why the paeoniarockii grafted seedlings cut off the remaining flowers after flowering

 In mid-May, the paeoniarockii has basically finished blooming. Post-flowering management is very important and will affect the flowering and growth effects of the next year.

The paeoniarockii grafted seedlings cut off the remaining flowers after flowering, mainly based on the following key reasons:

1. Reduce nutrient consumption and promote plant growth

- Peony flowering requires a lot of nutrients, especially in the initial stage of root system and rootstock fusion of grafted seedlings, the nutrient reserves of the plant are relatively limited. Timely cutting off the remaining flowers can prevent nutrients from being used for seeding or maintaining flowers, and instead concentrate energy on root system development, new bud differentiation and branch and leaf growth, accumulating more sufficient nutrients for flowering next year.

2. Prevent the breeding of pests and diseases

- If the withered flowers remain on the branches for a long time, they are prone to breeding pathogens such as mold and gray mold due to moisture or rot, and may also attract pests. Cutting off the remaining flowers can reduce the risk of plant infection and maintain overall health.

3. Ensure the survival and adaptation of grafted seedlings

- Grafted seedlings need to focus resources on the healing and adaptation of rootstock and scion in the early stage. Retaining residual flowers may increase the burden on the plant and affect the healing speed and survival rate of the grafted part. Cutting flowers helps the plant to smoothly pass the critical growth period.

4. Promote flower bud differentiation and improve the quality of flowering next year

Flower bud differentiation of peony usually occurs after flowering. Cutting off residual flowers can reduce nutrient diversion, enable the plant to photosynthesize more efficiently, and promote the formation of new flower buds, thereby ensuring larger and more luxuriant flowers next year.

Pruning operation suggestions:

Timing: Prune immediately when the flowers begin to wither and the petals wilt significantly, and avoid delay.

Method: Use sterilized scissors to cut flatly from the base of the pedicel (about 1-2 cm below the calyx) to avoid damaging the new buds.

Subsequent care: After pruning, add appropriate amounts of phosphorus and potassium fertilizers to enhance the resistance of the plant; keep the soil moist but not too wet to avoid root rot.

Through scientific pruning, purple-spotted peony grafted seedlings can establish a strong plant structure more quickly, laying a solid foundation for their future ornamental value.

Please master these planting techniques and you can also make the rare plant paeoniarockii bloom beautiful flowers

 The daily management of Paeonia rockii needs to be combined with its growth habits and environmental needs. Detailed management guidelines are as follows:

Environment and soil management

Lighting requirements

need 6 hours or more of direct sunlight a day, and adequate shade (especially for seedlings) in high summer temperatures.

avoid long-term shade, which will result in reduced flowering and emaciated plants.

2. Soil conditions

Loose breathable, good drainage of sandy loam is best, avoid clay heavy soil or water.

soil pH should be neutral or slightly alkaline (6.5-7.5) .

Management of water and fertilizer

1. The principle of grade watering

Spring germination: keep the soil moist to avoid drought affecting flower bud differentiation.

Summer: Morning and evening watering, avoid high temperature at noon, to prevent burning roots.

Autumn: reduce the frequency of watering and promote lignification of branches for overwintering.

Winter dormant period: basically cut off water, keep the soil slightly dry.

2. Fertilizer tips

Spring (before germination) : apply NPK balanced compound fertilizer (such as 15-15-15) to promote the growth of new shoots.

Bud Stage: increase phosphorus and potassium (such as Monopotassium phosphate) to improve flowering quality.

After flowering: topdress rotten organic fertilizer (such as bone meal, cake fertilizer) to add nutrients.

Autumn (September-october) : burying and applying decomposed organic fertilizer to enhance the ability of overwintering and cold resistance.

Pruning and shaping

1. Pruning after flowering

Cut off the remnant flowers in time to avoid the consumption of nutrients and keep the leaves for photosynthesis.

remove dead and diseased branches and keep them well ventilated.

2. Shaping and pruning (winter)

During the dormant period, the dense branches and cross branches are pruned, and the strong main branches are retained.

Tree peony can retain 3-5 main branches, forming a natural opening of the plant type.

The pest control

1. Common diseases

Gray mold: rainy season prone to use 50% carbendazim 800 times the liquid spray.

Root rot: avoid standing water and irrigate roots with metalaxyl at the beginning of the disease.

2. Common pests

Aphids: spray imidacloprid or soapy water.

Spider mites: hot and dry, use Avermectin to control them.

Management of overwintering

1. The north

– pour“Sealed water” before winter and cover the roots with straw or earth (10-15 cm thick) to protect against the cold.

– young plant can be wrapped with non-woven cloth.

2. The south

– In general, no special protection is required, but defoliation should be cleaned to reduce the growth of pathogens.

Propagation and transplanting

1. Ramet propagation

The best time is autumn (September-october) , selecting 3-4 years old mother plant, keeping complete root system.

2. Main points of transplanting

– when transplanting with soil ball, to avoid root injury, after planting watering and shade seedlings.

Points to note

Avoid continuous cropping, more than 3 years between plantings in the same plot.

Avoid raining during the flowering period to prolong the life of flowers.

Loosen the soil and weed regularly to keep the soil well ventilated

Spring Care Guide for Tree Peony (Paeonia rockii): Ensuring Vigorous Growth and Spectacular Blooms

 Tree Peony (Paeonia rockii), renowned for its striking purple-blotched petals and intoxicating fragrance, is a prized ornamental plant. Spring is a critical period for bud development, shoot growth, and flower formation. Follow these expert management practices to ensure healthy growth and breathtaking blooms.

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1. Early Spring Pruning and Garden Cleanup

• Remove Dead/Damaged Branches
• Prune frost-damaged, diseased, or crossing branches when temperatures stabilize above 5°C (late March in northern regions, late February in southern areas).
• Sterilize pruning tools with alcohol to prevent disease spread.
• Clear Debris
• Rake fallen leaves, weeds, and overwintering pests around the base to reduce disease risk. Lightly dust the soil with lime or sulfur powder for disinfection.

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2. Water and Fertilizer Management

• Early Growth Stage Fertilization
• Timing: Apply when new buds emerge but before leaves fully expand (early April in the north, mid-March in the south).
• Method: Use well-rotted organic fertilizer (e.g., bone meal, compost) mixed with balanced NPK fertilizer (15-10-10). Apply 200–300g per plant in a ring around the root zone, then water thoroughly.
• Bud Development Stage
• Timing: When flower buds begin to swell (late April in the north, early April in the south).
• Method: Foliar spray with 0.2% potassium dihydrogen phosphate solution (2g per 1L water) every 10 days to enhance bud quality.
• Watering Tips
• Keep soil moist but not waterlogged. Water deeply once after pruning, then adjust based on rainfall. Avoid overhead watering to prevent fungal issues.

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3. Pest and Disease Control

• Common Diseases
• Leaf Spot: Spray with 70% mancozeb (800x dilution) at the first sign of brown spots.
• Root Rot: Caused by waterlogging. Remove affected plants, trim rotten roots, soak in carbendazim solution, and replant in well-drained soil.
• Insect Pests
• Aphids/Spider Mites: Control with neem oil or 10% imidacloprid (2000x dilution).
• Grubs: Apply phoxim granules to the soil around roots (follow label instructions).

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4. Wind Protection and Support

• Windbreaks
• In windy areas, install temporary windbreaks (e.g., bamboo stakes or burlap screens) to protect tender shoots and buds.
• Bud Thinning
• Retain 1–2 healthy buds per stem; remove excess buds to concentrate nutrients for larger, showier blooms.
• Staking
• Use soft ties and stakes to support heavy flower stems and prevent drooping.

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5. Frost Protection and Bloom Extension

• Late Frost Prevention
• Cover plants with frost cloth or straw mats if temperatures drop below 0°C after bud break. Spray water early morning to mitigate frost damage.
• Extending Bloom Time
• Provide partial shade during peak bloom (e.g., shade cloth) to slow petal wilting. For potted plants, move to a cool, shaded area.

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6. Post-Bloom Care

• Deadheading
• Remove spent flowers immediately to prevent seed formation and redirect energy to root growth.
• Post-Bloom Fertilization
• Apply a balanced fertilizer (10-10-10 NPK) to replenish nutrients and strengthen roots for next year’s growth.

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7. Regional Considerations

• Arid Northern Climates: Mulch with pine needles or wood chips to retain soil moisture.
• Humid Southern Climates: Ensure excellent drainage; loosen soil after heavy rains to prevent root suffocation.

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Pro Tip: Tree Peonies are deep-rooted—avoid transplanting in spring to minimize root disturbance!

With proper care, your Paeonia rockii will reward you with majestic blooms that embody elegance and resilience.

Common Pests and Diseases of Peony-

Tree Peony, as China’s unique woody flowers, with thousands of years of natural growth and more than 2000 years of artificial cultivation history, widely loved by the people, often found in the garden or landscape. However, in the process of tree peony cultivation, due to weather, soil and management and other reasons, it is easy to appear disease. The infected plants often show the phenomenon of leaf covered with disease spot or edge withered, branches thin and weak, root rot and disfigurement, if the infected plants are not treated in time, the disease will spread in a large scale, which greatly affects the ornamental value and economic value of the tree peony. Therefore, peony disease control is an important part of the cultivation of peony, today to give you a brief introduction of the six major peony disease control.

01Anthrax

Damage parts: stems, petioles and petals and other plant young tissues

Manifestation: the leaf surface will appear small brown spots, when serious into a round or irregular spots can lead to perforation, the affected young leaves will also show the characteristics of shrinkage, curling. After infection, the stem will appear initially reddish brown oblong spots, then will develop into large irregular spots, the middle will appear inconspicuous light gray, the edge of the spot is reddish brown. Infected stems will bend and eventually fold, and young stems will wither and die in a short period of time. The petal and the flower scale can appear bud wither and the deformity flower and so on question, if the occurrence disease is in the rainy and wet season, the surface also can produce the pink spore pile.

High incidence: the pathogen of anthracnose usually overwintering in the form of hyphae in the diseased plant. Conidia will germinate and spread when the temperature is suitable in the second year.

Methods of prevention and Cure:

1 deep turn the soil of peony cultivation, improve the air permeability of soil and the environment of microorganism growth, ensure the root can stretch to grow, absorb sufficient nutrient.

(2) pruning the whole plant in time, removing dead branches and debris, and burying or incinerating them.

3 spraying 75% Mancozeb or Anthrax Thiram 500 times, once every 15 days, continuously spraying 2-3 times.

02 Powdery mildew

Damage parts: leaves and petioles

Manifestation: the peony leaves will form a layer of white powdery spot in the early stage, and the disease spot will appear on both sides of the petiole and leaf surface in the late stage, accompanied by many small black spots, and gradually expand and develop into a large area of disease spot, it can cause whole leaves and stalks to wither and die.

High-incidence period: generally in the rainy and wet season occurs very serious, too dense plants or poor ventilation can also cause peony powdery mildew.

The control methods were as follows:

(1) proper pruning and shaping could be carried out to improve the ventilation and light permeability of the plants and to remove the infected leaves in time. (2) spraying 20% triadimefon WP and strengthening field management, phosphorus and potassium fertilizer could be applied properly, but the amount of nitrogen fertilizer should be strictly controlled to improve the disease resistance of plants.

3 sulphur mixture could be sprayed before sprout in spring, 80% Mancozeb wettable powder or carbendazim could be sprayed at the onset of disease in growing season, once every 15 days and three times continuously.

03Root rot

Damage: Root

Manifestation: the leaves will turn yellow or reddish, some mesophyll will turn yellow, while the growth of some plants on the ground is weak, serious will lead to leaves and branches withered, the whole plant death, the roots of the diseased plants were found to be rotten and dark brown.

High incidence period: the field environment is humid, water accumulation is serious. In addition, the plants which were not transplanted with soil ball during Ramet transplanting were also susceptible to disease.

Prevention and Cure Method: after the soil is deeply turned, carbofuran can be applied, and carbendazim WP can be sprinkled on the base of peony root, every 10 days, to ensure that the medicine can be deep underground.

04 Leaf spot

Damage parts: leaves and shoots

Manifestation: 15 days after flowering, brown spots appear on the abaxial surface of the leaves, the edge of the color is darker, and then developed into an irregular circular spots, all the spots can be connected into one, leading to leaf wither and fall. Infected stems and stalks produce raised lesions, and pathogens can overwinter in stems, leaves, and soil.

High incidence period: generally in the rainy season onset of serious, in high temperature and humid conditions.

Control methods:

1 cut off the infected branches in time before and after the beginning of winter and burn them to ensure that the pathogen was completely eliminated.

2 Bordeaux mixture and thiophanate-methyl were sprayed 3-4 times before the onset of the disease.

05Botrytis cinerea

Damage parts: young plants and peony flowers, stems and leaves and other parts

Manifestation: cause the tree peony seedling lodging and withering, death. The infected parts give birth to gray mold, brown spot also appears on the stem, peony peony seed will be seriously affected when the peduncles encounter this kind of disease.

High incidence: July-august every year, when the weather is wet.

Control methods:

1 new soil transplanting, old soil can be sprayed with pentachloronitrobenzene wettable powder for disinfection treatment.

2 control planting density, ensure timely drainage after ventilation and light permeability.

3 the infected branches, leaves and buds should be cleaned up in time, and the whole plant should be pulled out and destroyed.

4 Bordeaux mixture and thiophanate-methyl solution can be used to prevent and cure the disease.

05 seedling damping-off disease

Damage parts: stem base and whole plant

Manifestation: in the process of seedling raising and germination, seedling damping-off will lead to hypocotyl and leaf rot. The seedlings were infected by the disease after they were unearthed, and the first damage was to the base of the stem. Canker lesions appeared on the affected parts, then changed from light brown to yellow brown, and spread around the whole stem, seeds that have not sprouted can also be infected when the disease is severe. Usually, seedling damping-off is mainly caused by pathogenic fungi of the genus Phytophthora. The disease can be spread by means of agricultural machinery, transplanting and farm manure.

Control methods:

1 select disease-free new soil, do not use diseased field to raise seedlings, but also choose Mancozeb and metalaxyl medicament, evenly mix and spread on the border.

2 in addition, peony seeds should be disinfected in 50 ° C warm water for 20 min, then diluted with pyrazolium and Mancozeb etc.

The key point of planting rockii peony

 The method to planted ROCKII Peony in land or pot are essentially the same, the key points are as follows:

for peony’s root is Intensive, if not careful when planting, the soil is not easily filled into the root of the heart of peony, leading inside of the root can not let the soil infill, the core part is still empty after the seedlings were planted.

Part of roots contact with air so that the root of peony will mildew while growing, mildew will gradually make root rot, poor growth after germination, slowly dying phenomenon appears.

Second, land planted or potted plants are not watered too much. The specific approach is: peony planting immediately after pouring a permeable. After watering interval can not be too short, as long as the soil is kept moist. If the water is too much, soil airtight seedling growth process leaves will yellow and dying.

Third, the fertilization. Fertilizer in the soil can not be too much, especially inorganic fertilizers, too much will hurt the root system, it is best to the seedling leaves Expand, fertilizer spray once every ten days page, but the concentration is not large.

Fourth, to trim. Pruning is an important part of the seedlings were planted seedlings were planted sure to Ruomiao the trimmed. Maintain a 3-5 strains robust branches, so that nutrition can be set to ensure that the main branches vigorous growth, a good start to spend.

Fifth, the light. Peony to hi lighting, nursery stock can not be placed in insufficient light for a long time. Only in the flowering buds fully formed, in order to meet the manual set the flowering period (extended flowering period) may be appropriate shade, generally no more than seven days.

How a seed of Paeonia rockii grows into a tree peony

 Peonies are giants in the peony world. They are tall, fragrant and resistant to cold. The main methods of propagation are grafting and fruiting. How does a seed grow from a seedling to a tree

Choose the full-bodied seed of peonies

1. Before sowing, Soak 300 times of thiophanate-methyl solution for 30 minutes to sterilize, remove and place in a cool place to dry

2. If the area of seedling is large or the condition is allowed, the sowing machine is usually used or the artificial sowing can be adopted. If it is a mechanical sowing, be sure to level the ground to avoid local sowing too deep.

The sowing quantity is 90-100kg/Mu, the sowing depth is 3-5cm, the row distance is 20-25cm, the concrete also has the relations with the local climate and the soil condition.

Every 4 rows is a ridge (bed) covered with a layer of 120 cm plastic film, film is too wide central seedlings easy to rot, not easy to survive.

3. After mulching plastic film covered with grass or a sm

all amount of soil, to increase the temperature, extend the growth time of new roots, is conducive to the next year strong seedlings. Early Spring Peony shoots drill out before the ground, to remove timely plastic film.

The space between small Ridge (bed) and small Ridge (bed) is 40cm, which is convenient for later watering and pipe protection.

4. The seeds of Paeonia rockii germinate after three months and take root in the following spring

It takes at least six months for a seed to be planted and a young tree peony to form. It is this young tree that has been honed into a big tree through decades of continuous growth, to be a giant in the peony kingdom.

 

Why Autumn is one of the best seasons for transplanting peonies

Spring is the season of peony branch

Summer is the dormant period of peony, high temperature season, the above-ground part into the stage of flower bud differentiation and seed development, when the root activity becomes weak, in a semi-dormant state.

After autumn, as the temperature drops, the root system of tree peony begins to grow a second time, it will grow a lot of capillaries, a lot of nutrients in the root bark (mainly secondary phloem) in the accumulation. At this time, the above-ground part of the branches and leaves slowly withered into the dormant period, but the peony root system is still growing to produce new roots. These new fine roots is the most important tree peony transplant, transplant to other places, can adapt to the new environment, quickly take root, so safe over the winter.

What are the benefits of transplanting peony in autumn?

The temperature drops gradually when peony transplanting in autumn, the above-ground branch enters dormancy period, the leaf slowly withers this to the water demand is little, consume nutrient little, this is advantageous to the nutrient balance. Moreover, at this time, the root bark was rich in nutrients, and the ground temperature was relatively high even though the outside temperature had not yet dropped significantly.

The roots of the tree peony were not yet completely dormant, and the root system cut off during transplantation could be healed as soon as possible, and the root system is still growing, constantly producing new roots.

Common diseases and insect pests of tree peony

In the growing process of tree peony and Paeonia lactiflora pall, insect damage will inevitably occur. The peony seedlings with diseases and insect pests often have leaves covered with disease spots or withered edges, branches are thin and weak, roots rot and become incomplete, and in serious cases, they even bloom or not, plant Growth and development slow, but also affect the quality and yield of Root Bark, if not timely control, will also affect other flowers. Therefore, in the cultivation and management of tree peony and Paeonia Lactiflora, it is necessary to know the occurrence regularity and control measures of their common diseases and insect

pests.
1. Gray mold
The disease has a short onset and is spread by wind, causing great harm.
(1) the symptom seedlings appeared Brown watermarked spots at the base, and the seedlings gradually withered and fell down. Infected Leaves Produce Brown, purple-brown water spots, sometimes with irregular whorls, to the tip and leaf margin more. The gray mould layer in the diseased part is a prominent feature of the disease. Botrytis cinerea is a fungal disease.
(2) conditions of onset
The persistent low temperature and humid climate are the main causes of the disease. Spring and the end of flowering period from June to July were the peak period of the disease. Plant clusters are large and dense, and too much nitrogen fertilizer is also susceptible to disease.
(3) prevention and control
Find and remove the diseased parts in time, pull out the diseased plants and destroy them in time, take care not to contaminate the healthy plants, and disinfect the tools that come into contact with the diseased plants in time.
2 In case of disease, chemical control can be carried out: 1% equivalent bordeaux mixture, 70% thiophanate-methyl 1000-fold solution, 65% ZNZ 500-fold solution or 50% ammonium chloride 1000-fold solution are sprayed once every 10-15 days and continuously 2-3 times.
3 strengthen cultivation management, arrange planting density reasonably, remove water in time after rain, and loosen soil to hoe. The newly purchased tree peony seedlings were soaked for 10 ~ 15 minutes in 65% 300-fold solution of daisenxin before continuous cropping was carried out in the serious disease area.
In autumn, the dead branches and leaves were removed, and the diseased buds and leaves were removed in time to reduce the source of infection.
Leaf spot disease

A. Erythema
Red Spot disease also known as leaf spot disease, peony disease less, mainly to harm the peony.
(1) pathogen cladosporium peony: Fungal Diseases.
(2) symptoms
Damage to the leaves, planting strip, flower, seed and other parts. The lesions appeared initially on the upper and lower surfaces of the leaves, Brown, Submycorrhizal, the edge of the lesions was not obvious, when severe, the leaves twisted, dry. Wet and rainy weather can be seen gray-green mold layer, stem and petiole spot long strip, Central Crack, disease department easy to break. When the disease spot on the flower organ is serious, the edge of the petal will be scorched.
(3) conditions of onset
In warm and rainy climate, the diseases will be caused or aggravated by the application of too much nitrogen fertilizer, the planting density is too high, which leads to poor ventilation or the retention of diseased plants. Peak season in spring and summer.
(4) prevention and control
1 clear the disease strain in time, spray 50% CARBENDAZIM 600 times solution or 3 Be sulfur mixture before germination in early spring to kill the plant and above-ground bacteria.
2 when peonies germinated in early spring, spreading thin film on the ground and pressing the edges with Earth pressure can prevent the spread of pathogens and accelerate the decomposition of disease residues.
3 after onset, 160-200 times equivalent Bordeaux mixture can be sprayed once every 10-15 days, or 50% carbendazim 1000 times, 65% thymosin 500-600 times, once every 7-10 days for 3-4 days.
4 strengthen the management of peony seedling cultivation, arrange planting density reasonably, apply nitrogen fertilizer properly, apply compound fertilizer and organic fertilizer more.
5 reduce the source of infection: Spray 3 Be sulfur mixture or 50% CARBENDAZIM 600 times solution in early spring. Autumn thoroughly remove the body of disease and disability.

Alternaria leaf spot
Also known as White Star disease, is a common tree peony disease.
(1) pathogens
1. CERCOSPORA PEONIAE 2
(2) symptoms
The blades are the hardest hit. At the beginning of the leaves appear Pale yellow spots, gradually expanding into a round or nearly round spot, Brown, and visible whorls, scattered above a lot of small points of mold, to the central spot most dense. The lesions near the leaf margin and main vein were semicircular in shape. The whole leaf is scorched when the disease is serious.
(3) conditions of onset
Rainy and humid climate, low-lying and water-accumulating terrain, poor ventilation and light transmission, and high planting density are all suitable to cause the disease, which is the main leaf disease in the late growth period of peony. August to September is the peak period.
(4) prevention and control
1 Chemical Control in growing season: 1% lime equivalent bordeaux mixture, 50% triazolam 800-fold solution or 65% thymosin 500-fold solution were sprayed once in 10-15 days after onset and continuously for 1-2 months.
2 strengthen cultivation management, arrange planting density reasonably, and pay attention to ventilation and light transmission.
3 Prevention of disease and reduction of infection source: Spray 3 Be sulfur mixture or 50% CARBENDAZIM 600 times solution in early spring. Autumn thoroughly remove the body of disease and disability.
C. Ring Spot
Also known as leaf gray spot, peony, peony are harmful, but not as common as the first two, is a fungal disease.
(2) symptoms
A large round or nearly round spot may be formed on the leaf, the diameter of which may be more than 5 mm. There are obvious concentric rings, which are Grayish Brown, and many small black mould spots in the middle are arranged in a wheel shape.
(3) the conditions of disease and its prevention and control
Alternaria leaf spot of tree peony.
Anthracnose of peony
(1) pathogens
A type of anthrax: Fungi IMPERFECTI.
(2) symptoms
Leaf Blade, petiole and neck. After anthesis, a small brown spot appeared on the leaf surface, and gradually expanded, and was hemimycete-shaped, black-brown by the inhibition of leaf veins, to the late middle of the spot into white, Edge red-brown, and split, perforation, spot scattered on a lot of black spots, under moist conditions, the reddish-brown myxomycetes can be seen on the stems and petioles. The infected stems are often twisted, and if the tender stems become diseased, they will soon die. Bud Scales and petal damage often cause bud blight and flower deformity.
(3) conditions of onset
High temperature, rainy, dew, planting density is too large easy to cause the disease.
(4) prevention and control
1 CHEMICAL CONTROL IN GROWING SEASON: spraying 70% thiram 500 times solution, or 1% lime equivalent bordeaux solution, 65% THYSSEN ZINC 500 times solution, once every 10-15 days for 1-2 months.
2 Prevention of disease and reduction of infection source: Spray 3 Be sulfur mixture or 50% CARBENDAZIM 600 times solution in early spring. Autumn thoroughly remove the body of disease and disability.
Root Rot

(1) pathogens
It was mainly fusarium Solani, other fusarium species and Armillaria compound infection.
(2) symptoms
The symptoms of peony and Paeonia lactiflora in spring appear after leaf expansion. The growth of the above-ground part is weak, the leaves are green, yellow and red, and the branches and leaves die when it is serious, if not controlled in time, the whole plant will die. When digging out the diseased plants, the roots were usually black-brown and some of them decayed, and there were traces of Grub gnawing.
(3) conditions of onset
Field seeper and wet environment more disease, continuous cropping land is often a large number of disease. When the pest is serious underground, the wound on the root also makes the germ easy to infect. Tree Peony seedlings planting, with soil lump transplant is also prone to disease.
(4) prevention and control
1 to strengthen the control of GRUBS, Furadan or methyl-isulphos 3ー5 kg per mu were applied before the soil was turned over in autumn, when the GRUBS were turned over into the soil, the same medicament 3ー5 G was applied in the planting holes, the emergence of adult insects and the emergence of adult insects should be paid attention to the control of adult insects.
2 Peony seedlings were planted in the sun, then the bare roots were soaked in 600 ~ 800 times of wettable thiophanate-methyl and 1000 times of the mixture of isosalifon-methyl for 2 ~ 3 minutes before planting.
Downy leaf blight of tree peony
Commonly known as "Black Knot head disease" , is one of the more serious peony diseases, is a root disease.
(1) Pathogenic Basidiomycete Mulberry
(2) symptoms
When the onset, near the ground roots and roots covered with cotton-like purple or White Mycelium, the initial site of the victim was yellow-brown, later turned black. Old Roots Rot, no new roots, the above-ground branches thin, late germination, leaves become small, and finally from the top down dry and die.
(3) conditions of onset
It happens all the time, all the time. The rainy season in early summer is the peak period of the disease. The disease can also be caused by newly reclaimed land and low-lying wet land, or by improper application of raw and heavy fertilizers.
(4) prevention and control
13 ~ 4 years rotation, pay attention to choose loose soil, good drainage of dry terrain, apply fully decomposed farm manure, avoid direct foundation root fertilizer.
2 pull out the infected plant in time, also can scrape the rotten part with a knife and then use 4 ~ 5 Be mixture of stone sulfur or 1% copper sulfate to disinfect and plant, and disinfect the soil around the infected plant with lime or sulphur.
3 when peony seedlings were propagated by dividing plant in autumn, the roots were soaked in 1% copper sulfate for 3 H or 0.5 H in lime water. Rinse with water and plant.
4 at the beginning of the disease, the roots were watered with 5% ZINCON 1000 times liquid, 500ー1000 ml per plant, and then covered with soil