Tree Peonies

by Julie Pramuk

When we moved into our new home last December, there were two bare trees flanking a camellia tree. I had no idea what they were, but I pruned off the dead branches until I thought I'd left a healthy looking structure. Then, I waited.

About two months later, I saw small distinct leaves appear. Finally, one day I noticed a large bud. I was excited thinking it would be something special, but I still had no idea what it was. Several weeks later we made a trip to Filoli Gardens in Woodside, and there, I spotted a small bush- like plant with the same kind of leaves emerging. The plant tag said, “Peonia.” Then I knew what my two treasures were!

Tree peonies are deciduous. They lose their foliage in the fall, but their woody stems do not die back to the ground like herbaceous peonies. They do best when they have a cold winter for dormancy and hot summers. Usually labeled as a sun plant, tree peonies prefer some dappled to light shade in the afternoon in Napa County with our hot summer afternoons. Their woody structure supports gigantic saucer plate sized flowers on a plant that can grow up to 7 feet high. One of my trees has finished blooming and is full of beautiful shapely leaves. The deep green foliage turns bronze and purple in the fall. So, these trees keep “giving” from early spring on into fall.

Peonies are native to China. They grow slowly and require well drained soil and make excellent cut flowers. If you decide to try growing a peony, they should be planted in spring or fall. They have a high iron and phosphate need and may benefit from an annual feeding of iron sulfate and bone meal in the spring. It's best to water them at the root zone because these plants are susceptible to fungal diseases. Good sanitation around the trees is important. Cleaning up old leaves, twigs, or flowers and pruning off any infected looking part is important. Put all of this waste into your city yard waste container and disinfect pruners with a 10% solution of household bleach between cuts to prevent spreading any disease.

Napa Master Gardeners are available to answer garden questions by email: mastergardeners@countyofnapa.org. or phone at 707-253-4143.  Volunteers will get back to you after they research answers to your questions.

Visit our website: napamg.ucanr.edu to find answers to all of your horticultural questions.

Photo credits: Julie Pramuk

Information links:

UC IPM 

https://www2.ipm.ucanr.edu/agriculture/floriculture-and-ornamental-nurseries/Peony/

http://ipm.ucanr.edu/PMG/GARDEN/FLOWERS/peony.html

http://ipm.ucanr.edu/PMG/GARDEN/culturalmenu.html

UC ANR https://ucanr.edu/sites/uc_master_gardeners/files/139291.pdf