What are the precautions for growing peonies?

Peony flowers are large and richly colored. They are highly cold-hardy and can overwinter outdoors in most parts of northern China. However, they are less heat-tolerant and stop growing in summer. They like sunlight but can also grow and bloom in light shade. They like moisture but fear waterlogging, and are best grown in deep, fertile, moist, and well-drained sandy loam. Low-lying saline-alkali land is not suitable for planting. The key cultivation points for peonies are as follows:

1. The planting site should be chosen in a wind-sheltered, sunny place with deep soil and high, dry terrain. Before planting, deep plowing is needed, with a plowing depth of more than 30 cm, and fully decomposed organic fertilizer, bone meal, and a small amount of insecticide should be applied; then plow again, and cover with a thin layer of soil on top to avoid direct contact between the roots and the fertilizer, which can cause root rot.

2. Place the peony into the hole so that the root system spreads out and straightens. Planting should not be too deep or too shallow; generally, covering the buds with 2-3 cm of soil is appropriate. After covering with soil, gently press the soil firm and water thoroughly after planting. Shallow cultivation should be carried out the next evening to keep the soil well aerated.

3. In areas with severe winter cold, after winter begins, mound 20-25 cm of soil over the planting holes to help them overwinter safely. In the spring of the following year, after the soil thaws, promptly remove the mounded soil. When new buds sprout in spring, fertilize and water, and carry out cultivation to conserve soil moisture.

Peony

I. Watering

Planting is generally carried out from late August to September; earlier is better than later, and no later than late October, otherwise the peony buds will have already developed new roots, which will affect the yield and quality of the peonies. To ensure uniform emergence and easy management, the peony buds should be graded by size and planted in holes. The row spacing and plant spacing for planting are 50 cm x 30 cm, with holes 12 cm deep and 20 cm in diameter; first pour enough water into the hole, and after the water seeps down, spread 4 cm of decomposed barnyard manure at the bottom of the hole, cover it with 4 cm of soil, press firm, then place the peony buds in the middle of the hole with the bud tips facing up, placing 1-2 peony buds per hole. After planting, mound soil 10-15 cm high around each hole. Before overwintering, water thoroughly with anti-freezing water.

II. Soil

Drainage should be good. Peonies like a cool climate and are suitable for cultivation from China's temperate to subtropical regions. They have the characteristics of sprouting in spring and rooting in autumn. In summer, during hot and scorching seasons, the plants enter a semi-dormant state. They prefer fertile, loose, well-drained sandy loam and avoid saline-alkali soil. Because peonies have fleshy roots, they are drought-tolerant but fear water accumulation. If the soil is compacted and water accumulates, it can easily cause the fleshy roots of peonies to rot, so low-lying land and saline-alkali land are both unsuitable for cultivation.

Therefore, for ground planting, choose a cool place with ample sunlight, and for potted planting, avoid excessive watering. Throughout the dormant period from the beginning of winter to early spring, the soil should remain moist, not too dry, but drainage must be unobstructed, and water accumulation must be avoided; otherwise, the underground tuberous roots can easily rot and die.

III. Fertilizer and Water

Peonies are fertilizer-loving crops. In addition to applying sufficient base fertilizer, starting from the second year after planting, topdressing is needed 3 times each year; the 1st time is after cultivation and weeding in March, applying 1500---2000 kg of human and livestock manure water per mu; the 2nd and 3rd times are in May and July respectively, each time applying 1500 kg of human and livestock manure water and 25-30 kg of cake fertilizer per mu, or 40--60 kg of ternary compound fertilizer. Peonies like dry conditions and fear waterlogging, so they generally do not need watering, only one thorough irrigation during severe drought. In rainy seasons, ditches must be cleared for drainage; otherwise, after 6 hours of flooding, the roots will rot and the entire plant will wither and die.

Control of Common Diseases in Protected Cultivation of Peonies

Peony is a traditional famous flower of China and is also one of the flowers with the longest cultivation history. Peonies are rich in varieties, with different flower colors and flower forms, but their flowering period is relatively concentrated. In order to make better use of this ornamental plant resource, people have now begun to study and use protected cultivation techniques to prolong the ornamental period of peonies and expand their planting and application range. A key part of protected cultivation of peonies is the prevention and control of pests and diseases, especially integrated disease control. Due to the limitations of protected facilities, ventilation and light are generally not as good as in the natural environment, so some diseases may occur. The common peony diseases in protected cultivation are not as numerous as those in natural planting, but the degree of damage is more severe. This article introduces the common diseases and their control methods in protected cultivation of peonies as follows:

Gray Mold

Symptoms There are two types of symptoms. One type is leaf spots that are nearly circular or irregular in shape, mostly occurring at leaf tips and leaf margins, brown or purplish brown, with irregular concentric rings. When air humidity is too high, gray mold-like substances grow, namely the pathogen's conidia; stem spots are brown and soft-rot-like. When the stem base is damaged, the plant may collapse. When flower parts are damaged, they turn brown, become soft-rotten, and produce gray mold-like substances; sometimes black granular sclerotia are produced at the diseased spots. The second type is brown spots on leaf margins, causing brown concentric-ring-like waviness and wrinkling along the leaf edges, soft rot of petioles and flower stalks, and rotting of the outer skin. When flower stalks are damaged, seed maturation is affected.

Occurrence Pattern The fungus overwinters in the soil as sclerotia; high temperature and high humidity in protected cultivation are favorable for the mass formation and spread of conidia; excessive nitrogen fertilizer application, overly dense planting, high humidity, and insufficient light all make plants more susceptible to infection by the pathogen; when peonies are forced in greenhouses, this disease often causes flower buds to shrink and rot. In protected cultivation of peonies, this disease mostly occurs in the early stage of leaf expansion.

Control Methods 1) Before planting, soak the plants in a 300-fold solution of 70% wettable mancozeb powder for 10—15 minutes. (2) For treatment of the cultivation substrate, mix 70% quintozene wettable powder and 70% mancozeb in equal amounts uniformly, using 8—10 grams per square meter. (3) Pay attention to ventilation and light transmission, apply nitrogen fertilizer in appropriate amounts, avoid excessive irrigation during the leaf expansion period, and remove diseased leaves and diseased plants at any time. (4) When plants develop the disease, spray 80% zineb 800—1000-fold solution, 70% thiophanate-methyl 1000-fold solution, 50% procymidone or iprodione wettable powder 1500-fold solution. In greenhouses, in the early stage of disease occurrence, smoke methods can be used, selecting 45% chlorothalonil smoke agent, 10% procymidone smoke agent, 15% kemeiling smoke agent, etc., which saves labor and does not increase humidity.