Native Ninebark - Physocarpus

Physocarpus opulifolius, the Eastern ninebark, is a tough, hardy, adaptable native shrub that can be found growing along the shores of lakes and rivers here in Michigan. According to the USDA, the species can be found growing as far south as Florida and as far west as Colorado. With the exception of native restoration projects, you don't normally see this species cultivated - unless it is a cultivar with colorful leaves.

Physocarpus opulifolius in full bloom spotted while kayaking the Muskegon River 

The native range of Physocarpus opulifolius, Eastern ninebark

If you were to look back about twenty five years into the past, you'd basically have two cultivars of Physocarpus to choose from, both with gold foliage. One was a Dutch selection called 'Dart's Gold', and the other an American selection named 'Nugget'. We have trialed both of these plants in our test garden and while the two plants are quite similar, I have to give the nod to 'Dart's Gold' as the better plant. 'Dart's Gold' has a nicer habit, holds its yellow foliage longer into the summer and has shown less susceptibility to powdery mildew. Powdery mildew can be problematic with Physocarpus, and our test garden has some ideal locations for encouraging mildew and so is a great place to evaluate resistance.

Physocarpus 'Dart's Gold'

Physocarpus 'Nugget'

Roughly twenty years ago, something quite unexpected happened. In Germany, a seedling grower discovered a single Physocarpus plant in his field that had dark burgundy leaves. How or why this happened, nobody knows. The grower shared it with his friend Holger Hachmann, a well-known Rhododendron and Ilex (holly) breeder. Holger put it into his display garden where Gunter Kordes, a German shrub grower, noticed it and recognized its commercial value. Together they introduced it as 'Diabolo', (the German name for child's spinning top). When it was introduced in the United States by Monrovia, the name was changed to Diablo® (cv. ‘Monlo’ PP 11,211) giving a nod to its unique dark red foliage. This was a seminal moment in the world of ornamental Physocarpus. 

Physocarpus 'Diabolo'

Diablo was an instant hit in the gardening world with thousands, if not millions, of plants
sold worldwide. But the story does not end there. Diablo had a few shortcomings that needed to be addressed. First off, it's a very large shrub, reaching 12-15' in height, making it much too large for most residential gardens. It's also susceptible to powdery mildew which turns its dark red foliage into an eyesore. And lastly, it has a tendency to revert, sending up green shoots every now and then. Recognizing both its potential and shortcomings, I crossed this dark leafed plant with a dwarf, green cultivar called 'Nana'. By using the green-leafed 'Nana' as the mother and the red-leafed Diablo as the father, I knew immediately that any burgundy seedlings were true crosses between the two plants. The result was the introduction of Summer Wine® Physocarpus (cv. 'Seward' pp#14821). This selection solved this mildew issue. It reduced the size of the plant down to a manageable six to eight feet, and the reversion issue disappeared. In addition, Summer Wine was blessed with a graceful, cascading habit and abundant flowers produced up and down the the length of the stems. But the story continues.  

 
 

Summer Wine® physocarpus in a decorative container

Around the same time, our friends at Minier Nursery in France planted Diablo in their trial garden next to 'Dart's Gold'. Within a few years, they discovered a chance seedling that was obviously a cross between the two plants. They shared it with us and we introduced it as Coppertina® because of its beautiful, orange-copper foliage.  

Copperina® ninebark

Soon after, others got into the Physocarpus breeding game and scads of Diablo crosses were rushed to market in the US and overseas. Burgundy Star, Center Glow, Angel, Ruby Spice, Red Baron, Royalty, Mahogany Magic, Obsidian, Amber, Black Jack, Barberone, Little Devil, Sweet Cherry Tea, and Raspberry Lemonade are just a few of the cultivars that flooded the market.  Meanwhile, at Spring Meadow, we continued to breed Physocarpus, but for a number of years we introduced nothing. Every time we thought we had unique new selection, powdery mildew reared its ugly head. While the plants looked great at first, after three or four years of trialing, mildew became an issue. What else could we do but destroy the plants and continue to breed? We trialed many of the selections listed above, but they too had mildew issues. To make matters worse, we started getting reports that people were having mildew issues with Coppertina®. 
     
Finally, with time and persistence, we hit the mark. We developed a dark-leafed, dwarf variety with a high level of mildew resistance and introduced it as Tiny Wine® (Physocarpus 'SMPOTW' pp#26,749). This petite ninebark has burgundy foliage, richly colored pink flower buds and attractive red fall color.     

Tiny Wine® ninebark

Tiny Wine® ninebark fall color

Through the same breeding line we were able to come up with a gold version of Tiny Wine® that was naturally named Tiny Wine® Gold (Physocarpus 'SMPOTWG' pp#28,857). What really impressed us about this plant was how well it looked in a container. Most Physocarpus selections do not flower well as a young plant, so you don't get many flowers on a one or three gallon plant. Tiny Wine® Gold is unique in that it flowers like crazy, even as a young plant. 

Field trials of Tiny Wine® Gold inspected by Dale Deppe.

Exceptionally floriferous as a young plant, Tiny Wine® Gold makes a great container plant.

With time, we were also able to come up with a replacement for Coppertina® which we named Ginger Wine™ (Physocarpus 'SMNPOBLR ppaf). It had the mildew resistance that we were looking for and the brightest orange foliage we had ever seen. Add to that orange-red seed capsules and we had a real beauty. 

Ginger Wine® is an improved, orange, mildew resistant variety that replaces Coppertina®

Ginger Wine™ remained mildew-free in our trials

Seed capsule display on Ginger Wine™

Over the years we came up with a number of very beautiful selections with dark black foliage. Some of the breeders we work with also brought us remarkable plants with dark black foliage. We came very close to introducing a few of these black-leafed selections, only to pull them back at the last minute due to mildew issues. It seemed like the darker the foliage, the greater the susceptibility to mildew. This could be the case, or it could be that the back foliage make it easier to see the light grey mildew infections. Regardless, the hunt for a good black-leafed ninebark was a lot like searching for a unicorn. Pretty much impossible!  

Evaluating for mildew susceptibility and resistance is essential.  

After growing out and destroying hundreds of potential black-leafed plants, we had pretty much given up on the black unicorn. But finally we found it. Summer Wine® Black will be introduced to the trade this spring. It is a compact plant with attractive, dark black, glossy foliage. It's not a strong blooming plant, and so it will be grown primarily for its dark, glossy foliage and compact habit. While this plant is not immune to mildew, for dark plant varieties it is the best yet. Like all dark leafed Physocarpus, Summer Wine Black should be planted in full sun in locations with good air movement.  

Field trials of Summer Wine Black™.

Summer Wine® Black container trials show clean foliage and a well-branched habit.

I find it fascinating to look back on the journey of Physocarpus from native to ornamental. The story starts in the United States and moves to Europe, but returns home again. What were the odds of finding that one naturally occurring, red-leafed seedling in a field in Germany? I think about all the plant breeders that made hundreds of crosses and sowed out thousands upon thousands of seedlings looking for one worthy plant. I think about the years of trials and testing needed to verify a truly dwarf selection and the time it took to tame the the powdery mildew problem. And now the story comes to our present time. We have a range of really good landscape plants with attractive black, orange, red, and yellow foliage. We have useful dwarf selections in burgundy and gold. Colorful and easy to grow, these new ninebark selections are ready to provide food and shelter for songbirds and season-long color for our gardens. It's been a long and arduous journey, but so much has been accomplished in just twenty five years. I doubt the Physocarpus story ends here. New and better plants will be developed. We are still making crosses and evaluating fields of seedlings. What other surprises are hidden in the genes of this native shrub? Only time will tell.