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Rock's Peony, Tree Peony
Paeonia rockii 'Zi Ban Bai'

Family: Paeoniaceae
Genus: Paeonia (pay-OHN-ee-uh) (Info)
Species: rockii (ROK-ee-eye) (Info)
Cultivar: Zi Ban Bai
Additional cultivar information:(aka Purple-white Speckle)
» View all varieties of Peonies




6-8 ft. (1.8-2.4 m)


4-6 ft. (1.2-1.8 m)


USDA Zone 5a: to -28.8 C (-20 F)

USDA Zone 5b: to -26.1 C (-15 F)

USDA Zone 6a: to -23.3 C (-10 F)

USDA Zone 6b: to -20.5 C (-5 F)

USDA Zone 7a: to -17.7 C (0 F)

USDA Zone 7b: to -14.9 C (5 F)

USDA Zone 8a: to -12.2 C (10 F)

USDA Zone 8b: to -9.4 C (15 F)

Sun Exposure:

Full Sun

Sun to Partial Shade



Bloom Color:


White/Near White

Bloom Time:

Late Spring/Early Summer



Other details:

Average Water Needs; Water regularly; do not overwater

Soil pH requirements:

6.6 to 7.5 (neutral)

7.6 to 7.8 (mildly alkaline)

7.9 to 8.5 (alkaline)

Patent Information:

Unknown - Tell us

Propagation Methods:

By grafting

Seed Collecting:

Unknown - Tell us


This plant has been said to grow in the following regions:

Jamestown, Ohio

Gardeners' Notes:


On Sep 7, 2012, midwestfarmwife from Jamestown, OH wrote:

One of the more popular Rockii peony varieties which deserves a place in all flower gardens! Its exquisite white blooms with purple black base petals appear well before our herbaceous peonies. At maturity, Rockii peonies may reach a height of 5' with 100 or more huge, fragrant blooms! They are drought resistant and cold hardy, lasting for decades.


On Jun 13, 2011, cafuller from Edmonton, AB (Zone 3b) wrote:

Planted a 3 year root in 2008 together with 2 other Rockiis, 2 yellow tree peonies and 2 yellow Itoh peonies. The Rockiis grew better than the other peonies and this is the first of the peonies to bloom. These are planted on the East side of my home by the street and get full sun until about 3 PM. I have not provided any winter protection. A -40* C winter killed quite a few of my unusual plants,Yuccas, Agaves, cacti and 1 of the Itoh peonies. The Rockii peonies were not affected.
The blooms stand out and are about 6" across. This is the nicest of the peonies that I grow.