Peony bush not blooming

(Question)

I have an early variety deep red double peony bus. In the past it would be loaded with buds. However the last few yrs it is producing fewer blossoms. This season I only had two and the bush itself is not as full and leafy. This bush would be approx 25 yrs old. Not sure what I can do for it to produce more flowers. I have 3 other peonies in the same area and they are loaded with buds. Regards Brian Birkby

(Answer)

Thank you for contacting the Toronto Master Gardeners. Peonies are such beautiful flowering perennials and a wonderful addition to any garden.

From the description of your non-blooming situation, there can be several issues at play, see below:

  1. Peony bulbs (tuberous) are situated too low below the top soil level.  This can happen over time if soil amendments or mulch is added annually to the flower bed.  In this situation, lifting the bush and replanting it no deeper than 2 inches below the soil surface would be ideal.  This can be done in the autumn when the plant is starting to die back for the winter.
  2. As this is an old peony, when raising it, you should consider making divisions.  Large plants can easily stand to be split and transplanted to another garden location, making sure you have 3-5 eyes in each division.  Again, this procedure is done in the autumn.
  3. Peonies do well in sun to partial shade, but if the light conditions have changed in your garden, creating more dense shade, it may be time to move the plant into a more suitable brighter location.
  4. Soil should be rich and amended with well-rotted manure or compost, as these plants need macro, and micro, nutrients to thrive and flower, so if raising or transplanting, amending the planting area would be worth doing.
  5. Under watering, and over watering, can also cause peonies to fail to bloom so this should be monitored.  If you have a sprinkler system, is it reaching the other plants but not this particular one.
  6. Over fertilizing is another consideration as this will cause too much vegetative growth at the expense of blooming.  Under fertilizing will cause plant stress where it puts its resources into finding water & nutrients at the expense of flowering.
  7. Heat stress can also be an issue if your garden bed has changed, and your bush is more exposed to wind and sunlight, which can cause fairly rapid soil moisture evaporation.
  8. When the foliage dies back in the autumn, clean up all debris and dispose of it with the city garden waste program, do not put it into your own composter, should you have one.  Doing this will prevent the spread of any pests or disease that may be harboring on the leaves.

This is a general guide to good peony growing practices – hope this is helpful.