June 13, 2015


The intersectional Itoh hybrid peonies are a cross between the traditional herbaceous type, and the tree peony. These sturdy and strong growers die back to the ground like perennial forms, but produce sturdier stems and large flowers, often in colors only found in tree peonies such as Yellow. This variety is 'Bartzella'.

I don't know if you've noticed this or not, but this seems that 2015 is the year of the peony - at least, in our gardens in the Northeast.
The reasons are unknown, but it could have been our awfully cold (or awesome?) winter, or just might be something to do with better varieties coming into the market and thus, into peoples gardens. I have received  so many questions about peonies lately - most seem to be about weak plants, or trying to get their peonies to bloom, and more than a few about when to transplant. I felt that it was worth a quick post (it's a little long, now that I look at it) on how I grow peonies, and some shared thoughts on these lovely yet sometimes difficult plants.

Ask gardeners who have peonies in their garden and they most likely will just exclaim that "they are easy", often adding that they do "little to nothing other than pick them each June", but to those of you who either struggle with peonies, or who are looking to plant some this year, there are a few tricks to know that may help you.

First, a brief primer about peonies -

Most experts divide peonies into about 5 distinct types

1. Herbaceous - these are your classic peonies. You know, Martha Stewart's peony garden, long rows of every shade of magenta, coral, pink, peach, salmon and white. The term herbaceous means that they will die completely to the ground come winter, and reemerge again in the spring.

2. Tree Peonies - These are peonies that form woody stems which do not die to the ground every winter (OK, sometimes they do, but generally speaking, in milder areas, they will form longer and longer woody stems, never as bushy as a shrub, but when they are in full leaf, they will have the stature of a shrub. The large foliage will still drop off in the winter, but with each year, the plants should get larger and more impressive in bloom.

3. Intersectional or Itoh Hybrids - these are the newest peonies on the block, and they are spectacular. A cross essentially between the above two types ( herbaceous and tree), they carry the best characteristics of both types - stronger stems, larger flowers in a broader range of colors, yet they die to the ground every autumn.

4. Rock Garden Peonies - These are generally higher elevation or smaller woodland species, great for rock gardens or alpine gardens, or for special places where their fantastic ferny foliage can be appreciated. I only call these out differently from the below 'species' category, as there are not some named varieties coming into the trade, and most catalogs categorize them separately as 'rock garden' types.

5. Species peonies - There are species, or wild peonies in all of the above categories except Intersectionals. Over the past couple of decades, a better selection of species have been introduced, most make terrific garden specimens given time, as most species take a painfully long time to mature int he garden. These are plants which our parents and grandparents only wished that they could grow, and once you see one full grown, you will want any one of them in your own garden.

Ten year old 'me', already a hopelessly obsessed plant boy.

My personal story with peonies goes way back to my childhood. Living now in the garden where not only I was raised, but my father and his brothers, I am fortunate to have old peonies which my grandmother raised. I never met my grandparents, since they lived here from around 1906 until 1945 or so ( my dad died a year ago last week at 100 - clearly, I was the 'accident'). Peonies played a role in my budding botanical interests as a child. My mother like to tell the story of how she and Elenore (the woman across the street who still lives here at age 90-  Hi Elenore!) dug and transplanted peonies from a neighbors 18th century home (Mrs. Hook), down the road. They planted them near our little concrete goldfish pond in the late 1940's, where roses once grew. These varieties, combined with my grandmothers became the foundation of the peony collection.

Most are lost now, but they were the annual highlight of the garden until I moved back to take over the property in the 1990's. When I decided to build the greenhouse in 2001, the only way to get a tractor into that side of the yard, was directly over the peony garden, which to be honest, by then was failing somewhat due to shade from trees which only have grown taller over the years. I was able to save a few, but most did not recover.

A couple of my mom's original peony varieties still in bloom this week, after a thundershower. They are weaker than most new selections, and fall over from the weight of their blossoms, even when not wet. But come on - they are like an annual visit from my mom, so they are priceless to me.

It may seem sad to lose these old varieties, but I think that I could replace most of them, with a simple visit to a good peony nursery. I am certain of a few of the varieties, which are most iconic such s 'Festiva Maxima' - a classic variety circa 1851, but with a smaller garden, I have to admit that I am enjoying the newer selections as they not only produce a better show when in bloom, they also have foliage which looks terrific for the rest of the summer.

I am smitten by the newer Itoh Hybrids, often yellow or in warmer shades - you may have seen them sold at your local nursery in 5 gallon Monrovia pots for anywhere from $60 to $200. Don't think that these are anything like your old fashioned peonies - they are superior, and although expensive, they are worth the investment, if you think of them as adding a shrub or a hydrangea to your garden.

Itoh Hybrid peonies are far superior to many of the older selections of herbaceous, but there are plenty of good herbaceous ones too.

The term 'new'  however, is a little misleading, as Dr. Itoh himself passed away in 1956, and ironically did most of his plant breeding in the 1930's and 1940's just as my parents were moving around all of those ancient, varieties from the 1800's in my garden.  They would never have known about these new crosses, as it took time to get them ready for market, most didn't appear on the scene until the late 1990's.

My tree peonies this year are loaded with blossoms, most every stem terminated with a large flower - best thing about tree peonies? They blossoms remain upward facing, and don't tip over in heavy rain or dew.

Although old-timer or heirloom havethe charm of antiquity which when it comes to peonies, can be a good  story indeed, as it is one of the auspicious Chinese plants cultivated hundreds of years ago - In Japan, I've visited peony garden planted for Emperors which had plants that we 300 years old - but in our home gardens, a better show can be had with a variety of old and new selections. When it comes to peonies, 'heirloom' doesn't always tranlate into 'better' - there are subjective points, such as fragrance or color, or even vigor, and there are good and bad peonies on both sides of the dateline, but newer breeders do cull out the underperfomers - point is, we demand more for a peony today, so newer peonies tend to be more vigorous and awesome.

Today, the genus offers so much more than just the floppy, weaker growing varieties which don't get me wrong, are still lovely, but pale in comparison to the displays produced by either the Itoh crosses, or many of the species forms. Each, unique and special, and surely once viewed in real life, will be added to your 'must get' list.

Tree peonies can be challenging for some people, but if there is a trick, it lies with providing winter protection in the late autumn - I use Styrofoam rose cones weighted down to minimize wind damage, others use straw or hay, but the best trick of all, may be to simple wait 5 years for your plants to settle in and mature.

As for species forms, briefly, as I doubt many average gardeners will want to either pay the prices or be patient enough to find one of the better species peonies ( 'species', as those peonies which grow in the wild such as Paeonia rockii and many others). Each will take some time to mature ( even more time than the Itoh inter sectionals), but once they do, you will have a true treasure.

When to plant peony plants

If you order via mail, autumn is the best time to plant peonies. It also is the best time to transplant peonies, but be careful here - autumn is recommended because the peony plant, as a whole, has completed it's growing cycle for the year ( it actually completed it by mid summer, but wait until cooler weather to move them).

Understanding how a peony grows, will help you understand why autumn is often suggested as the best, if not only time to move them. Peonies are essentially woodland plants - they form their buds in the previous year, just near the surface of the ground where the large, woody roots are showing.

You will see these buds by late summer, if you peek near the surface of the ground. This early prep is one reason why one is often told to not plant peony roots deeper than how they were planted originally, and why mulches which are heavy such as wood bark must be used carefully, or pulled away front eh crown of the plant. It's this intersection between what is above the ground and below the ground, which is important. One does not want buds forming too low under the ground, nor have their woody roots extending too much above the soil.

A yellow Itoh Hybrid blooming this week - standing proud after a severe thunderstom passes, just as the sun was setting. This one is 'Bartzella', which is available at many good garden centers, but be forewarned, it can be pricey.

In early spring, these buds begin to lengthen, and they are one of the first signs of spring in a perennial border or garden - often reddish in color, due to the cool air of April, these buds quickly lengthen and turn into stems with leaves, and if one is lucky, a marble sized or golfball sized knob of a bud appears at the apex of each stem.

By late May or early June, these flower buds mature, open and then shatter - all within a few days, and the floral display is over for the season. One should cut the seed pods off ( unless it is a species form, as you will want either the impressive seed pods, or the seed to start yourself - but if it's any other type of peony, it's best to cut the seed pods off, so that all of the plants energy can go back into those thick, woody roots, which will only make the plants more impressive next year.

If you see peonies now at the garden center, it's OK to plant them, as they have been raised in a container, and you can carefully slide the rootball into a prepared hole. These expensive Itoh hybrids for example will transplant perfectly fine during this current spring or summer, since they are large clumps in 5 gallon containers. Most of the problems I find come with inferior varieties from questionable sources - dollar stores, hardware stores where they came in a box with a poly bag, or mail order sources that were not of good quality.

Be smart with peonies - as you will get what you pay for. Order from a known peony specialist such as Peonies Envy (I have not tried them, but other people like their selection) and I highly recommend  Song Sparrow Nursery. Better yet-- visit the website of the American Peony Society for sources that they recommend. There are plenty of good sources which also happen to sell other good perennials such as Iris and Daylillies. I would avoid the larger trade nurseries - those color catalogs such as Spring Hill, van Bourgondoin, etc, as they will ship small roots which may even be bare root.

A few weeks ago I posted this tree peony blooming in front of the greenhouse. It stayed in bloom for nearly 3 weeks.

When to divide peony plants

Peonies can be divided - in autumn, if you have a large clump which is more than ten years old, or one which suddenly isn't performing as well as before. Dig the entire clump up with a deep root ball, and carefully wash off as much soil as you can. Be careful, as buds will have formed already near or just below the soil line. The soil may completely fall off the thick roots, as the clump may look more like a clump of brown parsnips than anything else. Try to be generous with your divisions, as smaller portions will take years to recover. Leaving 3 or 4 roots to a trio of bud might be ideal. Carefully set into a prepared hole, no deeper than how they were before, and water well.

As for the term 'prepared hole',  it depends on where you live, but Peonies enjoy a slightly acid soil, which might be one reason why they do so well for us here in New England. A pH of 6.0 -7.0 is ideal. Lime is rarely needed, as is heavy fertilizer. Some older books used to quote that same advice as for asparagus - well-rotted manure, deep hole, etc -- but come on, who has access to well rotted manure these days?

A sensible hole prepared as one could prepare for a shrub is all that is needed. I apply a granular balanced fertilizer once a year (a 10-20-20 is strong, but OK if time released or granular - or look for an analysis where the first number, which is nitrogen, is lower than the second two numbers - one wants strong roots and flower bud formation, more than foliar growth.). granular fertilizer should be scratched in around the crowns, being careful to not allow it to touch any growing parts.  I sometimes apply an annual application early of a granular super phosphate in March as well. More importantly, in fall when plantings, a kickstarter handful of 10-10-10 for each crown is a good baby-food insurance application of food, which can be helpful when first setting out new plants into your garden. It makes more sense to feed early in the plants life, as mature plants with adult roots do find without any additional food.

Aside from an annual clean-up of foliage after hard frost, and the removal of seed pods (dead-heading) peonies are carefree, as the foliage remains until late autumn. If you wait until spring to clean up herbaceous plants, be sure to cut the stems back to an inch or so above the ground. It's best to not leave these to die naturally through the winter, and don't try to pull them off of the plant in the spring, as they are stringy and can pull out or damage the roots or small buds - I learned the hard way.

Overall, Peonies are easy - once you get past the first 3-5 years of them 'settling in'. Remember, there are cemeteries and old gardens where there are peonies growing un-cared for, and they have been blooming for more than 50 years. They are truly long lived, once you get them established.  Just remember, plant then in fall ( not those 4 inch boxes of plants one sees in the spring at Home Depot, Lowes and Tesco - order yours from good retailers in late summer for fall delivery). Beyond that 50 year mark, they can even last a lifetime ( or even 2 or 3 lifetimes, as in my garden), which may be the finest reason of all to invest in the best plant that you can.


  1. It's the year of the peony here in the Inland Northwest, too. We had an odd, early spring and the peonies are already finishing their bloom; they are usually blooming on the 4th of July here. They have all had huge numbers of blooms. (mine are all herbaceous- too cold here for tree peonies, sadly.)

    I keep hoping for the insanely fragrant peonies I've sniffed in some old gardens; sadly, it seems that the current owners never know what they are (they were already in place when they bought the property) and so far I've not been lucky enough to be offered a division of any of them....

  2. john in cranston5:08 PM

    This season HAS been a good one for the peonies, and I have been assuming that they have benefited from the lack of storm. Or at least I have benefited: Mine have been in for 5-6 years so I assume that the roots are established and not hurt by the dry spring. But that dryness has meant for a long season of being in bud, followed by a long season in bloom- no downpours to knock them down. They are just now losing their petals after the past couple mid-80's days.
    The one problem that I have encountered is "bud blast". The plant leafs out, the bud form, gets as larges as a marble or so, them dries and is absorbed back into the growing foliage.
    Pretty disappointing.
    I never compost the leaves from peonies, afraid that the pathogen won't reliably die off. This year it only impacted one of my 5, and that one was situated solidly in the number 2 slot of three in a row.
    Very weird.

    Ok, now let's have some rain already...

  3. I love that shot of the tree peony with the bamboo support! Tree peonies are by far my favorites, although I like all peonies. The ones I have had growing up in Michigan and at my parents' place there now never needed any winter protection, though it does take a few years for them to settle in and flower well. In a lot of little-tended suburban yards in my parents' are they often seem to be the only really nice thing still growing and blooming years after the people who originally planted the garden have moved out or gotten to frail to tend to the garden.

  4. Anonymous10:14 AM

    dear matt,
    "plant boy" has a very sweet and grave expression!
    are any of the peonies at your place 'Edulis superba' or 'Mons. Jules Elie'? photos?
    have an unknown heritage from long-lived garden we work in. lactiflora, not colossal, fragrant, pink crown petals with center petaloids pink aging paler. increases rapidly.
    all best,
    ~ 02568

  5. The yellow bartzella is just so lovely. I really want to see it grow and bloom in my garden but I heard that it's only suited in cool climates. Do you think it can grow well in a warmer area?

  6. Peonies Envy very good. Gave presentation at our Garden Club and I purchased woodland variety. Healthy, spreading wildly and beautiful!!!


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