Peony Care Newsletter July 2016

Peony growth not done after harvest of flowers!

Herewith we send you our Peony Newsletter for July. With special attention to: Phytophthora, organic fertilizers after flowering, botrytis, nematodes and weed control, new planting of peonies and Green Works Care.  We trust that this information will be helpful in achieving a successful crop. For questions or remarks please feel free to contact us.


After flowering fertilization needs to be aimed on the vegetative growth of the plant, the leaves need to grow and fully mature. The leaves that aredeveloping now will form the plants and will be the basis of the flower production the following year. The initiation of the flowers will be in August and September. Take soil / leave samples regularly and in fixed time periods, so that you will get a better view of the needs of the Peony plant.

Normal applications of fertilization kg/ha for peonies on a yearly basis:
(at normal soil values)N-needs, 150 kg/ha
Phosphate, kg P2O5, 100 kg/ha
Potassium, kg K2O, 225 kg/ha
Magnesium, kg MgO, 100 kg/ha

After flowering, fertilize for flower bud initiation next season:

  • Calcium apply halve (for example Calcium)

  • Nitrogen minimal 50 kg

  • Magnesium (Epsom salt)

Be alert that enough water will be available for the plant to take up the fertilizers. Drought in this period will damage the flower harvest for the next year.

An active soil life is very important; moist soil and a correct organic matter level are very important to improve the uptaking of the above mentioned fertilizers.


A fairly new disease in Peonies is Phytophthora. Little damage to the plants will be infected during humid weather conditions and the fungus can survive in the plant or in the soil for years. If the plant is infected by Phytophthora it will show brown to greyish black spots on the stems in the spring. These stems will develop like little black spots and will not grow further than 10cm. Once the plant is infected, it is almost impossible to get rid of it. The spots feel soft and weak and the inside is dark brown. Among others Kansas and Duchesse de Nemours are susceptible. Preventive spraying can be done with for example Mancozeb, Ridomil Gold or the new Signum.

Organic fertilizers after flowering!

After flowering you can apply fertilizers in different ways. DCM offers slow releasing organic fertilizers that fit in perfectly in the Peony growth. Especially after flowering there is a strong need for Nitrogen and Potassium (K) for the production and formation of the plant for next growing season! This way the Peonies will produce maximal stems every year. You can achieve this in different ways. You can choose for a combined organic fertilizer like DCM Mix 6 (6-3-18+3MgO) or apply the elements separate from each other.

When applying separately the combination of Vivikali with a regular Nitrogen fertilizer is well known. The advantage of Vivikali with regard to for instance patent Potassium is the much lower level of salt in this fertilizer. This means that this fertilizer is much milder for the roots. Especially in periods of extreme drought this is very important. Moreover Vivikali contains trace elements, hormones and improves the soil life. Dosage of Vivikali is normally between 400 and 600 kg per ha. When your soil contains more magnesium than Potassium it is at all times a better option to choose for Vivikali.

Because of the drought the taking of elements is not always optimal. A leaf fertilizer is a good option to keep the plant in a healthy condition. DCM has 2 leaf fertilizers which are fast releasers. You can also combine these leaf fertilizers.

  1. Olega complex broad working leaf nutrient (contains all main- and trace elements, sea weed extract and ureum)

  2. Olega fer fast releasing iron leaf nutrient which is very mild for the plant (contains sea weed extract and ureum)

For dosage and application information in combination with plant protection products you can contact DCM, more information:

Andre de Ridder:

  1. Fytaforce Soil for directly increasing soil life by spraying a liquid mixture of fungi, bacteria, yeasts and protozoa
    Fytaforce Soil is a unique, high performance organic fertilizer with a concentrated mixture of beneficial micro-organisms that occur in the soil under natural conditions. It is specifically designed for application at outdoor cultivation and ensures that the natural balance of micro-organisms is restored on and around the plant. In a natural balance, the plant is more resilient and vigorous. In addition, it stimulates the formation of humus and the mineralization in soil.

  2. Photo-Finish for the empowerment of the crop
    Photo-Finish is a multifunctional leaf fertilizer which contains a lot of silicium and potassium which reinforces the cells and increases the sugar level. It also contains kelp (seaweed), humic acid, fulvic acid, selected trace elements and various growth-stimulating plant extracts. Photo-Finish produces a protective layer on the cell walls which makes it an unattractive leaf surface for insects and resistant to fungi.

  3. Root & Shoot for the recovery of the crop and the development of new eyes
    Root & Shoot is an effective product to promote the development of crops, both above the ground and below ground. It is a special combination of fertilizers, growth promoters and vitamins which stimulates root growth and shoot development. Root & Shoot can be used as an aid in times of stress (frost, hail, heat, wind, transplanting etc.), so also after cutting the Peonies. 

For more information contact:

Marco Culurgioni

Danny Rood

Botrytis control

Control of botrytis in peonies is a long term battle. Especially not taking care of botrytis damage after the flowers have been cut is an important measure to prevent many problems. Make sure to spray against Botrytis after the flowers have been cut to prevent further infection. Add Magnesium (Epsom salt) to the Botrytis spray to harden off the plants.

In the fall the fungus will form winter spores which will winter over in between the soil and air. This is also the spot where the infestation starts. Thus control is needed in the spring, but the basis lies in the late-summer. The now much used Collis in the spring is absolutely not a total solution but a part of the solution.

Research has shown that cutting the plants not too short (+/- 10 cm above the soil) in the fall, has a Botrytis preventive effect and thus will decrease the chance of falling over(Botrytis damage) of the stems the following spring.

Leaf nematodes

Deterioration of the leaf nematodes can easily be seen by the deformation of the leaves. The leaves are semi-circular and the tissue is looks deformed. Sometimes it can also dry out the grow point of a young shoot.

Additionally flower bud dehydration can occur. This is clearly indicated by black rotten flower parts surrounded by healthy petals. The exit of the leaf nematodes from the dried buds is beginning to get underway.

For spreading in the plants the nematodes need water. The nematodes move to other parts of the plant by means of water left on the leaves after watering the plants or during high humidity. Spreading also occurs during working with and maintenance of the plants. Because spreading takes place when the leaves are wet, do not walk or spray between the plants but from the paths between the rows of plants.

The nematode will actually only do damage in the season after the infection. Nevertheless the infection can be detected in the first year. The leaves will show blue spots, fixed between the veins. After a rain shower this will spread to the next spot in between the veins.


  • Keep parcel free of weeds.

  • Remove the dried out flower buds.

  • Spray with Vertimec Gold 3 times at night when the leaves are wet with dew, at this time the nematodes will be at the side of the leaves.

  • Cut back the plants around the middle of August and discard the plant rests. Only do this during dry weather.

Weed control

Leaf nematodes travel with weeds (seeds) and infect the parcel
That's why it's important to get rid of all weeds before the winter. Peonies are extremely sensitive for Roundup. Roundup can never be used in peonies, especially with bluegrass. The roots will absorb Roundup in the plant. That means that only Basta remains for an unclean parcel. Possibly add some urea. When there is a lot of bluegrass it is useful to add a small amount of Chlorpropham to Basta.

Leaf spot diseases

Leaf spot diseases are causing more and more problems in the growth of peonies. Leaf spots fungus and Botrytis cause different kinds of leaf spots in the peony, see pictures below. Both fungus spread well during warm and humid conditions. Both fungi survive on crop residues.

Left: leaf spot damage | Right: Brown leaf is Botrytis and the black spot is leaf spot damage (Picture PPO)

Leaf spots are distinguished from botrytis very well, here the symptoms:


  • Botrytis causes a light brown spots whereby the whole or halve leaf is affected quickly

  • The affection is often at the ends of the leaves

  • Develops from above

  • During humid circumstances you will find a gray mould on the affected leaf

Leaf spots:

  • Spots spread over the whole leaf

  • The spots start as light red/purple red specks

  • Later these specks will develop into purple brown patches  


  • Use healthy starting material

  • After mowing in the fall discard the foliage from the field

  • Irrigate in the morning so that the plants will not be moist during the night

  • Spray preventively with Daconil, Flint, Ortiva or Switch. Change regularly between these type of sprays to prevent resistance


Grown crane flies suck just a little bit of nectar. However, the larvae of the crane fly, called leatherjackets, are much more voracious. They are relatively large, soft, fat and eat various plants including peony stems just under the soil.

The crane fly's life can be distinguished in six stages: an egg stage, four larval stages and an adult stage. Adult crane flies only live for a few days. There are species that have one generation per year but there are other species which have several generations per year. This means that throughout the year larvae can cause damage to the plants.

During the day the leatherjacks stay in the soil. At night they come up and eat the base of the stems and the other green parts at the bottom of the plants. They also pull the crop a bit in the ground. Stems with a gnawed stem base will wither.

New planting of peonies


  • Take a soil sample and nematodes sample

  • Very good drainage system

  • Free of perennial weeds

  • Good soil structure

  • Check the crop before planting Peonies with reference to nematodes infection of previous crop

  • Spray on time on the field to make free of weeds

  • For orientation visit the auction and our fields where peonies are grown for resale (long term purchase)

 Planting time:

  • Set up a planting scheme

  • Outside: September March (fall is best time period)

  • Put eyes of Peonies root straight up

  • Preparation of the soil is very important with regard to structure/water drainage

  • Drainage of the parcel

  • Plant in moist soil

  • Take the spraying and harvest of the flowers into account with layout of field

  • Keep into account the possibility of using plastic tunnels in the future (spreading of crop/more yield).

Planting depth:

  • Planting depth +/- 5 cm soil on top of the roots (Will give less flowers when planted too deep. All parts or roots need to be covered.)

Green Works Care™

After extensive testing and research together with various institutions in The Netherlands and abroad we introduce Green Works™ Care for peonies.
The difference between a warm water treatments and Green Works Care™ became very clear after our tests, read the benefits of Green Works Care™ below.


  • No damage caused as by warm water treatments

  • Because the treatment is carried out in-house the plants are less dehydrated

  • Special preventive treatment against root knot nematodes and leaf nematodes

  • Plants retain more growing power and vigor

  • Plant grows better in the first year

  • Producing more flowers in the second and third year


When interested or if you have any questions please contact: 

Check out the Peony assortment per variety: