Sichuan Province: high temperature in summer in Nanchong City, Wuxing Garden area, 3000 pots of flowers withered.

In 2013, our city installed an isolation fence in the five-star garden area and planted all kinds of flowers in flower boxes, which attracted bursts of applause from citizens for this move to beautify the urban environment. But recently, a well-known netizen "du Sheng" posted on the Internet, saying that a large area of flowers and plants in the flower box of the urban fence had dried up. "it's a pity to see it. If it is not managed, all the rest may die."

The flower box vegetation withered and died.

On the morning of August 5, the reporter came to the people's Middle Road in the city and saw that all kinds of flowers and plants were planted in the flower boxes of the isolation fence. It is understood that at the beginning, this layout fully took into account the urban heat island effect, not only does not occupy land, but also has the effect of heat insulation and cooling, but also can regulate traffic and beautify the city. But it is a pity that most of the flowers in the flower box have withered. The reporter then came to Shenghuatang Square on City Culture Road to see that most of the plants on the flower bed here were withered and yellow. A similar scene appeared in the flower box of the fence on Renmin South Road.

"the death of these flowers and plants not only goes against the original purpose of planting, but also affects the appearance of the city. I hope that the garden department will strengthen maintenance in time and recover as soon as possible." Ms. Chen, a citizen, said.

Garden department: replanting after the temperature drop

At 03:30 in the afternoon, the reporter telephoned the municipal garden management office, and the relevant person in charge told the reporter that they had received the news that the vegetation in the five-star garden area had withered. "the flowers and plants in the fence were planted around 2013," he said. "the flowers have shallow roots and are not approachable, so it is difficult to absorb water. Nowadays, in hot weather, it is easy to die. "

According to the person in charge, after they received the news that the vegetation in the Wuxing Garden area had withered, they inspected the site and found that about 3000 pots of flowers and plants died. However, due to the high temperature, it is not suitable to replant at present.

"eight sprinklers are used to irrigate urban vegetation every morning and evening, using 200 to 300 tons of water." The relevant person in charge of the municipal garden management office said that they will step up maintenance efforts, and when the temperature drops, they will replant the dead vegetation and give the city a beautiful appearance.

Starry flowers

Star flowers, also known as five-star flowers, are perennial herbs of Rubiaceae. The plant height is 30 to 60 cm, the flower is terminal, the floret is tube-shaped, and the Corolla is star-shaped. The colors are purple, pink, white and so on. It can blossom from spring to autumn, and cuttage culture can be carried out all year round. It likes warm environment and grows well between 25 ℃ and 30 ℃.

Ornamental characteristics and propagation methods of double winter cherry blossoms

Double winter cherry blossom is a cherry plant of Rosaceae, which has many of the same morphological characteristics as winter cherry blossom. it is an endemic native tree species in Heqing County, Dali Prefecture, Yunnan Province. Compared with winter cherry blossoms, double winter cherry blossoms have many flowers, many petals, bright colors and long flowering period. it is an excellent native tree species with better ornamental characteristics than winter cherry blossoms.

1 double winter cherry blossom overview

1.1 morphological characteristics

Double winter cherry blossoms are deciduous trees, up to 5-18m high. Simple leaves alternate, ovate-lanceolate or long elliptic, margin sharply serrate, umbels, 3-9 flowers clustered, growing in leaf axils, miniature inflorescences, calyx tube obconical, calyx lobes shorter than calyx tube, style glabrous, double flowers, about 5-23 petals, rose red, glossy There are a large number of flowers, flowering first and then leaves, flowering from December of each year to early February of the following year, the fruit is nearly ovoid and purplish black after maturity from April to May.

1.2 Geographic distribution and germplasm resources

Double winter cherry blossoms are sporadically distributed in nine natural villages of Xiyi Town, Liuhe Township, Jindun Township and Yunhe Town, Heqing County, with a total of 34535 plants, of which 30500 are seedlings, 3614 are rice diameter 5-10cm, 3614 rice diameter 10-30cm, 2 rice diameter 45-63cm; two century-old mother trees are distributed in Beideng Village, Xiyi Town and Wuxing Village, Liuhe Township. Seize the opportunity of Heqing to establish a provincial garden county, increase the application and promotion of double winter cherry blossoms in landscaping, and transplant about 680 double winter cherry blossoms.

1.3 Ecological habits

The climatic conditions of the suitable growing area are average annual temperature of 14 ℃-16 ℃, annual rainfall of 850-970mm, elevation of 2200-2300 m, and fertile loam with good drainage. The florescence and petal number of double winter cherry blossoms are closely related to annual average temperature, light, nutrients and tree potential. If the average temperature is high, the florescence will be earlier, and if the nutrients are sufficient and the growth is strong, the flowers will have more petals and colorful flowers, on the contrary, the flowers will grow poorly, and the petals will be few and the flowers will become pale. Due to the imbalance of nutrient supply, the number of petals of double winter cherry blossoms in the same plant is different. The petals that bloom ahead of time can reach 15-23 petals, while those that bloom later only have 5 petals.

1.4 Reproductive methods

Double winter cherry blossoms are usually propagated by seeds, and after the seedlings grow up, two kinds of variation will occur in some seedlings through flowering observation: one is that the number of petals decreases, the flower color becomes lighter, and the flower color is between rose and pink; second, the petals and flower color are directly consistent with the winter cherry blossoms, which shows that the seed genetic stability of double winter cherry blossoms is poor. In order to stabilize the ornamental characteristics of double winter cherry blossoms and facilitate their popularization and application in landscaping, it is suggested that grafting should be adopted to ensure the ornamental value of double winter cherry blossoms.

1.5 ornamental characteristics

1.5.1 Flower

The flower is the most ornamental part of the double winter cherry blossom. each flower has about 5-23 petals, double, rose red, flowers gather, flowering from December of each year to early February of the next year, the whole tree is in full bloom like rosy clouds, bright, very beautiful and magnificent, a touch of beautiful scenery in winter, giving people a warm feeling like spring. Therefore, locals commonly call it "Xiaoyangchun".

1.5.2 florescence

Double winter cherry blossoms have the most potential for garden application. Double winter cherry blossoms last for about 15-20 days, which is the transition between winter cherry blossoms and Yunnan cherry blossoms, which can fill the middle gap between winter cherry blossoms and Yunnan cherry blossoms. it can effectively improve the ornamental value of outdoor garden landscape.

1.5.3 leaves

Double winter cherry blossoms are rich in leaf color. Their leaves are deep purplish red at first, yellowish green after extension and maturity, and turn yellow in autumn. Therefore, double winter cherry blossoms are a typical tree species with spring and autumn leaves with obvious seasonal changes.

1.5.4 Fruit

Double winter cherry blossoms enter the fruiting stage after blooming in mid-late February. The fruit is mature at the end of April and the beginning of May. The fruit is nearly ovoid and purplish black. The fruit is green from the beginning to the purplish black when it is ripe, with many gradual changes in the middle, which is also a unique landscape.

In short, double winter cherry blossoms are not only treasures for viewing flowers in winter, but also a rare garden plant for viewing both fruits and leaves.

2Landscape application

Double winter cherry blossoms have a wide application prospect in gardens because of their bright colors, unique petals and rich leaves. In landscaping, planting forms such as isolated planting, row planting, cluster planting, group planting and so on are often adopted.

2.1 isolated planting

Double winter cherry blossom is a fast-growing tree species with tall and straight tree body, luxuriant branches, firm posture, gorgeous and complex flowers when blooming, and rich changes in leaf season, so it is a rare variety of winter flowering, so whether it is planted alone in the courtyard, unit, community, or alone on the hillside, lakeside or stream, it can attract people's attention when it blossoms in winter and become the center of vision and landscape.

2.2 planting

Double winter cherry blossoms with luxuriant branches and shady trees in summer; full of flowers in winter, full of spring, high branching point, rapid growth, strong stress resistance, very suitable for street trees. At present, double winter cherry blossoms are planted on both sides of Chaoxia Road and Gushan Road in Heqing. Due to the same flowering period, they bloom at the same time when they bloom in winter, forming a beautiful scenery. When the flowers fall, the petals dance and stroll under them, just like a fairyland. As double winter cherry blossom is more precious than winter cherry blossom, it is rare to use it as a "cherry blossom road", but with the promotion and application of double winter cherry blossom, it is believed that it will be widely used in the planting of urban street trees in the future.

2.3 Cluster planting

In the street green space and square, double winter cherry blossoms can be planted with 2-5 plants, and can be configured with the surrounding evergreen tree species such as camphor, cedar, magnolia and so on, to fully experience the beauty of "a touch of red in the green trees".

2.4 Group planting

[Jishan Huayao] in some theme parks, double winter cherry blossoms are mixed with other cherry blossom varieties with different flowering periods, colors and petals, which can not only prolong the flowering period, but also maintain the diversity of varieties, and form clumps when they bloom. Layers, clusters, pieces of gorgeous cherry blossom beauty, people travel among them, let people experience the beauty of being placed in the sea of flowers. For example, Heqing Cherry Blossom Park uses 18 cherry blossoms, including double winter cherry blossoms, winter cherry blossoms, Yunnan cherry blossoms, Japanese morning cherry blossoms and evening cherry blossoms, to create a cherry blossom theme park composed of Cherry Blossom Valley, Cherry Blossom Sea and hundred Sakura Garden. Cherry Blossom Park can not only fully reflect the group landscape effect of cherry blossoms, but also serve as a base for popular science education of cherry blossoms, and can also be used as a gene bank for double winter cherry germplasm resources, creating good conditions for garden scientific research.