Peony Care Newsletter April 2016
Herewith we send you our Peony Newsletter of April 2016. 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 moment of choice 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.
Because of its fast growth the peony is not very resistant to changes in climate. From the damage due to fast climate changes, 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 which are mostly used are: Teldor, Kenbyo and Switch.
There are now 3 varieties of Luna. Luna PRIVELEGE can be used for ground application. Luna SENSATION and Luna EXPERIENCE can be used for foliar sprays. Luna SENSATION is also effective in cold circumstances.
When Luna SENSATION is used just before Peonies start to bloom the effects are a lower percentage of botrytis in the bud and a low amount of losses during storage time.
PS After night frost do not spray for 2 days
Flower-bud botrytis is the same botrytis that causes plants to fall over. Thus it goes without saying that parcels which had plants that fell over, are likely to have problems with the flower-bud botrytis.
Falling over of the flower-buds in peonies is an important disease. Even though botrytis spreads fast during wet and warm weather, the largest problems will develop during cold and wet weather, just before the blooming time. The flowers will not ripe and will stay in a vulnerable stadium too long. The fungus will grow from the small leave under the flower into the flower-bud. When it becomes warm and humid, the flower-buds will fall over right before blooming.
A few extra sprayings right before blooming can be necessary, especially Teldor and Kenbyo are mentioned as good and effective pest controls. The best result will be obtained when the flower-buds are wet with dew. The pest control will be easier to apply.
A fairly new disease in peonies is Phytophthora. Little wounds in 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 hawks 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 are susceptible.
Phytophthora is easily confused with night frost damage. In both cases the flower-bud will dry out and will colour black brownish and will turn downwards. The difference can be assessed quickly because with night frost damage a cavity will appear in the stem at the border of affected and healthy plant tissue.
Leaf nematoides can cause the flower-bud to die if the infection is serious enough, but the flower-bud will not bend down. Often little, partly formed leaves can be seen. Therefore it is advised to have these plants tested for Phytophthora to prevent unnecessary use of expensive disease control.
- Use healthy starting material
- Provide a good soil structure.
- Avoid soil that is too moist and provide sufficient water drainage.
- Avoid a soil that has a high contents of salt.
Leaf spot diseases are causing more and more problems in the growth of peonies. Leaf spots fungus and botrytis cause a variety of leaf spots in peonies, see pictures below. Both fungi spread well in a warm and moist environment. Both fungi survive on plants rests.
Patassium is an important fertilizer that makes the plant stronger. Phosphite also strengthens the plant. This results in a defence reaction by the plant. It causes an increase in the salicylic acid route and it slows down the growth and formation of pathogens. Potassium Phosphite pushes the plant to formate more roots. The roots also create a thicker cell wall, making less susceptible to damage from fungi such as mildew, Phytophthora and Pythium.
Leaf spots are can be distinguished from botrytis relatively easy, here are the symptoms:
- Botrytis causes a light brown spots whereby the whole or halve leaf is affected quickly
- The infection is often at the ends of the leaves
- Develops from the top
- During humid circumstances you will find a gray mould on the affected leaf
- 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 discard the plants rests
- Water 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 means to prevent resistance
Color of the crop
The organic fertilizer that is used mostly for outside growth is DCM Mix 5. This fertilizer has a NPK analyses of 10-4-8+3MgO. Besides the fast starting effects of nitrogen, it also has long working effects. The potassium is slow working and this way enough is available to give the plant support at time of harvest. The phosphate is also slow working (released by organic soil material) and has an advantage that the plants can take it well even at higher pH levels (>6). This is important for the rooting of the plant and the forming of the flower-bud. Organic fertilizers are not only longer effective, they are also environment friendly and safe for the plant (contain very little surplus salts). Besides this organic fertilizers will improve the organic material in the soil which is good for soil live.
Micro elements sprinkled
Lately there is a slow releasing micro element mix available that can be sprinkled, called DCM Micro-mix. The micro elements are contained in organic matter so that they are released slowly for the plant. This mix contains iron, mangane, borium, zinc, copper and molybdene. If sprinkled on time the soil supply will stay at a higher level which can prevent a shortage. The micro elements are composed in such a way that they can be taken up easily also at higher pH levels.
Besides sprinkling the micro elements it is also possible to apply iron by means of the leaves. DCM Olega fer is a leaf fertilizer which contains iron, ureum and seaweed extract. The iron in Olega fer is tied to a plant property complex (citrate).This in contrary to most other iron leaf fertilizers which are tied to chelates. The plant property iron has the advantage that the iron will be ‘’recognized’’ by the plant and will be build in at once. Olega fer is fast working, safe to use (smaller molecule than a chelate) and its effectiveness will be stronger in combination with seaweed extract. If leaf fertilizers are used it is important to apply this several times (3-4 times).
Besides Olega fer one can also use Olega complex. This leaf fertilizer contains also all micro elements next to nitrogen, phosphate and potassium. The micro elements are chelatated and in combination with seaweed extract this will provide an extra stimulant.
Olega fer and Olega complex can be used together very well in a ratio of 1:1. It might be possible to add to preventive spray control, but the mixing schedule has to be consulted first.
This can be obtained from one of our advisors via: www.dcm-info.nl/pro/adviseurs/
Silica is important for the strength of the cell walls of the plant. A strong cell wall decreases the chance of diseases and insects to harm the plants. Silica also works for fructification. Dia-Life contains a high concentration of fulvic acid. Diatomaceous earth contains fine relics of seaweeds and consists largely of Silica but also exists of a large variety of micronutrients.
Products from the Life Range, including Dia-Life, contain fulvic acid among other things. This way the plant completely takes in the served minerals within 6 days. Plus the soil life gets stimulated which causes other minerals to be made available for the plant which increases the effect even further.
Flytaforce Soil is a quility biofertilizer with a concentraded mix of positive micro organisms which also occur in the soil under natural conditions. Fytaforce delivers a large amount of positive micro organisms like Trichoderma, Bacillus, Pseudomonas and lots of other positive fungi, bacteria and protozoa. Flytaforce is specially developed for use in the container and full ground outside 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.
For more information about Dia-Life on: www.soiltech.nl
Dia-Life and Flytaforce are available at:
Phone: +31228563135 or contact
Picture bank expanded with shortage diseases
The data bank diseases, pests and weeds has been expanded with a new category. Shortage diseases in nursery stock:
(Web page can be translated on the top right)
Both adult beetles and larvae can cause damage. Adult beetles eat round holes in the leaves, starting at the edge. The Taxus beetle is a pest in many ornamental plants. The Taxus beetle is also known as a grooved vine weevil.
Roots, tubers and rhizomes can be seriously affected by the larvae, but also because at the stem base the bark of the plant is being gnawed on. Because of this there is no sap available so the plants will wither and die. One larva can be enough to allow a plant to die.
Harmful organisms such as fungi and bacteria can enter the plant at the wounds that arise at the root.
An adult Taxus beetle is 8-12 mm long, has a brown/black color and has pale yellow spots. The elytra are grooved and fused with the body so they are not able to fly. They are forced to walk.
From May to October the females lay eggs. The eggs are round and white in color first, but they are turning brown quickly. The larvae live in the soil, are initially 1 mm in length and finally become 12 mm long. The head is brown, the body translucent white to pinkish. Taxus beetle winters as larvae in the soil. The mature larvae pupates in spring in the ground. Outdoors there is one generation Taxus beetle per year. In the greenhouse they develop much faster and several generations can occur every year.
- Taxus beetles can be controlled both chemical and biological
- Chemical control is possible using Calypso
- Biological control is possible by using parasitic nematodes insects
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 Greenworks Care™ became very clear after our tests, read the benefits of Greenworks Care™ below.
- No damage caused 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 content and vigor
- Plant grows better in the first year
- Blooming more in the second and third year
When interested or if you have any questions please contact:
Tel.: +31 (0)6 24 94 64 05
Tel.: +31 (0)6 51 82 47 12
Check out the Peony assortment per variety: