Cultivation and Management Key Points of Dianthus Chinensis and Analysis of Its Extension Value

Dianthus chinensis is a perennial herbaceous plant of the genus Dianthus in the family Caryophyllaceae. It originated in Austria and Siberia, and was introduced from Siberia in 1989 by the Changyi City Nursery in Shandong Province. Later, with the help of Shandong Agricultural University and other research institutes, related cultivars were also introduced from Canada, Japan, the United States and other places. After 7 years of crossbreeding, domestication and improvement, 3 series and 36 cultivars were successively bred: "Changhua" (1995), "Huadu" (1997) and "Xueyuan" (2000) (with strong resistance, large flowers and more beautiful flower colors). At present, trial planting has succeeded in the northwest, northeast and the Beijing, Tianjin, Hebei and Shandong regions, and two major Dianthus chinensis production bases have been established in Changyi City, Shandong Province and Beijing.

1 Extension value

Dianthus chinensis grows in clumps, 8-10 cm tall, dark green, smooth and covered with a white powder. Its umbel-like inflorescences include deep pink, light pink, white and bicolor, with a flowering period from May to November. It has extremely strong drought and cold resistance and can overwinter at -35°C. After planting and establishment, it can rely on natural rainfall alone, saving about 70% water compared with ordinary lawns. It has many, fragrant and dense flowers, and in full bloom it covers the ground. Its growth is low, so it needs few trimmings. Its perennial root system is extremely strong (with a lifespan of more than 8 years). Therefore, it has great ornamental value and is an excellent new type of low-maintenance lawn plant.

2 Cutting propagation

Dianthus chinensis is a hybrid cultivar. Apart from using F1 generation seed, it cannot be propagated by seed, otherwise degeneration and variation will be severe. Cutting propagation, however, is simple, has a high survival rate, is fast and keeps the genes stable, making it suitable for factory production.

2.1 Seedbed preparation

Because Dianthus chinensis dislikes waterlogging, it is best to choose well-drained sandy soil with a certain slope. Then deep plow, apply fertilizer, prepare the land and make beds. Apply 2000 kg of organic fertilizer per mu, make raised beds 1 m wide, and leave a 30 cm wide water channel between two beds for drainage. Irrigate in the dry season to keep soil moisture at about 70%.

2.2 Selection and treatment of cuttings

Select strong branches free of pests and diseases, cut them to about 5 cm, and remove 2/3 of the leaves on the branches to reduce water evaporation. After cutting, disinfect by soaking in a 1000-fold carbendazim solution for 10 minutes, and use NAA as a rooting agent. Then remove them, drain off the liquid medicine, and place them in a cool place for later use.

2.3 Cutting technique

2.3.1 Cutting method A ground temperature of 5-25°C is suitable for rooting and favorable for cutting. First use a thin wooden stick to make small holes 2 cm deep in the bed, insert the cuttings into the holes, and firm the soil around them. Use a plant spacing and row spacing of 3-5 cm, and be careful to spray water to maintain moisture.

2.3.2 Post-cutting management After cutting, the temperature should not exceed 30°C, and the relative air humidity should be controlled at about 80%. In summer and autumn, use a shade net to provide 60% shading, and combine this with artificial misting to lower the temperature (misting once every 2 hours). Roots form in 15 days. After that, during the 2-4 leaf stage of about 1 month, spray a 500-fold monopotassium phosphate solution to promote tillering.

3 Cultivation management

3.1 Site selection and land preparation

Dianthus chinensis has no strict soil requirements. Because it dislikes waterlogging, choose neutral plots with good drainage and a low groundwater table, preferably sandy loam or sloped land. For vacant land after construction projects are completed, deep plow more than 40 cm, pick out debris such as crushed stone, brick and cement, and then mix in 50% high-quality loam. At the same time, apply a slow-release compound fertilizer mixed with decomposed farmyard manure as base fertilizer, at 1000 kg per mu. Then properly disinfect the soil (note that disinfection and fertilization should not be done at the same time). After leveling the soil, roll it once and irrigate thoroughly, allow the land to settle naturally for 2-3 days, then level it again before planting. To prevent weeds from growing, spray a chemical herbicide 20 days before planting.

3.2 Transplanting

Except for the winter freezing period and the summer high-temperature and high-humidity season, planting can be done at other times. The best times are after the Beginning of Autumn (mid-September to early November) and in spring (early March to mid-May). For spring transplanting, it is best to use small seedlings; in autumn, division propagation can be used. Specific method: transplant at the 4-6 leaf stage. Water the seedbed 2 days before lifting the seedlings, keep protective soil around the roots, and open holes in the pre-prepared plot at a plant spacing and row spacing of 20 x 30 cm. Generally, small clumps (below 6 cm) do not need to be split, while large seedlings (above 10 cm) can each be split into 4-6 small clumps, and the split small clumps must have fine roots, otherwise they are not easy to survive. Plant at a depth about 1-2 cm deeper than the original seedling, firm the soil after planting, and irrigate thoroughly once with water to settle the roots.

3.3 Fertilizer and water management

Dianthus chinensis is drought-resistant but not waterlogging-tolerant. In water management, follow the principle of preferring dryness to wetness, and water flexibly according to drought conditions. At the same time, to make it grow rapidly and vigorously with large and brightly colored flowers, water and topdress in stages. Generally, water 3 times per year: the 1st is green-up water (early spring); the 2nd is flowering water (full bloom in mid-May); the 3rd is freezing water (late November to early December), which helps it overwinter safely. For newly planted seedlings, pay special attention that the 1st watering is sufficient and thorough, then after 3-5 days, water 1-2 more times depending on the weather and soil drought conditions. In summer, pay attention to drainage, otherwise waterlogging for more than 2 days can kill more than 90% of the seedlings. Generally, topdressing should be combined with watering, and a multi-element compound fertilizer should be broadcast once before watering.

3.4 Disease control

3.4.1 Physiological diseases are usually caused by imbalances in nutrition, water and temperature or by infection with harmful substances. If not controlled in time, diseased seedlings will be repeatedly infected, causing the disease to become epidemic and the plants to die. Therefore, when planting, the base fertilizer should mainly be soil and miscellaneous manure, and topdressing should mainly be phosphorus and potassium fertilizers. Keeping the ground appropriately dry in the high-temperature season is an important measure to prevent physiological diseases. In addition, the lawn surface should often be kept clean and sanitary, especially after pruning, when the pruned material must be removed cleanly. This not only ensures the air permeability of Dianthus chinensis but also reduces latent pathogens.

3.4.2 Pathological diseases are mainly leaf spot and damping-off caused by fungi, and mostly occur in the high-temperature and high-humidity season from July to September. Therefore, chemical control should be strengthened during this period, and mancozeb, chlorothalonil, thiophanate-methyl, carbendazim and others can be used. For example, in the rainy and high-humidity season or after pruning, be sure to spray a 500-1000-fold 50% carbendazim wettable powder solution, which gives a good effect.

3.5 Pruning

The leaf growth cycle of Dianthus chinensis is 100-120 days. If pruned too early, the new leaves age too early and the green period in winter is short; if pruned too late, the new leaves are too tender, affecting the ornamental effect. Therefore, timely pruning is the key to managing Dianthus chinensis. Usually prune 3 times per year: the 1st in late May to early June, starting when 70% of the spent flowers appear in full bloom; the 2nd in late June to early July, a heavy pruning (adjust the lawn mower blade to the lowest position) to give Dianthus chinensis good ventilation and help it pass the summer safely; the 3rd in early to mid-September, and this pruning is an important means of achieving evergreen winter color. If growth is too vigorous, the number of prunings can be appropriately increased to ensure ventilation, but the pruning height should generally be 1/4 of the plant height.