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About Woody Peonies (tree peony)
on this page:  lutea hybrids | suffruticosa | rockii
also see:  Peony Culture | Woody Paeonia Catalog

The 'woody' peonies, often called tree peonies,  are comprised of plants that all have woody persistent stems that continue growth each spring season.  The plants are often called 'tree peonies', but are best described as shrubs.  We categorize them into three basic groups: 1)  lutea hybrids; 2) suffruticosas;  3) rockii hybrids.

Lutea hybrids are a cross between Paeonia suffruticosa x Paeonia delavayi (lutea).  This group is intriguing due to the wide variation in flower colors that are not found in other peonies (white, red, yellow, near orange, sunset/coral blends, lavenders, pinks, dark basal flares etc...).  Flowers can be full double or single in configuration.  Newer hybrids, known as 'advanced generation lutea hybrids' (AGLH) may produce better plant and flowering habits coupled with new flower colors and forms.  The plants tend to be lower growing and more 'shrubby' than other groups of woody Paeonia, with many stems produced from a single plant.  Some are very short in habit and cover a much wider area than their height.  Many of the F1 hybrids have flowers that hang down or face down, but are still extremely beautiful and worthy of growing.  The AGLH plants, in many cases, have higher degrees of fertility and are in demand by hybridizers, as well as gardeners.

Wisconsin winters can be very severe and the woody stems of the lutea hybrids may be lost due to low temperatures.  However, this type of hybrid has proven hardy by producing regrowth from below ground buds.  Many of these buds go on to bloom the same season, thus old wood is not necessary for blooming.  The winter of 2013-2014 produced temperatures as low as -30F at our farm and prior seasonal growth was lost.  We cut our entire stock back to the ground and were rewarded with one of the best growing and blooming seasons in memory, testament to this plant's superior habits.  If grown in warmer climates lutea hybrids do attain greater heights and breadth, due to retention of old wood.

Propagation of this woody plant generally requires that woody scions (stems) are grafted to a herbaceous peony root in late August.  Grafts that are successful generally take another 2 to 5 years to become small blooming size plants.  Some cultivars lend themselves better to division and can be propagated by cutting old plants apart.

Hybridizers such as Lemoine, Saunders and Daphnis produced the foundational plants in which newer programs are based.  More recently David Reath and William Seidl have taken the lutea hybrids to advanced generation status.  Other hybridizers (Roger Anderson, Irene Tolomeo and Don Smith) have used this plant as parental material to produce intersectional (Itoh) hybrids, a cross between lutea hyrids and herbaceous peonies.  Much exploration and continued advancement with the lutea hybrids themselves is likely in our opinion.  Larger flowers, greater flower production, better flower carriage, flower color, stem hardiness, and unique shrub form are all possibilities for further work.

Seed production from lutea hybrids remains somewhat challenging due to fertility issues, but is slowly becoming better in new generations.  Germinating and growing the seed is also somewhat problematic in that they are not easily started out of doors, like many other peonies.   We plant our seeds in doors in damp peat, keeping them warm for three months and then cool for another three months.   Small germinated plants are then moved outside to our field in the spring.  The small plants require a minimum of  three to 5 years to grow before flowering.

Paeonia suffruticosa is a species that exhibits a wide ranging variation due to selective breeding.  This group of plants has been hybridized in China for thousands of years and in Japan for hundreds of years.  The Chinese plants are typically not well suited for American and European climates and soils, but a few may be grown successfully with proper conditions.  Chinese suffruticosas are very beautiful, but they were selectively bred in the rather arid regions of China, something that many areas of the United States does not replicate.  Chinese suffruticosas often have heavy double flowers, but stems do not carry flowers in a highly complementary fashion.  Japanese hybridizers of the species appear to have been more selective in their breeding for plant habit and flower carriage.  Many of the Japanese suffruticosas have large semi-double flowers that are held upright with outstanding carriage.  The Japanese plants are typically easier to grow in American and European gardens, but prefer to be grown on the dry side.  Some European and American hybridizers have also worked with this group and have produced excellent plants that do well in our climate and soils.  Paeonia suffruticosa is the most common woody peony available.

Propagation is the same as for the lutea hybrids.  Seeds are more forgiving and can be planted outside with good success.

Paeonia rockii lineage and/or Gansu-mudan are a hardy complex from northern China which has been extensively crossed with suffruticosa to produce outstanding offspring.  Plants can attain large size over time and seldom are affected by cold winters.  Rockii hybrids are typically very hardy plants with a tall upright carriage and may attain very large size.  Chinese hybridizers have been crossing rockii x Chinese suffruticosa heavily in recent years, producing many new and interesting flowers.  Unfortunately, not all of these Chinese hybrids have proven suitable for the American or European garden, presumably due to dilution of the hardy Paeonia rockii traits.  American and European rockii lineage hybrids have proven to be outstanding growers for us without exception.  Most rockii lineage hybrid flowers are easily identified by their dark basal flares at the center of the flower.  Flowers are often large and striking.  As a bonus, the flowers are generally borne in abundance on strong stems that display the flowers to perfection.  Many hybridizers are working to incorporate lutea hybrids with rockii hybrids to produce even greater variance and beauty, but have thus far proven unsuccessful.

The most well know plant in the rockii lineage group is 'Rock's Variety' or 'Joseph Rock', which has white flowers with dark maroon basal flares.  There is an American form and European form.  Both have been heavily used in hybridizing with outstanding results.

Propagation is the same as the lutea hybrids and suffruticosas.  We've had a great deal of success planting seeds of this plant outside in the fall and waiting another year for the small plants to emerge.  A wait of 5 or more years for seedlings to produce their first flowers is not unusual.  The wait is almost always worth it!

The select seedlings we offer are numbered or garden named plants that Bill Seidl or we have produced in our hybridizing program.  Many of these plants will be registered in coming years and are as beautiful as their officially named parents.  The plants are sought after by hybridizers that breed woody peonies and intersectional peonies.  All three of the above groups may be found in our seedling offerings in a given year and are designated as to type.

Woody peonies are relatively expensive due to slow growth and labor intensive propagation.  We do all of our own propagation and use a very hardy and vigorous rootstock for grafting.  Unlike many grafted woody peony plants available on the market, our rootstock is not adventitious.  In other words, you will not be plagued with herbaceous peony growth from the base of your tree peony!  For more information about the sizes we sell, read our Product Size description.

What we offer in these three groups are plants that have performed well for us in Wisconsin.  We think that you will find these plants to be outstanding additions to your garden or landscape (we use them as well-behaved foundation shrub plantings).  Please use the links at the top of the page to view our offerings.
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