Ornamental sunflower cultivation

Ornamental sunflower is an annual herb of the genus Asteraceae, native to North America. Because the disc inflorescence can be turned with the rotation of the sun, the name sunflower, also known as the sun, sunflower and sunflower. Ornamental sunflowers are full of plants and flowers. The flowers are large and colorful. They can be used as pot flowers, cut flowers, and garden flowers.

Botanical characteristics

Ornamental sunflowers vary greatly in plant height due to their different varieties, with short heights of only 20 to 30 cm and heights of up to 2 to 3 m. Some underground rhizomes are thick.

Ornamental sunflowers have bristles and hollow stalks. The shape of leaves is not much different from that of ordinary sunflowers. They are alternate, long-handled, with ovate leaves, green, pointed tips, and sometimes serrated leaves. Flower heads are planted on the top of the stem, commonly known as disk; cut flowers often have multiple branches, forming multiple disk. The disk shape has three types of raised, flat and concave. Disk diameter varies from 10cm to 20cm or more depending on the variety. Disk with ray flowers and tubular flowers, 1-3 tongue flowers, born at the edge of the flower disk, asexual flowers, with attracting insects to collect pollination honey. Tongue flowers are yellow, white, orange, reddish brown, purple black, etc. The petals have single and double petals. Tubular flowers are located on the inside of the ray flowers and are bisexual flowers.

The flowering period of ornamental sunflowers varies greatly depending on the sowing time and management measures. Conventional planting is generally open from June to September, and seeds mature in mid-September.

There are many kinds of ornamental sunflowers, such as potted plants, cut flowers, and flower beds, and they should be selected according to their needs. As the cut flower cultivation should choose cut flower varieties, the current common cultivars for hybrid F1 generation of non-pollen varieties, such as 'Golden 08', double flap 'golden auspicious' and 'Sanyang Kaitai' and so on. Dwarf sunflower's 'Laughter', 'Teddy Bear', 'Red Pura', 'Valentine' and other varieties, plant dwarf, generally 50 to 55 days after sowing can be flowering, suitable for potted plants and flower beds. Some cut flower varieties such as 'Sunshine', 'Jiuqiu', 'Italian White', 'Orange Yang' and 'Festival' can also be viewed as potted plants through the dwarf treatment of growth regulators.

Ornamental sunflowers are hi and warm, slightly tolerant to drought and require a sunny growing environment.

Introduced applications

The size of the ornamental sunflower is moderate, and it can be planted in front of a small courtyard window, wall, or fence, or it can be furnished with a balcony, a well-lit living room, a bedroom, etc. The potted plants are dotted with family gardens and windowsills, presenting a thriving atmosphere. It can be used to display public places and layouts in a variety of places to display a festive and warm scene.

Due to its golden color, long flowering period, longer vase insertion time, and straight stems, it symbolizes auspiciousness. It is used as a flower basket and bouquet flower arrangement, which is comparable to the variety of Xiaju. It is a new type of cut flowers worthy of promotion.

The cultivation history of ornamental sunflower is not long, but it has developed rapidly. Since the early 1980s, ornamental sunflowers have been used in Europe for only 100 years of cultivation history. The dwarf species, the heavy orange species, and the strong branching sunflower species were selected from single sunflowers, and the ornamental sunflowers entered the market of cut flowers and potted flowers. Then, European breeders set the direction of selection to dwarf, double and multicolor directions, making the ornamental sunflower a big step forward for potted plants. At present, ornamental sunflowers have been widely cultivated around the world.

The cultivation of ornamental sunflowers in China is not long. From the 1950s onwards, botanical gardens throughout the country were introduced from Europe, mainly as species specimens. Since the late 1980s, ornamental sunflowers have attracted people's attention and started to cultivate in small quantities. So far, new varieties have been continuously introduced and the scale of production has been expanding year by year. Ornamental sunflowers have been widely used in scenic spots and environmental arrangements, and have achieved good landscape effects.

At present, Henan, Guangdong, and other places have begun large-scale open-field sowing, Guangdong Panyu and Henan Zhengzhou and other places, have already had 1 million strains of "millions of sunflower garden."

Reproductive seedlings

It is mainly used for sowing and breeding. It can be sown all year round as required. Due to different uses, seedbed nursery, field direct seeding, seedling seedling cultivation and other methods are used. Usually used for sowing seedlings when making cut flowers.

Ornamental sunflower seeds vary greatly in their varieties, with 25 to 50 grains per gram for large seeds and 110 grains per gram for small seeds. Germination temperature is 21 °C ~ 25 °C. Commonly used sowing in open field, seeding plate with on-demand, 7-10 days after sowing germination, germination rate of 80% to 90%.

The specific sowing time is decided by the time of flowering, and can be sown all year round according to the application needs. Usually from January to April or September to October sowing, 60 to 70 days after sowing flowering; in May to August or November to December sowing, 70 to 80 days after sowing flowering. There is a difference in the time required between different breeds. If you plant from November to December, keep warm. Potted dwarf species generally take 50 to 60 days from sowing to flowering.

When seedlings are planted with plug trays, they should be sowed on deeper seedling trays. The matrix should be loose, the water holding capacity should be good, and the bacteria should be sterile. Generally, the mixture of peat, culture soil and sand is used as the seeding substrate. When sowing, the nutrient soil that has already been allocated is first loaded into the seedling tray, and the bottom water is allowed to be soaked until the water seeps. One seed was sown per hole, covered after sowing, and irrigated with water to keep the substrate moist. After sowing, cover 2 cm thick fine soil, compact the cover with a layer of plastic film, and put it in a dark place until it emerges. Germination temperature is 25°C and germination occurs from 3 days to 4 days. The kind of spacing is about 2cm, do not overtight, otherwise it is easy to "shell" emergence.

After emergence, attention should be paid to ventilation, cooling, humidity control, and gradually seeing light. The seedlings can be transplanted after being sown for 2 weeks to 5-6 cm. After emergence, seedlings should be divided in time and the seedlings should be transplanted into a 10cm10cm nutrient bowl for conservation. During this period, attention should be paid to the amount of water to avoid plant growth.

Daejeon direct sowing, dwarf cultivars sowing spacing 12cm12cm, large flower type, large plant type to increase the spacing of rows, 1 to 2 per hole. 10cm10cm spacing sowing in the soil with more residual fertilizer.

During the growing period, the substrate should not be too wet. At the same time, it is necessary to strengthen ventilation, enhance light and prevent the spread of fungal diseases. In the high temperature and rainy season, seedlings can be sprayed with 1000 times liquid of mancozeb and metalaxyl. After the cotyledon grows, spray with chlorothalonil or thiophanate-methyl 1000 times per week for 2 to 3 consecutive times to prevent the occurrence of damping-off.

Maintenance Management

The optimum soil temperature for transplanting seedlings is 15°C. In frost-free areas in winter, it is possible to grow in the fields, while in cold areas in winter, cultivation in greenhouses is required. If planting in high fertility fields, the planting density needs to be increased to limit plant growth and flowering. Sometimes the plant spacing is adjusted according to the soil's own fertility and the market's requirements for the thickness of the stem. When planting pelvic floor base fertilizer, dig the seedlings as much as possible with soil, less root damage, so that plants recover faster. Stop watering before planting, and pour the water immediately after planting, which will help promote new roots.

Soil management Sunflowers require less soil and can grow well in all types of soil. The most suitable sandy loam or loam with a pH of 5.8 to 6.5 is grown. Good soil permeability is essential for the growth of sunflowers. The soil is ploughed and loosened prior to sterilization and sowing to improve soil structure and drainage.

The plots of fields planted with ornamental sunflowers should be well-prepared in the autumn of last year, and the soil should be loose and fertile. Planting soil should be applied in appropriate amount to decomposed farmyard compost as a base fertilizer, applying 2,000 kg of organic fertilizer per acre, and adding some quick-acting fertilizers such as urea and diammonium, applying 10 kg per acre.

Potted ornamental sunflowers use a flower pot with a diameter of 10 to 15 cm depending on the size of the crown above the ground. Potted soil should be mixed with fertile garden soil, rotted leaf soil and coarse sand, and incorporate a small amount of decomposed livestock manure as base fertilizer.

Sunflower cut flowers are planted and the soil is used for continuous cropping. Open cultivation requires rotating land after planting 1-2 crops. Potted plants should do soil disinfection to prevent pests and diseases.

Water and fertilizer management Ornamental sunflowers have different moisture requirements at different growth stages. In open field cultivation, the root system is more developed, drought tolerance, spring watering is not much, and when the temperature rises in early summer and the amount of water evaporation is large, watering is needed. From sowing to budding, this period is relatively drought-resistant and requires little water. And proper drought is conducive to root growth and enhance drought resistance. The water should be properly controlled during budding period, but under conditions of strong sunlight and high temperature, due to tall plants, luxuriant leaves, and large water consumption, water should be promptly applied to prevent the wilting of leaves and affect the normal growth of plants, resulting in a decrease in the quality of cut flowers. . Flower budding is the peak period of water demand, this period of water shortage, a great impact on the amount of flower production, such as too much water to be added to the drought.

Potted ornamental sunflowers, large basins and small plants, should be watered in a timely manner during the growth period, otherwise the leaves will easily dehydrate and wither. However, it is not appropriate to water too much, and if the basin is too wet, the leaves will be yellow. Soil moisture is required for sowing and transplanting, after which the soil is required to be moderately moist. The seedling stage needs plenty of water and often keeps the soil moist. In early summer and when the temperature rises to 25°C to 28°C, the amount of evaporation is relatively large, and the amount of water should be increased.

The potted plants applied a thin liquid fertilizer or compound fertilizer every 7-10 days. The nitrogen fertilizer was the main seedling stage to promote the luxuriant foliage. After budding, more phosphorus and potassium fertilizers should be applied to provide sufficient nutrition to enable the buds to grow robustly. Help flowering. Can also be used fertilizer and water mixed drip irrigation system, according to the use of liquid fertilizer leaf color, to keep the bottom of the leaves can not be due to lack of fertilizer and yellow. It is also necessary to avoid fattening and controlling the use of liquid manure after emergence. When cutting flower pots, do not apply fertilizers to avoid excessive flower heads and thick stems, which is not conducive to bottle insertion.

If the soil is fertile, it can be planted without applying fertilizer. If the soil fertility is too poor, nitrogen fertilization is the main fertilization in the early stage, and phosphorus and potassium fertilizers will be added during the bud stage. The fertilization is applied once every 20 days during the growth period, but 2 to 3 thin phosphorus and potassium fertilizers should be applied before flowering.

Temperature light The adaptability of sunflower to temperature is strong and it is a warm and cold-tolerant plant. Sunflower seeds have strong low temperature resistance. When the local temperature is stable above 2°C, the seeds begin to germinate. When the temperature is 4°C～5°C, the seeds can germinate and take root. When the ground temperature reaches 8°C～10°C, they can meet the needs of seed germination and emergence. . The optimum temperature for sunflower development is 31°C to 37°C. The optimum daytime temperature for growth is 18°C ​​to 30°C, and the night temperature is 10°C to 18°C. During the entire growth process, the sunflower can grow normally as long as the temperature is not lower than 10°C. In the appropriate temperature range, the higher the temperature, the faster the development. If the temperature in early spring is low, the growth of plants is slow and directly affects the flowering time. However, when the temperature is higher than 30°C, the stems and leaves are long and the stems are slender, easily broken and the flowering period is shortened. Therefore, when cultivated in protected areas, ventilation should be carried out at a temperature above 25°C at noon, and thermal insulation should be performed at night temperatures below 13°C.

Ornamental sunflowers are hi-light flowers with strong phototaxis in their seedlings, leaves and disk. There is sufficient sunshine during the seedling period, and the seedlings are robust; the sunshine during the mid-batch period is sufficient, and the growth of stems and leaves and the differentiation of flower buds can be promoted. Ornamental sunflowers cultivated in open field have long illumination time and tend to bloom early; in winter, they are cultivated in the greenhouse, with short illumination time and delayed flowering.

If there is sufficient sunlight throughout the growth and development period, the stems and leaves will grow robustly, the flowers will be bright, and the ray flowers will be shiny; if the rain is continuous or grows in a semi-negative environment for a long time, the stems will not be upright, the leaves will be soft, sagging, yellow-green, and the flower disk is small. Not neat.

Plant management In order for the main shoots to develop robustly on the top buds, side shoots can be removed. For plants with slightly taller stalks, the props should be pulled to support the net during the windy season to prevent lodging of the plants. In the field cultivation, the bottom leaf should be vented in a timely manner to avoid the occurrence of diseases in the hot season.

Cut flower varieties should be removed from the top of the flower buds in order to facilitate the growth of lateral branches, so that the size of side branch flowers. After this treatment, 7 to 10 cut flowers per plant can be harvested. The length of the stem is 70 to 80 cm, and the height of the whole plant can reach 120 to 170 cm. Some species will grow buds at each festival and they must be removed in time to avoid dispersing nutrients and affecting the growth of buds.

If it is used for flowerbed viewing, it can be picked up once and branches can produce 4 to 5 flowers. Potted plants are better than single flowers. High culm cultivars, such as pot sowing, can be used to control the height of the plants with 0.25% to 0.4% of spray solution over 20 days after germination.

Sunflowers are cross-pollination, which can rely on insects, bees and pollination, artificial artificial pollination when flowering, can improve the seed setting rate. In particular, double-flowered varieties are not easy to bear, and artificial pollination is required for flowering. Pollination time from 9 am to 11 am every day, generally pollinating 2 or 3 times.

Flowering control using pruning or sowing at the wrong time can extend the flowering period.

The length of the ornamental sunflower growth period varies depending on the variety, sowing date and cultivation conditions, and the sowing date can be determined according to the viewing time. From March onwards, sowing is conducted every 20 days. The last time the seeds are sown at the beginning of May, the flowering period is appropriately extended, the plant growth potential is relatively more prosperous, and the flower quality is better.

The use of pruning to extend the flowering period will allow ornamental sunflower cut flowers to be available from late June to early September. According to the growth potential of plants, chase fertilizing materials, timely removal of dense branches, weak branches, bottom leaves and small buds, retaining 1 flower and 1 bud, so that the flowers develop large and full.

If you want to extend the flowering period by one month, you can trim and hit the tip once at the end of May, leave 2-3 leaves to the tip, remove the axillary buds at the base, and trigger the side branches; add fertilizer and water, and cultivating loose soil 1 or 2 times It can bloom in July-August.

If you want to extend the flowering period by 2 months, perform the second wiper in mid-June. The specific method is: wipe the head at the height of 3 to 5 cm after the tip is removed for the first time, remove the axillary buds, weak branches, and dense leaves of the base, and keep the thick branches. Apply liquid fertilizer once a week. . It can bloom from August to September.

Diseases and pests control the incidence of sunflower pests and diseases is low, the main diseases are powdery mildew, black spot, bacterial leaf spot, rust (prevailing in high humidity period) and stalk rot. It can be prevented by disinfecting the substrate, proper watering, increasing air circulation, and intermittently spraying protective fungicides. After the illness, the diseased leaves and stubbles were removed and burned in a concentrated manner; at the initial stage of disease, 50% thiophanate-methyl WP could be sprayed with 500 times liquid or with equal amount of Bordeaux mixture.

The harmful pests of sunflower are locusts, aphids, red spiders, and scarabs, which can be sprayed and sprayed with 40% omethoate EC 1000 times and 73% GEA EC 1500 times.

Cut flowers harvesting

When the outer ray flowers open, they can be harvested. The vase life in water or fresh-keeping liquid is 6-8 days in summer and 10-15 days in winter. Generally, the leaves are removed in the harvesting package, and it is advisable to leave one leaf at the top. Cut flowers can be stored at 2°C to 5°C for about 1 week.

Ornamental sunflower cut flower branch length to reach 40cm or more. The flowering period began in late June. Branches with a length of 60-70 cm were harvested and pretreated. Then 10 bundles were bundled. The flower heads were wrapped in soft paper and put on the market.