Paeonia

Jim McKenney jimmckenney@starpower.net
Fri, 30 Jul 2004 12:31:09 PDT
At 08:21 PM 7/30/2004 +0200, Jamie V. wrote:


>The Japanese cultivars are normally a
>scion grafted onto a P. lactiflora root stock and they do not originate in
>Japan.  They are a local product in just about every land which sells them.
>This has given rise to a relatively stable group of cvs being available for
>US/European markets.  An important cultural point for the grafted plants,
>even if they were to be Chinese sorts, they MUST be planted with the scion
>well below soil level.  The theory is that the scion should root itself over
>the coming seasons and the lactiflora root-stock will wither and die.

Thanks, Jamie, for the European perspective. I think it's a bit different
over here. When you say 

>They are a local product in just about every land which sells them.

Would that that were true. Although it is true that tree peonies apparently
have been commercially propagated in this country for over a century, the
average tree peony buyer never sees these plants. The plants which most of
us buy are imported from Japan (they sometimes come labeled "product of
Japan"). Furthermore, my understanding is that these varieties originated
in Japan, not in China. Traditionally, the open-centered flower type is
associated with Japanese-raised varieties, and the full double sorts
associated with Chinese and European raised varieties. There must be
exceptions to these generalizations, but again, the average tree peony
buyer doesn't see them. 

When you say:

The theory is that the scion should root itself over
the coming seasons and the lactiflora root-stock will wither and die.

See Wister for stories of the herbaceous root stock reaching basketball
size under the flourishing tree peony. Evidently, it is not necessary to
remove the understock, and it certainly does not die on its own.
Furthermore, I've seen tree peonies in local gardens which have the
herbaceous understock growing right up through them, and neither seems to
be winning. (I play it safe and remove them in my garden).

I dug some of the older tree peonies in this garden and removed the
understock. It was probably a mistake; the plants sulked for years. 

You go on to say:

>An important cultural point for the grafted plants,
>even if they were to be Chinese sorts, they MUST be planted with the scion
>well below soil level.

No doubt about it, this is certainly the conventional advice. But it's easy
to overdo the "well below soil level" business. Remember, with grafted
plants, the early years' growth will depend on the success of the
herbaceous understock. Plant it too deeply and you will set the plant back.
Here's a tip which I think makes much better sense: plant the grafted
plants on a slant so that the herbaceous understock is near the surface
(which is where it is adapted to grow) and at least some of the woody tree
peony is under the ground too, where it will eventually root if you're
lucky. Try to keep at least some of the tips of the woody growth below
ground - that way, when soft new growth emerges, it will be in position to
root. 

About forty years ago, when I was drafted into the Army, I had a pending
order of tree peonies from Louis Smirnow, a then famous supplier. A
neighbor, strictly a corn and tomatoes type, volunteered to plant them for
me when they arrived. I gave him  a quick lesson in tree peony planting,
and told him to plant them deeply; he complied. When I returned home two
years later, I eventually found the by-then dead and partially decomposed
stems six inches down. Be careful: sometimes we get what we ask for!

Jamie, you mention (and pass on the very good observation that they are
marketed under Japanese names) Souvenir de Maxime Cornu and Chromatella. I
grow these, and they are fantastic plants. Souvenir de Maxime Cornu just
celebrated its centenary a few years ago. This is a historically important
plant: evidently, it's the first of the lutea-suffruticosa hybrids. And
it's a reminder of the time when France was the West's leader in peony
culture. So let's thank the Japanese for keeping it going and making it
available to Everyman, but let's not lose sight of its origin. 

Jim McKenney
jimmckenney@starpower.net
Montgomery County, Maryland, USA, USDA zone 7, where there is a tree peony
walk in the garden which gets better yearly.  






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