Key points of cultivation techniques for planting eight Immortals

Hydrangea, also known as Hydrangea, Saxifragaceae is a deciduous shrub, green leaves, bright colors, long viewing period, deeply loved by people.

Plant characteristics Baxian flower is native to the Yangtze River Basin and southern provinces in China, with a natural plant height of 1 to 2 meters and a potted plant height of 30 to 50 centimeters. Leaves opposite, Obovate or elliptic, margin serrate. Corymbose inflorescences terminal, 20 cm in diam., subglobose, sexual flowers small, asexual flowers many and large. The flower color is changeable, white at the beginning, turning blue or pink gradually, the natural flowering period is from May to July.

Ecological habit Baxian prefers warm and humid environment, the suitable temperature for growth is from 18 ℃ to 28 ℃, and not less than 5 ℃ in winter. The light should be half overcast, and the leaves will be burned and crimped if they are too strong. Like loose and fertile soil, water demand is large, but avoid stagnant water, strong resistance to harmful gases such as sulfur dioxide.

Common cultivated variety V.hortensica: all the flowers are sterile and the sepals are ovate. Blue-edged Immortals (V.coerulea Wils): flowers bisexual, dark blue, with blue or white marginal flowers. V.otaksa Bailey: sterile flowers, large inflorescences, up to 20 cm in diameter, thick leaves, globose inflorescences, blue or light red, mostly used in gardens. Honeysuckle (V.maculata Wils): it is divided into two kinds: fertile and infertile, with narrow leaves and white edges, used for ornamental leaves.

Propagation method Baxian flower can be propagated by means of ramet, striping, cuttage and so on.

Cuttings can be carried out all year round in the greenhouse. Generally from May to June, combined with early spring pruning and post-anthesis plastic surgery. Select semi-lignified and pest-free branches, each section 10 to 15 cm long, retaining 2 to 3 nodes and 1 to 2 leaves at the top, and insert them in a seedbed with river sand or vermiculite as substrate to shade properly. Keep the substrate moist, the air humidity above 80%, and begin to take root in about 18 days. After that, the frequency of water spraying was gradually reduced and the light was increased, and it could be transplanted in about 1 month.

Cultivation and management of planting cuttings should be put into pot in time after rooting. Baxianhua prefers loose, fertile and well-drained soil. It is usually prepared with rotten leaf soil, garden soil and organic fertilizer at the ratio of 4 ∶ 4 ∶ 2. Grass carbon, perlite and organic fertilizer should be prepared at the ratio of 6 ∶ 2 ∶ 2 for large-scale production and thoroughly sterilized before use.

Fertilize eight immortal flowers like fertilizer, generally every half a month to pursue organic fertilizer. There is more nitrogen fertilizer in the early growth stage, and more phosphorus and potassium fertilizer in the flower bud differentiation and bud formation stage. 0.1% to 0.2% potassium dihydrogen phosphate can also be sprayed on the leaves for 2 to 3 times, and the fertilization can be stopped after the flower buds are transparent.

The transpiration of the leaves of the watered eight Immortals is very large, so it must be watered in time, even if the lack of water for a short time wilts, it can also cause the leaf margin to dry up and the flowers to die. Especially in summer, it is necessary to shade and cool down to reduce transpiration and maintain more than 60% air humidity. In addition, the flower color of Baxian flower is usually blue in acidic environment and red in alkaline environment, which is affected by soil pH value. Therefore, the pH value of the water should be determined according to the desired color.

The temperature of Baxian flower is not tolerant to high temperature, and the temperature is required to be between 15 ℃ and 25 ℃. The high temperature will dilute the color of the dwarf flower and reduce the quality. After the flower bud is colored, the temperature is kept at 10 ℃ to 12 ℃ to improve the flower color and keep it fresh.

The eight Immortals are resistant to shade, and direct sunlight will cause sunburn, so shade is needed. Usually 60% shading is needed during the growing period, and the inflorescence should also be shaded properly after the color is transparent, so as not to fade and lose its luster.

Pruned Baxian flower has strong germination ability, and many vegetative branches will germinate at the base of the plant. in order to reduce nutrition loss, it should be erased in time. If the old branch needs to be replaced, a robust vegetative branch can be selected as the reserve branch. Cut it short in time after anthesis and retain 2 or 3 strong buds to promote new shoots.

In order to make the eight Immortals bloom during the Spring Festival, the robust plants of 3 to 5 years old can be selected. After 14 days of low temperature treatment of 2 ℃ to 4 ℃, they were moved into the greenhouse for heating, kept for 10 ℃ to 20 ℃, and blossomed in 50 to 60 days. Pay attention to regular ventilation, maintain good light conditions and high air humidity, and apply organic liquid fertilizer once a month until flowering.