Peony newsletter, March 2016

Herewith we send you our Peony Care Newsletter for March. Information currently relevant to the crop of peonies will be given special attention. We trust that this information will be helpful in achieving a successful crop. For questions or remarks please feel free to contact us.


The peony is a sensitive plant. After sprouting the plant will grow very fast and thus not very strong. If the growth is fast while the weather is bleak, the plant will abort the weakest flowers. Especially during cold nights the frost will be blamed for this, while lack of water will most likely be the main reason. A sudden spell of warm weather during the stretching will increase the risk. Do not wait with watering until the soil is dry, but make it as pleasant for the plant as possible.
In the greenhouse or in the plastic tunnel watering peonies is very important for the result. Because the plants grow very fast there is a big chance that the plant growth is more important for the plant than the growth of the flower stems. Sufficient watering will delay the so-called choosing moment of the plant. When the flower buds are large enough, the plant will not abort them anymore. Watering demands paying attention to the climate.
Avoid big changes in temperature and humidity, timely air and provide an easy growing period. Only opening the windows when it is warm, can cause Botrytis. Growing too dry in order to prevent Botrytis will cause dried up flower buds. The irrigation should be optimal for a better development of the flower buds. If not, one problem will be solved at the expense of another one.


The first treatment against Botrytis will have to take place when the plants start to emerge. Due to the fact that the fungus  lingers during the winter at the surface of the soil, the new shoots will be infected during emerging from the soil. Drenching the soil with Collis can reduce the number of infected plants, for example with a sensitive variety like Flame, by more than 90%. Peonies damaged by the wind and frost are also more sensitive. Varieties in which Botrytis was more present the previous season after flowering, need extra care. Therefore we would like to emphasise the need to treat plants timely and preventively. There is an advantage in doing so. The dosage is maximal 4 litre per ha and works best when as much as possible is drenched on the plants with lots of water (for sensitive plants 0,20 litre per plant). Using Collis regularly is not an option because of resistance. Loosening the top soil in the poly houses and greenhouses can reduce damage by Botrytis.

Because of its fast growth the peony it not very resistant to changes in climate. Around the damage due to this, Botrytis will most likely appear. Especially when peonies are not protected sufficiently during growth, the fungus will cause large problems. Extra spraying is most definitely needed during this critical period. Good and effective products are Teldor, Kenbyo and Switch which are usually used.

PS: after night frost do not spray for 2 days.

Botrytis in the crop

Shot hole

During the cultivation of the Peony plant there can emerge holes in the leaves. The holes do no only reduce the growth and ornamental value but also are an opening for other diseases like Botrytis. The arise of holes in the leaves is most known from shot hole in prunus. That’s why this disease is called shot hole disease or shot hole.
Over the past 10 years Shot hole has been causing more and more damage to the cultivation of peonies. The cause of shot hole in Peonies is unknown.

The symptoms
Red purple leaves are visible on the leaves. Eventually the spots will dry from the core to the edge. Thereafter holes will arise because the dried tissue will fall from the leaves. A red colored edge will stay visible around the hole. Typical is that the shape of the edge of the hole is inconsistent and that the holes and spots vary in sizes: from less than a centimeter till multiple centimeters.

Sensitivity of the crop & circumstances at infestation
Consult with growers shows that they have observed the symptoms at different points of time. Multiple times it was indicated that the shot hole arose right before the blooming or at the spreading of the leaves. In another case the symptoms were only seen after the harvest. Especially a crop that does not look full grown is sensitive for shot hole. Moist periods appear to stimulate the chance of shot hole in Peonies. It appears that shot hole does not occur at young crops (till several years after planting). Also shot hole does not occur in the Greenhouse.

Hail shot in the leaves

Experiences in controlling shot hole
Various broad spectrum fungicide against Botrytis are being applied to Peonies. A lot of these means are also being adviced to use for the control of a wide variety of leaf spot diseases in various ornamentals. Despite the use of fungicide against Botrytis the problems with shot hole have increased. The experience with shot hole is very limited. After recognizing shot hole some growers have sprayed extra with broad spectrum fungicide like powdered sulfur and TMTD (thiram).

The most important conclusions are:

  • The size of the problems on a national level are increasing but is still limited
  • Several years after planting shot hole causes problems in the outdoor cultivation with peonies
  • The spreading and symptoms from shot hole are pointing to a leaf spot disease which can spread above ground within one growing season
  • There are various indications that a humid environment can increase the chance of shot hole infestation on the crop
  • The disease occurs on various soil types
  • Shot hole can hibernate in a crop (in the crop, crop residues or in the soil) and cause damage in next year’s crop
  • Regular sprays against Botrytis do not prevent shot hole. The experiences with specific spraying against shot hole are too limited to draw conclusions of the effects
  • In shot hole effected leaves there are various fungi and bacteria present from which is known to cause leaf spots in peonies (Botrytis) or other crops
  • The infection test has yet to make clear if the cause of shot hole is present in the found fungi and bacteria
  • To prevent and to control shot hole in peonies it is still wise to follow general advice on how to prevent and control leaf spot diseases in summer flowers and perennials

Who is Soiltech?

The resilience of the soil and the plants that grow in it is created primarily by nature itself. This is the philosophy behind Soiltech’s soil analyses and tailor-made fertilisation advice for tree, ornamental, fruit and vegetables growers and public landscaping projects. Soiltech has a broad range of products in order to achieve sustainable cultivation and drastically reduce the use of chemical products and increase growth of the plant.
Soiltech focuses on increasing soil resilience and optimal nutrition for the crop.

Are you prepared for the coming season? Perform a soil analysis!
It is the beginning of the year and the cultivation is on hold. Time to take stock. Not only of the income and costs but also of the most important part of the cultivation: the soil. Does it still have the right balance? Are you making use of everything it has to offer? A soil analysis answers all those questions.

What is a soil balance analysis(SBA)?
A soil balance analysis (SBA) reveals the ratios of the various minerals and trace elements in your soil. The soil balance is determined on the basis of the TEC (Total Exchange Capacity). This value indicates the soil’s clay-humus complex, and hence its potential for retaining minerals and supplying them to plants. The SBA also determines the concentrations of the various minerals on the clay-humus complex. This reveals the ratios of the various minerals in your soil. It is very important to know what these ratios are, as this tells you which nutrients to apply to your soil to bring it into balance. These nutrients vary per soil and variety. We are glad to help out with a personalized fertilization advice.

Everything depends on a good preperation
This is a perfect month to get an SBA done. There is almost no cultivation done and the soil has come to rest. This is important to get the most reliable information. Because the soil samples are being analyzed early in the year there is still plenty of time to resolve any complications in the soil. This will make sure that the soil is in optimal balance at the start of the new season!

Why do a SBA?
An SBA checks the overall need of the specific soil. In contrast to some other analyzes where they work with a region average for measurements. The SBA gives a specific advice per element of the sampled soil.

Contact your advisor for tailored advice.
Jelle Havermans:
+31(0)6 – 51 13 47 80

Weed control

Weed control in perennials is more a matter of discipline than the choice of means. With weed control the amount of organic content is almost only the most important factor. A heavy clay soil with almost little to no humus is light soil for weed control. The effect of a mean without damage is being determined by a small line between effect and damage. The most means for weed control work best in the first period after application. When there is not being sprayed on the right moment then a higher dosage is needed. However, this also increases the chance of damage to the plants.
When the buds are visible it is time to spray with Goltix and Olie-H. Goltix has the best results on a moist surface. Do not spray at sunny weather, spray late in the afternoon. When night frost is expected Goltix can also not be used because of the rapid degradation of the plant.

PS By lifting on weeds(seeds) leaf nematodes can infect the parcel

It happens under the soil

The silting of the soil is due to not enough bonding between the soil particles. The many periods of rain causes the soil to harden. Especially the lighter clay soil and loss soil are sensitive to silting. The sensitivity to silting is caused by  the organic material and lutum content of the soil. Silting of soil containing more than 20% of lutum will almost not happen. Also soil that contains very little lutum does not silt easily. Problems appear in soil containing between 11 and 20% lutum. If the soil contains sufficient organic material, silting is less likely to occur. Silting of the soil can hinder the rooting because of lack of air. Not all plants are strong enough to break through the hardened top layer of the soil. Also after emerging there can be a lack of air. The soil can stay moist long and can be hard to work with. You can decrease silting by increasing the organic material content of the soil.
Ca levels also need to be looked at. Because Ca is good to improve the structure. It is important to give the right chalk at the right moment. The best solution for when you still need to strew chalk this period is a young chalk like the DCM Fossil Seaweed chalk grain. DCM Fossil Seaweed grain is soft, works quickly and contains 45% calcium and has a neutralizing value of 50.
The best solution for spring application!

Organic matter is very important for the fertility of the soil. It enables it to keep moisture, is important for the tilling the soil and it can bind and release nutrients. The organic matter level decreases among other things because it serves as food for the soil live. The soil live eats the organic matter and during this process nitrogen, sulphur and other nutrients are released which can then be absorbed by the plants. The organic matter level can decrease fast, but cannot increase fast! It is very important that this level stays the same. To keep the organic matter level at the same level you can work with manure and compost. Use grand-pa knowledge for a healthy soil live and organic matter level and the advantages of fertilizer.

Soil live
is of great influence on the growth of the plants. Soil live processes the organic manure so nutrients are released which are indispensable for the plants. Furthermore the soil live has more functions:

  • Breaking down of plant rests, manure and dead soil organism and the releasing of nutrients
  • Build up of organic matter that will be broken down very slowly
  • Build  up of a good soil structure 
  • Limit the breeding of disease organism


Now that the growing season is right around the corner it is also time to fertilize the plants.

You can work from the soil analysis in which the nutritional status is indicated so that possible deficits can be repaired. In the cultivation of peonies several organic fertilizers are being used. Difference is made between inside- and outside growing. Below a list of products being used mostly for this:

Inside growing

  • DCM MIX 2 (7-6-12+4MgO) – granular fertilizer with higher kali for strong leaves
  • DCM MICRO-MIX – granular micro elements mix (encompasses iron, mangane, copper, borium, zinc, molybdene)
  • DCM VIVISOL® – granular, creates a rich and variegated soil
  • DCM OLEGA® FER – quick working iron leave nutrition

Outside growing

  • DCM MIX 5 (10-4-8+3MgO) – granular fertilizer
  • DCM VIVIKALI® – slow release organic kali
  • DCM VIVIFOS® – slow release organic phosphate (also good available with high pH)
  • DCM OLEGA® FER - quick working iron leave nutrition

For custom advise you can contact your advisor or Andre de Ridder of DCM Fertilizers:


When you have questions, want more information or are interested in Peonies please contact:

View the Peony assortment per variety:

Or click on one of the Peonies below for detailed information of this variety: