Fully understand the growth habits ofpaeoniarockii in summer

 The growth habits of paeoniarockii in summer are mainly affected by its native environment (arid and cool areas in northwest China), showing the following characteristics:

1. Like coolness, avoid high temperature and humidity:
   This is the core growth habit of paeoniarockii in summer. They are very intolerant to high temperature and humidity.
   When the temperature continues to exceed 30°C, especially when the humidity is high at the same time (such as the plum rain season in the south and the hot weather in North China), the plant will enter a semi-dormant or growth stagnation state.
   High temperature and high humidity are the biggest threats to the poor growth and outbreak of diseases and pests of paeoniarockii.
2. Like sufficient light, but need appropriate shade:
   paeoniarockii is a sun-loving plant, and it needs sufficient light (at least 6 hours a day) during the growth period to ensure strong growth and flower bud differentiation.
   However, in the hot summer (especially at noon and afternoon), strong direct sunlight will burn the leaves and aggravate high temperature stress. Therefore, in high-temperature areas in summer (especially in the south and low-altitude areas), it is necessary to provide about 50%-70% shade (such as shade nets, next to big trees) to avoid leaf burns and reduce the temperature around the plant.
3. Drought resistance and fear of waterlogging:
   The root system of paeoniarockii is well-developed and fleshy, and it is very afraid of waterlogging. Summer is a season of concentrated rainfall and frequent rainstorms. Poor drainage is fatal and can easily lead to root rot.
   Although it is drought-resistant, during the hot and dry summer period, the soil still needs to be kept moderately moist to avoid excessive drought affecting the vitality of the plant and even causing the leaves to burn. Watering should follow the principle of “see dry and wet”, avoid frequent small watering, and the best time to water is in the early morning or evening.
4. Post-flowering growth and new bud differentiation:
   After the spring flowering period ends (usually in late May and early June), the growth focus of paeoniarockii shifts to vegetative growth (branch and leaf growth) and flower bud differentiation (preparing for flowering next year).
   Summer (June-August) is the critical period for flower bud differentiation. At this time, the plant needs to accumulate enough nutrients and complete the morphological differentiation of flower buds at a suitable temperature. High temperature stress will seriously affect the quantity and quality of flower bud differentiation.
5. High incidence of diseases and pests:
   The high temperature and high humidity environment in summer is very likely to induce various diseases and pests, and it is a key period for prevention and control.
   Common diseases: leaf spot (brown spot, anthracnose, etc.), root rot (mainly caused by waterlogging), gray mold (when humid).
   It is necessary to strengthen ventilation, clean up diseased leaves and branches in time, and spray protective fungicides and insecticides regularly for prevention and control.
6. Fertilizer is needed but avoid concentrated fertilizer:
   After flowering (late spring and early summer), compound fertilizer mainly composed of phosphorus and potassium fertilizers can be applied once to supplement flowering consumption and promote flower bud differentiation and root growth.
   Fertilization should be stopped during the high temperature period in midsummer (usually the hottest in July and August), especially nitrogen fertilizer. At this time, the plant grows slowly or even stagnates. Fertilization not only cannot be absorbed, but it is easy to cause fertilizer damage and burn the root system.
7. Proper pruning:
   After flowering, timely cut off the remaining flowers to avoid fruiting and consuming nutrients.
   In summer, you can appropriately thin out the dense, crossed, inward-growing branches, as well as the weak and dead branches, to improve ventilation and light transmission conditions and reduce the occurrence of pests and diseases. Avoid heavy pruning.

Summary of the key points of summer maintenance:

Core contradiction:

Solve the stress caused by high temperature and high humidity.

The first task:
Ensure that drainage is absolutely unobstructed!

It is better to be dry than waterlogged.

Proper shade:Avoid exposure to the sun and reduce local temperature.

Strengthen ventilation:Reduce humidity and reduce pests and diseases.

Water management: “See dry and wet”, avoid water accumulation, and avoid watering during high temperature periods.
Fertilization management: Supplement phosphorus and potassium fertilizers after flowering in early summer, and stop fertilizing during the high temperature period in midsummer.
Pest and disease control:

Regular inspections, timely prevention and treatment.
Pruning:

Cut the remaining flowers after flowering, and lightly thin in summer to improve ventilation.
Understanding and adapting to the core habits of paeoniarockii that they like coolness in summer and are afraid of humidity and heat, and taking the three most critical measures of shading, ventilation, and drainage, are the basis for helping them survive the summer safely and ensuring flowering next year.

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.

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.

Peony Flowers to bloom, spring management is very important, teach you a few management skills

 The temperature gradually rose in spring, peony also began a year of growth recovery, peony spring care is directly related to the growth and flowering of the peony

Flowers, then, how should Paeonia suffruticosa be managed in the spring? Next for everyone to introduce the peony spring maintenance management points.

First, spring peonies need a little pruning

Peony flowers, to the spring, as the weather is warming, its bud has appeared, at first looked small, but can already be recognized, at this time we should pay attention to a little pruning, pruning mainly to complete the following tasks, first, we should trim the dense branches to improve the light, and second, we should cut off the dense flower buds. After all, peony flowers consume too much nutrients, if the flower buds are too much, it will lead to too much nutrient dispersion, peony flowers are relatively small, loss of aesthetic appeal.

In spring, the peony will sprout more soil buds from its roots. Some friends will say, isn’t this a good thing? Don’t you get more young peony plants? In fact, this understanding is wrong. Most peonies are obtained through root grafting of Paeonia lactiflora pall. The soil buds from the root system can not produce dainty peonies, and they compete for nutrients. These are very disadvantageous to peonies, so you have to get rid of it in time.

Second, the peony flowers to the spring should be timely fertilization and watering

The peony flower will bloom in the future, and the consumption of nutrients is relatively large. After a long winter, the peony flower has already consumed more nutrients, so it is very necessary to supplement nutrients in time, in other words, we should fertilize Paeonia suffruticosa in time. We should fertilize peony flowers. We should pay attention to the use of decomposed organic fertilizer, such as decomposed cake fertilizer, decomposed animal waste, etc. . These fertilizers have stable nutrients, can improve soil fertility, more importantly, can improve the quality of peony flowering, bloom in the future, let the flower color more charming.

Use decomposed organic fertilizer at the same time, we can use compound fertilizer, let the inside of the nitrogen element to promote growth, inside of the phosphorus and potassium elements to promote flowers, at this time absolutely can not partial fertilizer nitrogen fertilizer, partial application of nitrogen fertilizer will lead to excessive growth of nutrients in peony flowers, weaken the growth and growth, the flower bud can not get such elements as phosphorus and potassium breeding, will make the flower bud thin and weak, and even will disappear.

If we want to make better use of the fertilizer effect, we should also pay attention to reasonable watering. We should not water too often, otherwise the fleshy roots of peony flowers are easy to be soaked and rot, when watering should wait for the soil to become dry two or three centimeters again water is not late, water must be watered thoroughly.

Third, the peony to see more sunlight, pay attention to ventilation loose soil

If the peony flower wants to blossom in spring, it must pay attention to give it more moderate sunlight. The sunlight in spring is very mild, which is good for the peony flower to carry out photosynthesis, to make more nutrients, and is good for the plumpness and expansion of the bud, if potted peony, it should be placed in a well-lit place, in addition to pay attention to timely ventilation, so that peony growth can be more state.

The root system of peony is fleshy root, not water stain, like to breathe, so you can loosen the soil, loose soil, peony root system will be very good breathing and relaxation, absorb more nutrients, to promote plant growth.

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