How to propagate dawn redwood? A detailed guide to planting and cultivation techniques
Dawn redwood propagation, planting and cultivation techniques.
Dawn redwood
1 Propagation and seedling raising
1.1 Cuttage propagation. The rooting ability of dawn redwood cuttings decreases with increasing tree age, so cuttings are generally taken from 1- to 3-year-old seedlings.
1.1.1 Spring cuttage. Generally, cuttings are 10-15 cm long, cut flat at the upper end 1 cm from the bud, and cut obliquely at the lower end. As for the part of the branch from which cuttings are cut, the tip section and middle section of young trees are better, and they should be inserted as soon as they are collected. To improve the survival rate of dawn redwood cuttings, in addition to treatment with growth hormones, the "winter storage" method for cuttings is generally used. In winter, cut vigorous branches from mother trees into cuttings, tie them into bundles of 60-100 according to thickness, choose a sheltered, sunny place with good drainage, dip the bases of the bundled cuttings in slurry, and bury them upright in wet sand, covering them with matting to prevent the soil from freezing and rain and snow from entering and rotting the cuttings. Practice has proved that after winter storage, the basal tissue of dawn redwood cuttings softens, rooting after insertion is easier, and this helps increase the survival rate and the rate of seedling formation. After dawn redwood cuttings are inserted, the temperature rise is not great; as long as they are watered appropriately to keep the seedbed moist, there is no need to shade them immediately. This can raise soil temperature and benefit rooting of the cuttings. After late April, begin shading; on sunny days cover early and uncover late, and do not cover on cloudy and rainy days. After the dog days, gradually shorten the shading time, and after early September, shading may be stopped. Loosen the soil and weed frequently. After the cuttings root, apply topdressing 2-3 times to promote seedling growth.
1.1.2 Summer cuttage. Late May to early June is suitable, when the maximum temperature reaches 27 degC-28 degC. Collect cuttings on clear mornings before the dew has dried, selecting semi-lignified young shoots 14-18 cm long, retaining the top shoot and the upper 4-5 pinnate leaves, and insert them 4-6 cm into the soil, at 70,000-80,000 cuttings per mu. Young shoots have vigorous physiological activity and strong regenerative ability, and generally root 20-25 d after insertion. Shade after insertion and spray 3-5 times daily to keep the seedbed moist. From late August, gradually shorten the shading time, and after late September the shade frame may be removed to promote lignification of the seedlings and help them overwinter.
1.1.3 Autumn cuttage. This can be done from the end of August to early and mid-October, before leaf fall begins. Cuttings should be selected from branches with short internodes and vigorous growth; avoid using long-internode water sprouts for cuttings. Cuttings are 12-20 cm long and preferably carry the top shoot or terminal bud. When collecting shoots and cutting cuttings, promptly place the shoots and cuttings in a bucket or basin of water to keep the cuttings moist. On the prepared bed surface, cuttings may be inserted in water, or a thin stick may be used to make holes for dry insertion, with a plant-row spacing of 3 cm x 10 cm. If not moved to another bed, the plant-row spacing may be 5 cm x 15-20 cm. After insertion, water thoroughly the first time. For early autumn cuttage, the temperature is still high, so shade appropriately and water frequently to keep the seedbed soil moist. For later cuttage, water appropriately and no shading is needed. In about 1 month the cuttings heal and root. After the first frost arrives, cover with plastic film to keep warm and let light through, which benefits root development of the cuttings; in March of the following year, move them to the bed at a certain plant-row spacing for planting to cultivate large seedlings. Dawn redwood autumn cuttage has a long period, a wide source of shoots, and good results.
1.2 Seed propagation. Dawn redwood seeds are scarce, and for a small amount of seed it is best to use nutrition-cup seedlings. For seed propagation, choose a plot with sufficient water, good drainage, few pests and diseases, and fertile, loose soil. Prepare the land and make beds carefully, and apply sufficient base fertilizer. The sowing time is generally March-April, suitable when the ground temperature reaches 12 degC. Drill sowing (row spacing 20-25 cm) or broadcast sowing, with a sowing rate of 1-1.5 kg per mu. Before sowing, irrigate enough bottom water, mix the seeds with fine sand for sowing, and cover with soil to a thickness that just hides the seeds. After sowing, cover with grass and sprinkle water appropriately; germination begins in about 10 d, and after the seedlings have basically emerged, promptly remove the covering grass and provide shade. During seedling growth, promptly pull weeds, loosen the soil, water, and apply topdressing several times. After September, gradually remove the shade frame. One-year-old seedlings can reach more than 40 cm in height. The following spring they can be lifted for planting or moved to beds to cultivate large seedlings.
2 Afforestation
Dawn redwood is used for seedling planting afforestation. For "four-side" greening, 4- to 5-year-old large seedlings should be planted, with a plant-row spacing of 3 m x 4 m or 4 m x 6 m. For mountain afforestation, choose gentle slopes at the foot of mountains with deep, fertile, moist soil, and gullies, stream sides and mountain hollows with good drainage. Generally, 2- to 3-year-old seedlings are better. For block planting, the plant-row spacing at initial planting density may be 2 m x 3 m. When planting large dawn redwood seedlings, be sure to carry plenty of native soil, retain lateral roots as much as possible, and plant as soon as they are lifted to avoid wind and sun affecting survival. Planting in late winter is better, as it facilitates rapid recovery of roots damaged during lifting and gives a higher survival rate.
3 Pest and disease control
To control dawn redwood red blight, during the disease period spray 1:200 Bordeaux mixture, or 50% thiophanate wettable powder; immediately after the plum rain season ends, spray the tree crown with 1% Bordeaux mixture 4-5 times, once every 10-15 d, which can control the occurrence of the disease. To control the bagworm, use trichlorfon 800-1,000 times solution or fenitrothion 1,000 times solution to spray and kill the larvae.
Dawn redwood cultivation and management techniques
Dawn redwood is a deciduous tree of the genus Metasequoia in the family Taxodiaceae, native to Sichuan, and is now widely cultivated in Beijing and areas to the south. The dawn redwood has a tall, upright posture and elegant leaves, is suitable for specimen planting or row planting, and is a good material for landscaping. Its main cultivation techniques are introduced below for reference only.
Morphological characteristics and ecological habits
The dawn redwood can reach 30 m in height. Young trees have a pointed tower-shaped crown, while old trees have a broad rounded crown. The bark is grayish brown, roughly nearly whorled, and the branchlets are opposite. The leaves are decussate-opposite, twisted at the base and arranged in 2 rows, pinnate, linear, flat, 1 cm to 4 cm long. It is monoecious with unisexual flowers. The cone is nearly spherical, 2 cm to 3 cm long, dark brown when mature, drooping; the seeds are flat, obovate, with narrow wings.
Dawn redwood is a sun-loving tree, and grows poorly when planted in the shade behind buildings. It is cold-resistant and can overwinter safely in Beijing and areas to the south. It likes deep, fertile sandy loam, can also grow normally in plain sandy soil, and does not like clayey soil. It has a certain salt-alkali tolerance and can grow normally in mildly saline-alkali soil with pH 8.7 and a salt content of 0.2%. It likes moisture but is not waterlogging-tolerant, nor drought-tolerant. It has strong resistance to many toxic and harmful gases such as sulfur dioxide and chlorine.
Water and fertilizer management Dawn redwood likes a moist environment but is not tolerant of standing water, so water management is especially important.
For newly transplanted dawn redwood, the soil should be kept at about half moisture, neither too dry nor too wet. In the early stage after transplanting, water the first three times well; after that, water thoroughly once a month; in the rainy season, water less or not at all; and at the end of autumn, water well for freezing protection.
In early spring of the following year, water promptly for thawing; after that, still water thoroughly once a month, and after heavy rain promptly drain the accumulated water in the tree pit to prevent root rot from excessive water. In the third year, water as in the second year. From the fourth year on, only thawing water and freezing water are needed each year; in other seasons, if it is not too dry, it can rely on natural precipitation for growth. For newly transplanted small seedlings, in addition to normal watering, if conditions permit, leaf spraying can be carried out to help the plants recover.
Dawn redwood likes fertilizer. When transplanting, apply sufficient base fertilizer; dried chicken manure or cow and horse manure may be used, and sheep manure may also be used, but all should be thoroughly composted and fermented. The base fertilizer should be mixed evenly with the cultivation soil. In late autumn of the planting year, a little leaf mold fertilizer or cow and horse manure may be applied lightly. In early spring of the following year, apply urea once together with thawing water; in mid-to-late June, apply a three-element compound fertilizer once; do not fertilize in autumn. In early winter, fertilizer may also be applied as in the first year. From the third year on, apply urea once each early spring.
Pest and disease control - diseases The common disease of dawn redwood is damping-off, which mainly occurs at the seedling stage. On affected seedlings, reddish-brown irregular or elliptical lesions appear on the main root and the stem base at ground level. In the early stage of the disease, the stems and leaves of diseased seedlings wilt during the day and recover at night and early morning. The lesions continue to expand outward and gradually become sunken, finally encircling the stem once, and the stem base turns brown and rots. In some cases the xylem is exposed, and the cortex cracks in an ulcer-like manner; finally the diseased plant shrinks and dries up and the plant dies, but it generally still stands without falling, hence the name damping-off.
Under moist conditions, light brown spiderweb-like mycelium can be seen on the diseased parts and nearby surface soil; it is not prominent, and later granular sclerotia form. There is no obvious white cottony mold on the diseased parts, which distinguishes it from damping-off of seedlings.
Control of damping-off should begin at the propagation stage. First, choose a place for seedling raising with high terrain, good drainage, convenient water sources, and shelter from wind and facing the sun. Second, strengthen seedbed management, and select fertile, loose, disease-free new bed soil; if old bed soil is used, it must be disinfected. Fertilizer must be fully composted and applied evenly. When watering according to soil moisture and weather conditions, each watering should not be too much, and it should be done in the morning. When the bed soil is too moist, scatter dry fine soil to reduce moisture. While doing a good job of keeping the seedbed warm, provide more light and moderate ventilation.
If damping-off occurs, spray 65% chlorothalonil wettable powder 600 times dilution, 60% mancozeb wettable powder 500 times dilution, or 62.2% propamocarb aqueous solution 600 times dilution. Spray once a week, and two or three consecutive sprays can effectively control the disease.
Insect pests Common pests of dawn redwood include white grubs, bagworms and pine-oak caterpillars. If white grubs occur, use 3% isofenphos-methyl granules, 3% carbofuran granules, or 5% phoxim granules, applying 2.5 kg to 3 kg per mu to treat the soil. If bagworms occur, use light traps to kill male adults, and during the larval stage spray 1.8% abamectin 3,000 times solution to kill them. If pine-oak caterpillars occur, use light traps to kill adults, and during the young larval stage spray 3% high-permeability fenoxycarb emulsifiable concentrate 3,000 times solution to kill them.
Pruning and shaping The crown of dawn redwood can naturally grow into a conical shape, so in cultivation try to maintain the natural tree shape. At the seedling stage, pay attention to protecting the branches at the base of the trunk, and do not let it form a bare-legged trunk. At the sapling stage, according to the tree shape, thin out overly dense branches, and some water sprout branches may be shortened to prevent them from disrupting the tree shape. In addition, promptly prune out diseased and pest-infested branches.
Propagation methods Dawn redwood has two propagation methods: sowing and cuttage. Because cuttage is simple and easy and can produce a large number of seedlings at one time, cuttage is often used for propagation.
Cuttage is mainly spring cuttage. The mother plant for collecting cuttings is best a seedling from seed, preferably 3 to 5 years old, and one-year-old branches may be selected as cuttings. The cuttings are 10 cm to 12 cm long, with the lower cut in a horseshoe shape, in bundles of 10; before insertion they may be quickly dipped in ABT rooting agent, which can effectively promote rooting of the cuttings. The plant-row spacing for cuttage is 50 cm x 50 cm. After insertion, spray water promptly, then cover with a frame. After early May, set up a shade net so they do not receive strong midday sunlight. In late May, the plastic frame may be removed, and spraying is done three times daily in the morning, noon and evening. In mid-July, apply a three-element compound fertilizer once as topdressing. In late autumn, scatter cow and horse manure at a thickness of 10 cm, then spray once with 75% chlorothalonil wettable granules 1,000 times solution, and then cover with a frame for cold protection.
In early April of the following year, after budding, transplant at a plant-row spacing of 80 cm x 80 cm. During management, pay attention to pulling weeds, and after irrigation loosen the soil to preserve moisture. In the third year, transplant at a plant-row spacing of 150 cm x 150 cm. In the fourth year they can be lifted for outplanting.
Dawn redwood cultivation techniques
Dawn redwood is a specialty of our country. It likes light and moisture, grows fast, and can be propagated by both sowing and cuttings. It is an ideal tree species for landscaping.
1. Ecological habits: Dawn redwood is a large deciduous tree of the genus Metasequoia in the family Taxodiaceae. Dawn redwood likes sunlight, is relatively cold-resistant, and is not shade-tolerant; it has strong adaptability and grows best in deep, fertile, moist acidic soil;
2. Cultivation: When planting, plant as soon as the seedlings are lifted. If long-distance transport is needed, before planting soak the seedling roots in water so they absorb enough water and survival is promoted. Before planting, dig large holes, apply base fertilizer, and do not injure the roots. After planting, irrigate fully, thoroughly and completely, and spray the seedlings with New High Lipid Film to shorten the recovery period.
3. Management: During the growing period, topdressing may be applied. At the seedling stage, appropriate pruning may be done (the pruning cuts need to be coated with wound-healing and antiseptic film). After 4-5 years, do not prune, so as not to damage the tree shape. Small seedlings are planted with mud slurry, and large seedlings must be planted with a soil ball. Planting in spring gives a high survival rate. It is tolerant of pruning and can be cut into a spherical shape and used as a hedge. Euonymus japonicus is evergreen all year round, tolerant of pruning and wiring, grows rapidly, and is easy to survive; it is a good material for pruning, shaping and hedges, and can also be used for ornament.
4. Landscape uses: The trunk of dawn redwood is straight and upright, tall and elegant, with emerald green leaves that turn golden yellow after autumn. It is a famous ornamental tree for courtyards. Dawn redwood can be planted as a specimen, in rows, or in groups in parks, courtyards, lawns and green spaces. It can also be planted in blocks to create scenic forests, and matched with evergreen groundcover plants; dawn redwood can also be planted in front of buildings or used as a street tree, with good effects in all cases.