Common family flower care and appreciation of dahlia
English name :
ahlia pinnata
, alias: dahlia, dahlia,
is a perennial herbaceous flower of the Asteraceae family and the genus Dahlia.
[Overview]
Dahlia, also known as dahlia, is a plant of the genus Dahlia of the Asteraceae family. Dahlia has many varieties, various flower shapes, rich colors, and a long flowering period. It is one of the world's famous flowers.
Since dahlia was transformed from wild to domestic by Mexicans in 1519, it has developed rapidly. In the early 19th century, Germany had cultivated more than 100 single-petal dahlia varieties, and then double-petal dahlia varieties were selected and bred in Germany. The cultivation of dahlias in the UK began in 1789. After the 1870s, double-petal varieties such as cactus-type, dwarf-type and peony-type were cultivated successively, providing conditions for potted dahlias. Since the 1930s, Japan, the United States, the United Kingdom and other countries have made remarkable achievements in the breeding of dahlias. Among them, the Pan American Seed Company in the United States and the Thompson Morgan Company in the United Kingdom are particularly outstanding in the breeding and production of dahlias. In recent years, the Dutch company Fides has taken the lead in the world in the breeding and production of potted dahlias.
The cultivation of dahlias began in the late 19th century, first in Shanghai, and later in Northeast China and North China. So far, the single-stem dahlias cultivated in Liaoning, Jilin, Hebei, Tianjin, Beijing, Shandong and Gansu are more gorgeous and noble, with a strong traditional color. At the same time, dwarf potted dahlias have entered large-scale production in big cities.
[Morphological characteristics and varieties]
Dahlias are perennial herbs. There are fleshy tubers underground, spindle-shaped, clustered. The stem is upright, smooth, branched, and hollow. The leaves are opposite, deeply pinnate, and the lobes are ovate. The head inflorescence is terminal, the ligulate flowers are varied and colorful, and the tubular flowers are often yellow. Common varieties include
the single-petal type Dandy, with a plant height of 60 cm, single petals, and a flower diameter of 9 cm. It is famous for its two-color varieties, among which the ligulate flowers are purple and the tubular flowers are white, which are more beautiful. Harlequin, plant height 31 cm, single flower, flower diameter 6 cm, among which the ligulate flowers are dark red, tubular flowers are white and the ligulate flowers are yellow, tubular flowers are white, which are particularly valuable. Mignon Silver, plant height 30-35 cm, single flower, wide petal, white, only 8 ligulate flowers. Piccolor series, plant height 20-25 cm, single flower, flower diameter 6-7 cm, flower colors include white, yellow, dark red, pink, orange-red and bicolor, etc. Semi-double and double types of Bambino, plant height 30-35 cm, flowers are sub-double, small, and belong to miniature. Figaro series, plant height 20 cm, semi-double and double flowers, flower diameter 6-8 cm, flower colors include yellow, orange, red, orange-red, dark red, purple, white, pink, etc. Rigoleto series, plant height 30 cm, double flowers, flower diameter 6-7 cm, flower colors include yellow, red, orange, pink, white, etc., belong to early flowering varieties. Sunny Hybrid Yellow, plant height 30-35 cm, flower semi-double, double, flower diameter 6-7 cm, flower yellow. The bronze leaf type includes the Diablo series, plant height 35-40 cm, double flowers, flower diameter 8 cm, flower colors include dark red, orange, pink, etc., leaves bronze, belong to early flowering varieties. Redskin, plant height 45 cm, double, semi-double flowers, flower diameter 7-8 cm, multi-color flowers, leaves bronze.
[Biological characteristics]
Dahlia is native to the Mexican plateau. It likes warm, humid and sunny environment.
The suitable temperature for the growth of dahlia is 10-25℃. In summer, it is more ideal for growth and flowering in cool areas with a temperature difference of more than 10℃ between day and night. If the temperature is higher than 30℃ in summer, the growth will be abnormal and the flowers will be few. If the temperature is lower than 0℃ in winter, frost damage will easily occur. The tuber storage temperature is preferably 3-5℃.
Dahlia is sensitive to water. It is not drought-tolerant and afraid of waterlogging. It is suitable for cultivation in areas with an annual rainfall of 500-800 mm. The middle and lower reaches of the Yangtze River often have heavy rainfall during the plum rain season, which is extremely unfavorable for the growth of outdoor potted dahlias, and they often wither and die due to waterlogging. Northwest and North China only need sufficient water, which is extremely beneficial to the growth and development of
potted dahlias. Potted dahlias like sufficient sunlight. The stems and leaves grow strong, and the flowers are many and colorful. But they are afraid of strong direct light for a long time, and they need proper shading to extend the flowering period.
The soil is preferably a mixture of leaf humus or peat soil and culture soil with good drainage and strong water retention. Potting soil should not be used repeatedly, otherwise the tubers are prone to degeneration and infection of pests and diseases.
[Propagation method]
Division, cuttings and sowing are commonly used for propagation.
Division propagation: It is carried out in March and April. The storage tubers are divided before germination. Since the tubers of dahlia are formed by the hypertrophy of adventitious roots on the stem base nodes, attention should be paid to the budding points on the old stems with root necks when dividing. Tubers without budding points cannot form new plants. Each tuber needs to have 1 to 2 buds when dividing, and do not hurt the young buds during operation.
Cutting propagation: It can be carried out from early spring to summer and autumn, and the survival rate of cuttings in the greenhouse from March to April is the highest. Plant the tubers in leaf humus with the top buds exposed to the soil surface. The room temperature is 15 to 22℃. When the top buds grow to 8 to 9 cm, leave a pair of leaves at the base, cut the cuttings, and transfer them to the sand bed. It can take root in about 15 to 20 days, and potted after 30 days, and it can bloom in the same year. It is also possible to cut the stem nodes with axillary buds during the stem and leaf growth period and insert them into the sand bed. It will take root 15 to 25 days after insertion, and the survival rate is high.
Sowing propagation: Indoor pot sowing is often used, with about 100 seeds per gram, the suitable temperature for germination is 20-22℃, germination 10-14 days after sowing, and the germination rate is 80%-85%. If the daytime temperature is 27℃ and the nighttime temperature is 18℃, it can germinate 5-7 days after sowing. It takes about 80-100 days for potted dahlias to bloom from sowing.
[Cultivation and management]
The sowing seedlings are transplanted 18 days after germination, and the temperature is controlled at about 16℃ in a 5-cm-diameter seedling tray. After 30-35 days, they are planted in 12-15 cm pots. Fertilize once every ten days during the growth period or use "Huiyou" 15-15-30 pot flower special fertilizer. Use 0.05%-0.1% dwarfing agent to spray the leaves 1-2 times 10 days after planting to control the plant height of dahlias. You can also pinch the top once when the seedlings are 15 cm tall to increase branches and make more flowers.
After the flowers wither, they need to be removed in time to reduce nutrient consumption and prevent the residual flowers from rotting and affecting the growth of stems and leaves. It can also promote the formation of new branches and extend the viewing time. During the growth process, watering should be strictly controlled to prevent the stems and leaves from growing too long, and to promote thick stems and large flowers. During the high temperature in summer, the leaves should be sprayed with more water, which is conducive to the growth of stems and leaves, but the potting soil should not be too wet. When the plant withers slightly before frost, cut off the stems and leaves, put them in a semi-shaded place, dig up the tubers after a few days, and store them in sand indoors.
[Disease and pest control]
Common powdery mildew and brown spot damage, in addition to paying attention to ventilation, can be sprayed with 50% thiophanate wettable powder 1000 times solution. Aphids and red spiders often occur in summer, and can be sprayed with 40% trichlorodicol emulsifiable concentrate 1000 times solution.
[Postpartum treatment] Dahlia has a wide range of applications, and dwarf and single-petal varieties are suitable for potted plants, flower beds and flower borders. Varieties with full flowers are suitable for cut flowers. Potted dahlias are packed for transportation or marketed when they are 30% to 40% in bloom in spring and 20% in bloom in summer. The tubers are stored in sawdust and the temperature is controlled at 4-7℃