Cultivation techniques of Primula

Primroses (primulaspp), also known as primroses, New year flowers. Primulaceae, Primulaceae, widely cultivated in the world, has developed rapidly in recent years, and has become an important garden flower. Flowering in early spring is an important feature of this genus.

(1) morphological characteristics and types

Perennial root herbs, but most of them are cultivated as annual or biennial flowers. The plant is low, the leaves are all basal, forming rosette-like foliage, and the flowers are red, yellow, orange, blue, purple and white, arranged in umbels on the buds, racemes and globose capsules. There are many kinds of primroses, the most common of which are:

1. Primrose (p.malacoides) is native to Yungui and has a wide variety of horticulture. It is an excellent winter potted flower in cold greenhouse.

2. P.obconica, also known as primrose, originates from southwest China. Horticultural varieties are rich in color and bright in color, both single and double. It is a cold room winter early spring potted flower, which is widely planted all over the world. It blossoms continuously in Kunming all year round, so it is also called four Seasons primrose.

3. Tibetan primrose (p.sinensis), also known as Chinese primrose, originated in Sichuan, Hubei and other places. The original rose purple flowers, horticultural varieties with larger flower shape, with peach red, orange, crimson, blue and white, are important cold room winter and spring potted flowers.

4. P.vulgaris (p.acaulis) is often used in business to refer to horticulture changing species, originating from Western and Southern Europe. Modern horticultural varieties have sleeve petals in addition to single and double ones. The flower color is rich, the sex is hardy, can overwinter in the open field in Western Europe, is an excellent variety of flower bed in early spring, can also be potted.

(2) Ecological habits

Primula is a typical warm temperate plant. Most of the species are distributed in high latitude, low altitude or low latitude and high altitude. They prefer cool, humic environment and humus-rich soil. They are not resistant to high temperature and strong direct sunlight, and most of them are not resistant to cold.

Primroses which are generally used as potted flowers in cold greenhouse, such as primrose and Tibetan primroses, should be cultivated in neutral soil. Not resistant to frost, early flowering. As a flower bed arrangement in the open field, Primula is suitable for growing in shady slope or semi-shady environment, and likes the soil with good drainage and rich in humus.

(3) methods of reproduction

Primroses are mainly propagated by seeds, and special horticultural varieties also use ramet or tillering methods.

The life span of seeds is generally short, so it is best to sow them immediately after harvest, or to store them at dry and low temperatures. Sowing seeds in sowing boxes or shallow pots. Because the seeds are small, they can not be covered with soil after sowing. Seeds need light to germinate and like to be moist, so they need to be covered with glass and covered with a newspaper, or put in a semi-shaded place. It sprouted in 10 to 28 days. When the suitable temperature 15c~21c is more than 25c, the germination rate decreases obviously, so the midsummer season should be avoided. The sowing period is determined according to the required flowering time. If it blossoms in winter in a cold greenhouse, it can be sown in late spring; if it blossoms in early spring, it can be sown in early autumn. Flowers are used in open-field flower beds in spring, and they can also be sown in early autumn.

Tillering is usually carried out in autumn.

(4) cultivation techniques

Primula cultivation management well is not difficult, as greenhouse pot flower species, from sowing to 12 cm pot listing, about 160 days. If sown in July, it can blossom at the beginning of the year. To avoid hot weather, sow seeds in August or blossom in January. The first transplant in a shallow basin or wooden box, the plant distance is about 2 cm, or directly on the 8 cm small basin, the basin soil should not be acidic, and then directly on the 12 cm basin. Planting depth should be moderate, too deep and easy to rot roots, too shallow easy to lodge. Fertilizers must be applied regularly. The reason for the loss of green leaves, in addition to the acidity of the basin soil, may be too wet or poor drainage. Not only should the sun be shaded in summer, but also shade should be given when the sun is strong in winter to ensure bright colors.

For hardy species, when overwintering in the open field to the north of the Yangtze River, leeward conditions should be provided and slight protection should be given to ensure safety. Sowing in August, potted seedlings overwinter in a cold bed, and can blossom and appear on the market from February to April.

The seedlings are transplanted into the pot, and the flowerpot is generally limited to 12 cm ~ 16 cm. The 2-year-old plant can be enlarged properly. Pay attention to ventilation during the summer, give semi-overcast and prevent showers, spray, scaffolding and ground sprinkling and other measures to cool down. The lowest indoor night temperature in winter is controlled at about 5c, which should not be too high. However, as potted flowers, if sowing too late (October), the overwintering temperature should be raised to 10c in order to accelerate growth and ensure timely flowering in next spring.