotton swab in washing powder solution to stick off the pests, then spraying and washing the branches and leaves with clean water. If disease is found, promptly remove diseased plants and diseased leaves, and at the same time spray the leaves with a 500-fold to 800-fold aqueous solution of 50% carbendazim, or use a 800-fold to 1000-fold solution of 70% thiophanate for control.
Cultivation management of Magnolia denudata
Cultivation management of Magnolia denudata
(1) Overview
Magnolia denudata, also known as magnolia, yulan flower, and Yutangchun, belongs to the genus Magnolia in the family Magnoliaceae. It is produced in Anhui, Zhejiang, Hubei, Hunan, Guangdong and other provinces of China, and grows wild in mountainous areas at altitudes of 500-10000 m, often mixed with evergreen broad-leaved forests. Magnolia denudata is a unique famous flower of China. Its flowers are large and white, and the fragrance resembles that of orchids, hence the name. In early spring, the tree is full of flowers, and after flowering, the branches and leaves are luxuriant and the tree posture is magnificent. In autumn, green leaves and red fruits present a distinctive charm. In ancient and modern gardens, it is often planted together with pavilions, terraces, towers, and chambers. If planted with pine trees and landscape rocks, it feels even more naturally antique. If planted in clumps or patches, during full bloom it is like snow waves and clouds, with a magnificent atmosphere. Magnolia denudata has relatively strong resistance to harmful gases such as sulfur dioxide and chlorine, and can be planted in green areas of industrial and mining districts. The bark and petals can be used as medicine.
(2) Cultivation methods
Magnolia denudata likes warm and humid environments. When planting Magnolia denudata in North China, choose a site that is sheltered from wind, sunny, does not accumulate water, and has side shade. Neutral sandy loam with good drainage is suitable.
(3) Management key points
During the growing season, keep the soil moist and water thoroughly once a month. Soil drought can cause flower buds to drop and affect flowering the following year. Stop watering during the rainy season and pay attention to drainage and waterlogging prevention. In mid-to-late November, water sufficiently for freeze protection, and immediately bury soil for cold protection after the water infiltrates, so as to facilitate safe overwintering. After leaf fall in autumn, prune moderately. In addition to cutting off dead branches, long branches should also be cut to 12-15 cm, while medium and short branches are generally not pruned. The cut should be no less than 1 cm from the bud. Old branches should be sawed off in time to facilitate renewal.
(4) Transplanting and planting
When using seed propagation, place the fruits in cold water, rub and wash away the red aril, take out the seeds and air-dry them slightly indoors, then store them in moist sand at 0-10°C. In early March of the following year, sow in pots or wooden boxes indoors by dibbling. After sowing, they can germinate and emerge in 20 days. In late April, they can be transplanted into flower pots or open-field seedbeds. Four-year-old seedlings can be planted out. Magnolia denudata is not suitable for bare-root transplanting.
Key management points for cultivating magnolia in cold regions
Magnolia flowers are as white as jade and as fragrant as orchids. They are a famous early spring flower in China and an excellent tree species for landscaping. However, planting in green areas in cold regions requires corresponding technical measures to maintain long-term survival. In the spring of 1997, 100 magnolias were planted in Huaxia Community, Benxi City, Liaoning Province. So far, the survival rate has reached over 95%, and all are growing well with luxuriant branches and leaves. After more than 10 years of cultivation and maintenance, Benxi magnolias have become a successful magnolia scenic belt planted in landscaping green areas in cold regions.
Before planting magnolia, prepare the culture soil in advance. Method for preparing culture soil: take 5 parts humus soil, 5 parts garden soil, and 2 parts sand, and mix thoroughly and evenly to ensure a good growing medium for magnolia.
Lifting seedlings with soil balls is one of the key technical measures for the survival of magnolia cultivation. The diameter of the soil ball is about 8 to 10 times the diameter at breast height of the magnolia. Pack it with straw rope or straw bands to ensure that the soil ball does not scatter or crack during transportation.
When digging the planting hole for magnolia, the hole diameter should be 40 cm to 60 cm larger than the diameter of the soil ball, and the hole depth should be suitably 10 cm to 20 cm higher than the height of the soil ball. The hole should be standard, avoiding a pot-bottom-shaped hole. Place the magnolia soil ball into the hole, remove the straw bands or straw rope as much as possible, and while filling with soil, use the back of a shovel or a wooden stick to tamp the soil firmly. Be careful not to damage the soil ball. Fill the soil to the root collar of the seedling.
After the magnolia is planted, build a berm around the outer edge of the hole, with a height of 15 cm to 20 cm and a bottom width of 20 cm to 30 cm. Tamp the two sides and the top firmly with a shovel. After the soil berm is built, water into the soil berm within 24 hours, with the amount of water sufficient to soak through. Thereafter, water according to weather conditions. If the weather is relatively dry, water thoroughly a second time after 3 to 4 days, and a third time after 7 to 10 days. After the third watering is finished, wait for the water to seep down and then seal the hole. If there is a long drought later, water appropriately.
Pruning should be done before or after planting, combined with beautifying the tree shape, mainly cutting off water sprouts, weak branches, overly dense branches, drooping branches, injured and bark-damaged branches, diseased and pest-infested branches, and dead branches. Two methods, heading back and thinning, can be used for pruning, so as to achieve good ventilation and light penetration, beautiful shape, and favorable growth for magnolia.
After flowering, from May to June, apply topdressing once to facilitate flower bud formation. Decomposed liquid fertilizer or compound fertilizer can be used. In autumn, appropriately increase the application of phosphorus and potassium fertilizers to magnolia, such as monopotassium phosphate, potassium nitrate, plant ash, etc. Fertilization can be done by the ring method, so as to make the magnolia branches and trunks fully lignified and improve the disease resistance and cold resistance of magnolia. After the soil thaws, apply decomposed organic fertilizer to magnolia each year as base fertilizer. Depending on the situation, methods such as trench application, hole application, and ring application can be used.
For overwintering cold protection technology, the following methods can be selected according to the specific cultivation situation of magnolia:
At the end of October or in early November, use a whitewash made by thoroughly mixing 10 parts lime, 1 part lime sulfur mixture, and 50 parts water to paint and spray the trunk and tree body white. This can reduce the harm from sudden temperature differences and can also kill some overwintering pests and diseases. To improve adhesion, an appropriate amount of salt can also be added to the whitewash.
Before the land freezes, water thoroughly once with freeze water. In this way, after freezing in winter, a frozen layer will form around the tree roots, maintaining a constant temperature for the tree roots and preventing them from being affected by sudden changes in external temperature. At the same time, soil moisture is increased, which can also prevent magnolia twig dieback. In cold regions, the time for watering freeze water should not be too early, otherwise it will affect cold resistance. Generally, water freeze water after frost and before Light Snow, depending on local conditions.
In mid-November, before the land freezes, after watering freeze water and in combination with sealing the berm, build a mound of soil at the root of the tree with a diameter of 80 cm to 100 cm and a height of 40 cm to 50 cm to prevent freezing injury to the tree roots and also reduce evaporation of soil moisture.
In winter, use straw rope to wrap the trunk tightly in layers or use rice straw to wrap the main trunk and part of the main branches for cold protection. Remove the wrapping after the late frost in spring.
To reduce damage to the trunk and branches caused by cold, dry strong winds, set up windbreaks on the windward side. Materials for building windbreaks can include sorghum stalks, vitex branches, reeds, etc. The height of the windbreak should exceed the tree height. Support it firmly with wooden sticks, bamboo poles, etc. to prevent it from being blown down by strong winds. Fill gaps where wind leaks with rice straw. Sometimes mud can also be applied to fill them. Snow accumulated under the magnolia tree can maintain a certain low temperature, avoid invasion by excessively cold strong winds, increase humidity and preserve soil moisture in early spring, lower soil temperature, and prevent buds from sprouting too early and being harmed by late frost.
Spring irrigation: Water promptly in early spring when the land thaws, and often keep the soil mound moist. This has a great effect on preventing drought and twig dieback in magnolia caused by spring winds.
Pest and disease control: The common disease of magnolia is anthracnose, which can be controlled by strengthening maintenance management or by using chemicals. Promptly remove diseased leaves and cut off diseased shoots. Promptly burn diseased leaves, fallen leaves, and residual branches. Avoid excessive moisture, pay attention to drainage, and maintain good ventilation and light penetration. In the early stage of disease onset, spray 500-fold solution of 50% carbendazim wettable powder, 500-fold solution of 50% thiram wettable powder, or 1000-fold solution of 70% thiophanate-methyl wettable powder for control.
Common insect pests of magnolia include red wax scale, white grubs, cutworms, wireworms, jewel beetles, and longhorn beetles. Physical and chemical control methods can be adopted as appropriate to remove and control them.