The rarest color of peony is true blue. It does not exist in nature and no breeder has ever made one. Pure black peonies don't exist either, despite what some online sellers claim. The darkest peonies reach a deep burgundy that looks almost black in dim light. But no peony makes genuine black pigment in its petals.
When I first visited a peony nursery in Oregon, I was hunting for unusual colors. The owner walked me through rows of coral, lavender, and deep plum plants I had never seen at any local garden center. When I first spotted a true lavender peony in person, it stopped me in my tracks. The color was so different from standard pink and white that I bought three plants on the spot. That trip showed me that rare peony colors do exist if you know where to look.
Your peony petal color comes from flavonoid and anthocyanin compounds in the cells. These pathways can make white, pink, red, coral, yellow, and purple shades for you. But they can't produce the delphinidin pigment your flower would need for true blue. No amount of breeding can fix this gap. Peonies lack the enzyme to make that compound. The same limit is why true blue roses don't exist either.
The rare peony colors that collectors chase fall into a few groups. Deep purple tree peonies from Japanese breeding programs reach the darkest natural shades. Coral peonies like Coral Charm shift color as they open. They start salmon and fade to soft peach over several days. Yellow peonies were hard to find until Itoh hybrids like Bartzella came to market in the 1990s. Lavender shows up in types like Do Tell and Cora Louise, though they lean more toward mauve.
The full natural color range runs from white through deep purple based on NC State Extension data. Unusual peony varieties that push the edges of this range cost more. A standard pink root runs $15 to $25. A rare Itoh hybrid in coral or yellow costs $40 to $80. Named Japanese tree peonies in deep purple can reach $100 or more for a grafted plant.
Source your rare peonies from specialty nurseries that grow their own stock or import from known breeders. Skip mass-market sellers who slap fancy color names on standard types to charge you more. A good nursery will list the cultivar name, breeder, and year for every plant they sell. Look up the name on the American Peony Society list before you buy. The effort pays off when your garden blooms in colors your neighbors have never seen.
Read the full article: Peony Flower Guide for Every Garden
