September is the month to divide and transplant garden peonies. Most of us recognize this peony (Paeonia lactiflora) and know it is the State Flower of Indiana.
There was a time when these peonies were called lawn plants because they were plopped as a single plant in the middle of a lawn. The garden peony survives for decades with little to no care. Just drive rural roads on a lovely day in May and see how many are blooming near old, vacant farmhouses or even in what used to be grassy areas.
Now is the time to cut back peonies. Remove any diseased or spotted leaves and stems, but don’t compost them. Rather, dispose of them in the trash.
You can also divide peonies and transplant them this time of year, if desired. Remember not to plant the tubers deeper than about 2 inches from the soil surface, including mulch. Fertilize in spring. Peonies takes a year or two to recover from transplanting before they will bloom again,
The garden peony is one of four Paeonia species to be found in Indianapolis landscapes. Here’s the rundown.
All That Jazz Itoh peony from Plants Nouveau.
Itoh peony
The Itoh peony (Paeonia x intersectional) is a cross between the herbaceous or garden peony and a tree peony. It’s named for a Japanese peony breeder.
“In 1948 Toichi Itoh, a Japanese peony grower and breeder, successfully made an impossible peony cross. Toichi had been trying for years to make the cross between an herbaceous peony (Paeonia lactifolia ‘Kakaden’) and woody tree peonies (Paeonia x lemoinei)with no success,” according to Ohio State University’s Back Yard Garden Linenewsletter.
“It is reported that this was just one of 20,000 crosses he made during his life. It only took one out of 20,000 to change the peony world forever. Sadly, Itoh passed away in 1956 before his plant flowered,” the newsletter said.
Itohs can be pricey. Grow Itohs in full sun to light shade. The flowers usually are larger than garden peonies and there are more of them. They bloom a tad later, too. Maintenance is about the same as with garden peonies. Cut back the stems in fall. Give the plant good air circulation.
I have ‘Cora Louise’ Itoh, which is pink and a reliable bloomer in filtered eastern and southern sun. Just the other day I bought ‘Bartzella’, another Itoh that some how went missing in my garden. This one has yellow flowers, considered a breeding breakthrough. Each of these was introduced in 1986 by a Wisconsin breeder.
New on the market are Garden Candy Itoh peonies. They were developed by Donald Smith of Massachusetts, who has been breeding Itoh peonies since the 1990s. New ones were introduced recently by Plants Nouveau and are available through Monrovia at your garden center and White Flower Farm.
Tree peony
This species (P. suffruiticosa) is a deciduous woody shrub that can reach 3 to 5 feet tall and wide, depending on the cultivar. The stems are woody and unlike the garden peony, are not cut back in fall. No pruning is needed for a tree peony except to remove a dead branch, or in fall to lightly shape it up.
Grow this pricey peony in full sun to part shade in well drained, organically rich soil. Remove spent flowers. Tree peonies may take a few years to establish. Once established, they are difficult to move because of their deep root structure.
Fernleaf peony
A long time ago, someone gave me a red-blooming fernleaf peony (P. ternuifolia) that I promptly planted, and it promptly died. If you read descriptions of this peony, you’ll frequently see things like “for experienced gardeners.” I’ll accept the challenge again.
Another pricey peony, I recently found an affordable one at Old House Gardens, the heirloom ‘Rubra Plena’, which has been around since 1765. It’s about 2 feet tall and usually blooms before other peonies. “It was listed by Philadelphia nurseryman Bernard McMahon in 1806, carried west by the pioneers, and blooms today in abandoned cemeteries throughout the Great Plains,” according to the OHG webside.
Grow in a sunny to partly sunny spot. Rated hardy to USDA Zone 6, OHG recommends applying a non-matting mulch like evergreen boughs over the plant the first winter. Cut back in fall. Fertilize new growth in spring.
Native peonies
California has two native peonies, Brown’s peony (P. brownii) and California peony (P. californica). Brown’s peony, also called western peony, is hardy to USDA Zone 5, but that may be completely different than the Midwest’s Zone 5. California peony is endemic in southwest California and is hardy in USDA Zones 8 and 9.