Peony Care August 2014

Dear Peony grower / breeder,

Herewith we send you our Peony Newsletter 2014. 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.

Removing foliage

Peony foliage is usually saved until at least mid September. Saving the green part = saving the growth. Even the dying foliage takes care of the growth of the roots. It is even so that the strongest growth of the roots of the peony happens during dying of the foliage.

Leaf nematodes & flat flower buds

To minimize nematodes and flat flower buds in peonies for the coming growing season you could consider to cut the foliage in the beginning of September.During the winter nematodes survive in leaf rests on the soil and in the young growth points of the peony. In the fall cut back the plants relatively early and discard the leaf rests. Only do this during dry weather.  


If it is not possible to keep the field free of weeds it is advisable to cut back the plants, certainly if the leaves have mostly died. There is no reason to let the plants be if they are being overgrown with weeds.

Leaf nematodes can infect the parcel by lifting on the weeds (seeds).

It is best to control weeds totally before winter. Peonies are extremely sensitive to Roundup. Especially with street grass this product may never be used in peonies. The product is taken up by the plant through the roots. For a weed infected parcel only the product Basta remains. A little ureum can be added. If there is a lot of street grass it is advisable to add a small amount of Chloorprofam to the Basta.

Controlling Botrytis

Although the growing season has just come to an end, preparations are needed to grow healthy plants in the following spring. An important part is the control of Botrytis which starts at the end of the summer. It is important to control Botrytis with among other things Collis after mowing/cutting back.  This is to eliminate any spores that reside on the soil. These spores develop into winter spores which cause falling over of plants in the spring. This spraying in the fall is as important as the spraying in the spring. Discard also the plant rests to prevent Botrytis and nematodes infections!

Mowing height: research showed that if the plants are cut not too short in the fall is a restraining factor for Botrytis. The chance for falling over of plants in the following spring decreases. A mowing height of 10 cm above the soil is better for the plants than directly above the soil.


It is best to plant peonies in the fall. Plants will develop roots better in cool weather and will produce more leaves and flowers the following spring. Try to plant the peonies before half November. Peonies planted in the fall, cannot be cooled during storage. When the cooling period has been too long the plant will start growing before the winter and has a change to be damaged in the winter or early spring.


September/October/November peonies will be harvested and stored until planting time.

Cooling temperature / Outside temperature.

  • If it is not sure that the peonies will be planted before winter, they have to be stored above 5C to prevent premature development of the  sprouts.
  • Until November no cooling, outside temperature.
  • November/December store at 2 C degrees.
  • January store well packed at 0 to -2 C degrees

Do not place plants in air stream of a ventilator to prevent the roots from drying out.

Warm water treatment

Many peonies are given a warm water treatment before being planted again. The advantage of this treatment is that the plants are free of nematodes. Without this treatment this is not possible. Only the root knot nematodes are visible.

The root lesion nematodes are only visible if the plant is severely affected. However the leaf nematode is never visible. The warm water treatment is safest when used when plants are domant. Best time is in the fall; right before planting, preventing drying out of the plants.
The warm water treatment is not without danger. Besides the right temperature (not too high!) and the right time (not too long!) is the cooling down of the plants very important. Lots of damage is caused because plants have not been cooled properly after the treatment.

Yellow fruit tree Cicade

The yellow fruit tree Cicade appears in peonies grown in the greenhouses more often. Because the Cicades only appear after flowering, they are not harmful in small quantities. Most Cicades are seen in August. In September Cicades lay their eggs. Spray with Admire in August, but note that most likely you will never rid of these insects in one time.

Preparing the new growing season

  • Taking a soil sample
  • Taking a nematodes sample
  • Very good drainage
  • Free of root weeds
  • Good soil structure
  • Watch the crop prior to planting peonies in case of nematodes
  • Spray on time
  • Visit the flower auction and parcels where peony roots are grown (purchase for longer period).

Type of soil; sand/clay

  • On sandy soil bed 1.50 m wide 2 rows/minimal space 35 cm.
  • With 3 rows space roots off center.  Minimal space 40/45 cm
  • Sandy soil will produce larger roots
  • On clay soil bed 1.50 m wide 2 rows planting on potato ridges with minimal space of 40/45 cm. Clay soil produces shorter but stronger roots.

Planting time

  • Make a planting schedule
  • Outside: September – March (fall is the best planting time)
  • Plant head/eyes straight up
  • Working of the soil is very important; structure/water drainage
  • Drainage of the parcel
  • Plant in moist soil
  • Pay attention to spray beds/carrying flowers out of the field
  • Keep in mind the placing of tunnels in the future (spreading of harvest/larger yield)

Planting depth

  • Planting depth +/- 5 cm soil on the roots (if planted too deep plant produces less flowers).

More information

Check out our current assortment of Peonies here: Peonies Assortment

For more information contact directly:

Green Works International is a supplier of young planting material for the professional cultivation of pot plants and summer cut flowers. Green Works provides additional support with the growth, promotion, marketing and sales, offering a total package to bring into the market an unique and healthy product.