Paeonia japonica. P. obovata

James Waddick
Mon, 21 May 2007 06:29:15 PDT
>P. japonica has been described as being diploid, P. obovata as being
>tetraploid (in The Peonies edited by John Wister); Allan Rogers in Peonies
>lists both as diploid.

Dear Jim and all,
	There's some folks who consider these as two species, others 
as variants (P. obovata obovata and P. obovata japonica. They are 
obviously very close.
	P. japonica are always diploid (2n=10), but at least wild 
populations of P. obovata contain both diploid (2n=10 ) and 
tetraploid (2n= 20) individuals.
	I suspect most cultivated plants are tetraploid selections 
because -see below -

>  I grow P. japonica, but I do not grow P. obovata. The plants of P. obovata I
>have seen seem stouter than P. japonica as I know it.

	Yes cultivated P. obovata are stouter, larger plants about 
1/2 again as big as P. japonica. They also have greater 'substance' 
in their flowers and foliage.

>  Also, P. obovata gets its name from the relatively wide, blunt terminal
>leaflet (Wister again); P. japonica as I know it has relatively long,
narrow, pointed leaflets.

	This is not terribly useful as there is lots of variability.

	Seen individually they can be hard to separate. Seen side by 
side they are distinct and with experience you wouldn't confuse the 
	And with LOTS of generalization:

	obovata to 30 inches with larger more substantial parts. Wild 
plants can have pink or white flowers, although usually white flowers 
are seen in cultivated plants.

	japonica to 20 inches . Plants are slimmer, more delicate 
than above. Flowers white.

	Both have been touted as peonies, for shade, but they both 
decline in deep shade. They need half shade or a few hours of dappled 
sun to do best.

	As a larger showy plant, P. obovata makes a bigger specimen, 
while P. japonica is more suited to a shaded 'wild' garden.
	So obovata looks like a cultivated garden plant to most, 
while japonica might look like the smaller wild flower sort of 

	And finally, Jim you should grow both as they do well in your 
area. "Chanticler' (sp?) gardens S. of Philadelphia has a great 
planting of P. obovata.

			Jim W.
Dr. James W. Waddick
8871 NW Brostrom Rd.
Kansas City Missouri 64152-2711
Ph.    816-746-1949
Zone 5 Record low -23F
	Summer 100F +

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