Key Field Management Techniques for Tree Peonies Before and After Flowering
The tree peony (Latin scientific name: Paeonia suffruticosa Andr.) is a plant in the Ranunculaceae family and the genus Paeonia, and is a perennial deciduous small shrub. Its flowers are brilliantly colored, jade-like in beauty and pearl-like in fragrance, elegant and unrestrained, and magnificent, and it has long enjoyed the reputation of “king of flowers”. Among cultivated types, it can be divided into more than a hundred varieties mainly according to flower color. ”There are many varieties of tree peony and also many colors, with yellow, green, flesh red, deep red and silver red being considered superior, and yellow and green especially prized. Tree peony flowers are large and fragrant, hence they also have the name “national beauty and heavenly fragrance”. Field management of tree peonies before and after flowering is very important, so how exactly should management be carried out?
The pre-flowering period is from February to April. During this time the temperature gradually rises, and after a winter of dormancy, the tree peony gradually resumes its growing state. New branches grow, flower buds develop, and sprouting shoots grow, full of vitality. At the same time, field weeds also gradually grow. This period can be called the sprint stage before flowering, and the work must be done carefully. The key technical points are as follows:
Remove sprouting shoots, commonly known as peeling off “soil buds”. The buds sent out from the roots of the tree peony are called “soil buds”. Apart from retaining a certain number of soil buds when old branches need renewing or when division propagation is needed, all the rest should be peeled off, so as to avoid making the plant cumbersome and messy, affecting ventilation and light penetration, and competing with the main branches for water and nutrients. Soil buds should be peeled off early rather than late, that is, when the soil buds first emerge or have not yet emerged in early spring, scrape away the surface soil at the root zone and peel them off, so as to avoid consuming the mother plant's nutrients and affecting flowering.
Apply pre-flowering fertilizer. During this period the rapid extension of branches, the rapid expansion of leaves and the rapid swelling of flower buds all require a sufficient supply of nutrients. Therefore, this topdressing should be based mainly on quick-acting fertilizers, combined with phosphate fertilizer, with a nitrogen, phosphorus and potassium ratio of 2:2:1 or 2:1:1, to promote large flowers and bright colors. Fertilization should be carried out in early March, at about 15 kg per mu, and fertilization should be combined with watering. The nutrients in any fertilizer can only be absorbed and used by plants after dissolving in water, so every subsequent fertilization should also be combined with watering.
Hoeing weeds. Besides removing weeds, hoeing also has the effects of preventing drought and preserving soil moisture, raising soil temperature and promoting early sprouting. The hoeing depth should be about 10 cm, and the soil should be hoed finely, with no unworked patches left.
Field management after flowering
From May to September, this period is right in summer and is a key period for the nutritional accumulation and flower bud differentiation of tree peony growth and development, and is also a period of damage from pests, diseases, weeds and drought or waterlogging. Only by effectively strengthening field management can the tree peony grow robustly and develop well, so that in the following year it will have more and larger flowers with brilliant colors and fragrant blooms. The management measures are mainly “two protections and two promotions”, namely protecting leaves and protecting roots, and promoting growth and promoting flower bud differentiation. The main techniques are as follows:
Scientific fertilization. There is a saying about tree peony flowering that it “would rather give up its life than give up its flowers”. Tree peony flowers are large and have many petals, and they are terminal flowers, so flowering consumes a lot of nutrients. Therefore, fertilization after flowering must be timely, at the latest no later than mid-May, to ensure sufficient nutrients after flower bud differentiation. Farmyard manure or decomposed cake fertilizer should be used mainly, applied at about 100 kg per mu, and watered promptly after application. Where conditions permit, foliar topdressing can also be used at the same time, such as spraying 0.2%-0.5% potassium dihydrogen phosphate, Shishibao or other microelement fertilizers.
Prevent and control pests and diseases. In summer, high temperature and high humidity make pest and disease damage relatively serious, mainly leaf diseases, feeding pests and root diseases. In preventing and controlling pests and diseases, the principle of giving priority to prevention and combining prevention with control must be adhered to. The specific measures are:
1) Spray foliar protective agents. About two weeks after flowering, spray 0.5% lime equivalent Bordeaux mixture on the leaves to prevent pathogenic bacteria from attacking the leaves. Generally the efficacy can last about two weeks, and it can be sprayed 2-3 times in succession.
2) Spray fungicides. In July-August, choose fungicides such as thiophanate-methyl, carbendazim, chlorothalonil and triadimefon and spray 3-4 times, generally once every 7-10 days.
3) Insecticide. Combined with fungicide spraying, insecticides such as pyrethroid insecticides and omethoate can be added to the spray liquid to control feeding pests.
4) Prevent and control root diseases. In recent years, root rot and termite damage have mainly been found to be serious. The control method is to make 2-4 holes in the soil around the roots of the tree peony and place agents such as aluminum phosphide in the holes to kill pests and diseases.
Intertillage and weeding. Summer is the peak season for weed growth. Weeds not only compete with tree peonies for water and nutrients, but weed overgrowth also makes the field excessively dense, reducing ventilation and light penetration, which leads to more serious pest and disease damage, weakened photosynthesis, and can also affect flower bud differentiation. Generally, intertillage is needed 5-6 times in summer, removing weeds as soon as they appear and keeping the field free of weeds. Intertillage can both remove weeds and preserve soil moisture and dissipate dampness. In tree peony plots with good drainage, the method of spreading dry grass between plants and rows can also be used to inhibit weed growth and at the same time play a role in preserving soil moisture and lowering temperature.
Shaping and pruning. The tree peony “grows one chi and retreats seven cun”. The dried and withered branches remaining on the upper part of the flower base after flowering are very long and should be cut off in time. In addition, injured branches, diseased branches and excess lateral branches on the main trunk should also be cut off in time. The purpose is to keep the plant with balanced and moderate branches and an attractive, well-proportioned plant shape, maintain a growth balance between the aboveground and underground parts, provide ventilation and light penetration, and concentrate nutrients to promote root growth, plump flower buds and abundant flowering. Pruning of lateral branches has relatively high technical requirements, and pruning must be reasonable, that is, cutting off overlapping, inward-growing and crossing branches, so that the plant shape is full, with ventilation and light penetration and plump flower buds. The characteristic of apical dominance can also be used by cutting off overly tall terminal buds to cause the lower buds to sprout, which can adjust the balance of the plant clump.