On the Road Again

It's that time of year when I go out and about giving plant talks. I thought I would give you an update on when and where I will be speaking. In other words this post is an unabashed attempt at self promotion so that my audience will be greater than six people (it's happened). 

You won't have to travel far to hear me speak on behalf of the WNLA as I will be presenting a Webinar on Wednesday November 28th at 1:00 pm eastern / 12:00 central time. Join me as we explore the impact of boxwood blight on the future of the nursery and landscape industry and as we take a look at some of the best alternative shrubs that can fill the same niche as box. Sign up Today.

 What will become of this family of boxwood?  

Not just one plant geek, but twelve all in the same room

Please join me at the SNA Conference in Baltimore on Tuesday, January 8th. I will be presenting a new talk called "Breakthrough Plant Breeding in Flowering Shrubs." where we will explore a series of unique plant introductions that have changed the way we garden and landscape.Cool stuff right?  

The SNA Conference is a two day, rapid fire plant geek fest just before the MANTS show, so come a bit early to hear the greatest line up plant geeks every assembled. If not for me, come and hear Buddy Lee "the inventor of Encore Azaleas," author and plant geek Paul Cappiello, Mr. Tree Man himself - Keith Warren, Natalia Hamill - the First Lady of new plants and your Ragin' Cajun plantsman extraordinaire Todd Lasseigne. It is a must attend event for all plant geeks, so be there, or be normal, it's your choice.  

A bit closer to home, I will be giving a talk in Lansing, Michigan at the  2019 Great Lakes Trade Exposition.  

"Shrubs that Will Change the Way we Landscape" is the title of the talk I will be presenting on January 29th at 4:15 pm. 

It used to be that shrubs were the bones and background of the garden. They were big plants, that bloomed for two weeks or less and then they faded into oblivion. All that has changed. Plant breeders the world over have reinvented the shrub and with that, the way we used them in our gardens and landscapes. This talk will highlight some of the most interesting breakthroughs in plant breeding and how designers can use them to make better gardens and landscapes. 

Oh So Popular!

One plant at a time, Proven Winners has become oh so popular!

On February 7th I will be speaking in Cincinnati, OH at the 2019 Tri-State Green Industry Conference.  The Tri-State Green Industry Conference is a collaborative effort between Ohio State University Extension, Purdue Extension, University of Kentucky Extension, Cincinnati State Technical and Community College, Spring Grove Cemetery and Arboretum, Boone County Arboretum and the Cincinnati Zoo and Botanical Garden. Whoa - that's a lot of collaboration!

The title of my talk will be "Proven Winners - What has driven our success." The topic was suggested by my friend Scott Beuerlein of the Cincinnati Zoo. I've not yet written the talk, but I think it will be interesting. Proven Winners has a remarkable story and I am fortunate to have been a part of its growth and evolution. You'll have to attend to find out if the talk is any good or not. Click here to learn more.  

MSU - The birth place of modern horticulture

My good friend Mary Wilson of the Michigan State University Extension Service is a badger (a Wisconsin Badger). She insisted that speak at her Plants of Distinction conference in Novi, Michigan. How could I say no? Rumor has it that David Culp and my friend and fellow Spartan Matthew Ross of Longwood Gardens will me join me on February 13th for this event. If you are in the area come on over and catch my talk "The Hunt for New Hydrangeas." You'll everything and more about Hydrangeas and how to grow them. I hope to see you there!

That's me in a wild patch of Hydrangea in Japan

Last, but of not least, I will be appearing at the Devos Place in Grand Rapids, Michigan on Saturday March 2nd. My friend and fellow Spartan Rebecca Finneran booked me for the Michigan State University Extension Smart Gardening Conference. How could I turn down the nicest person in horticulture? I will be speaking about "Smart Shrubs", the ones that make our lives better, easier and more joyful. Better than an iPhone, these smart shrubs will amaze you, so mark you calendar and join me in Beer City USA for this special event. 

Have a great Thanksgiving holiday! We all have so many reasons to be thankful. I am especially thankful that I work in such a great industry, with such friendly and interesting people. Plant people are special. They notice and appreciate the small miracles that happen all around us, every day. I am also very grateful and appreciative to those of you that read my blog. Thank you and thumbs up to you my fellow plant hunters!     

Two thumbs up plant talks

Pretty. Powerful. Pink Annabelle Hydrangea.

Unfortunately, we all know someone who's been touched by breast cancer. For me, it was my mom. I was about twelve or thirteen years old when she was diagnosed, and back in the early seventies the treatment options were not all that good. She survived, but it changed her and changed me as well. So when I found the opportunity to help fund breast cancer research through my work with Proven Winners, I was all in. I saw it as a great opportunity to get the entire nursery and garden center industry involved in a cause worth supporting. It's Pretty. It's Powerful. Take a moment and watch this video.  

Thank you for watching the video. Now ask yourself what you can do. It might be as little as sharing this blog post with your friends on Facebook, buying your mom an Invincibelle Spirit II hydrangea, or making a small donation to the Breast Cancer Research Foundation.

Or it could be something bigger. You decide. Individual actions can grow and become pretty...powerful. 

More about the campaign at InvincibelleSpirit.net 

Boxwood Alternatives

Boxwood, because of its functionality and deer resistance, is one of the most utilized landscape plants in the world. Unfortunately, boxwood blight, a lethal disease caused by the fungus Calonectria pseudonaviculatum, is threatening this iconic shrub. The disease, well established in Europe, has crossed the big pond and is now killing boxwood in North America. 

In the fall of 2011, boxwood blight was detected in North Carolina and Connecticut. Since then, it has been found in Alabama, Delaware, Florida, Georgia, Kentucky, Kansas, Massachusetts, Maryland, Missouri, New Jersey, New York, Ohio, Pennsylvania, Oregon, Tennessee, Virginia, and West Virginia. The fungus is spread by the transport of infected plants, and from infected plants to healthy plants via hedge shears, animals, and human touch. It is a slow but methodical spread that continues to widen. With that spread, plant breeders and researchers have been working to solve this problem.

One of the simplest solutions is to use alternative plants that have the same utility as boxwood but are unaffected by the disease. Two species that have the greatest potential to be suitable boxwood substitutes are Ilex crenata, Japanese holly and Ilex glabra, inkberry holly. Both have small, broad, evergreen leaves and dense branching that responds well to being sheared into hedges, globes, and spires. 


Inkberry or inkberry holly is an Eastern North American native evergreen that is hardy in zones 5-9. Typically it is a large plant maturing at 5 to 6 feet in height. It grows best in moist acid soils, but is adaptable to most average garden soils. Rutgers University lists it as moderately deer resistant, being seldom severely damaged by deer. There are a number of cultivars on the market that are more compact than typical; however, most have a tendency to lose their leaves on the lower portion of the plant with age. Recently two new selections have been introduced that look and behave much more like boxwood.

The first selection is called Gem Box® Ilex glabra 'SMNIGAB17'. This plant was developed at Spring Meadow Nursery. Hundreds of seedlings were grown out and field evaluated over a ten year time frame. Any plants that developed bare stems were eliminated from the trial. In addition, plants that had winter burn or that were damaged by snow load were also destroyed. With time, and the destruction of many plants, about a dozen individuals were selected, propagated, and trialed again both in containers and in the field. The very best of these plants was eventually chosen and introduced in the spring of 2015 under the name Gem Box. The demand for Gem Box was so large that Spring Meadow had to hold off a year on shipping to build up a larger stock block. In 2016, thirty thousand plants were shipped to growers. By spring of 2018, the sales jumped to just under 100,000 plants, and a good number more could have been sold if only there had been more plants. Obviously, there is a huge demand for a good boxwood alternative. 

Gem Box® inkberry has extremely dense branching, small glossy leaves, but most importantly, it retains its lower foliage, making it an excellent replacement for boxwood. In the spring, with the initial flush of growth, the foliage exhibits an attractive cast of reddish-burgundy coloration. In the spring, if you look closely, you will find that it has small white flowers, and if you have a male pollinator near by, you will also get small black fruit later in the summer. Neither the flowers or the fruit are very noticeable. While the plants are naturally dense and rounded in habit, it responds wonderfully to pruning and can be sheared in globes or hedges with round or squared off edges. 


This spring, another inkberry boxwood substitute will be available to growers. This selection, called Strong Box® Ilex glabra 'Ilexfarrowtracey', was developed by Mike Farrow of Maryland. We trialed this variety in our test field for over five years and we were very impressed with its dense habit, dark green foliage, and superb winter hardiness. It has larger leaves than Gem Box® and a more mounded habit, making it quite distinct. The foliage is thick and dense even on the lower branches. 

And now for something completely different: Juke Box® ×Pyracomeles is one of my favorite boxwood alternatives. This remarkable new broadleaf evergreen could easily be mistaken for a boxwood. 

Juke Box® sheared into a ball looks a lot like a boxwood

This new plant comes without the threat of boxwood blight because it is an intergeneric hybrid between Pyracantha and OsteomelesIt had no thorns, no flowers and like a boxwood, can be sheared and shaped as desired. It reminds me of a 'Morris Midget' boxwood but with much faster growth. This new plant comes from Dr. Tom Ranney of North Carolina State University.


When left unpruned, it forms a thick, mounded evergreen mat, but with a little bit of shearing, it can be formed into a ball, box, or a low hedge.

Initially I did not think this plant was going to be hardy in Michigan and based on the parents, I listed it as a zone 7 plant. We have now overwintered it successfully in our test field for three years and it has not missed a beat. It is certainly hardy to zone 6 and perhaps zone 5b. 

While plant pests and diseases can be disruptive, they can also force us to think creatively and can bring new opportunities. There are so many beautiful and useful plant species in the world, so we have lots of choices. When it comes to replacing boxwood these three selections fit the niche. 

Well, I've got to catch a plane to England. So many plants and gardens to see. I'll let you know what I find when I get back. Cheerio!  


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.     

Russian Hardy

I recently had the opportunity to speak to the Russian Nursery Stock Association at their annual conference in Moscow. This is the second time I have spoken at this conference and the attendees were once again eager to learn about new flowering shrubs that are hardy enough for Russian winters. 

The winters in Moscow are very cold and similar to what we experience in Michigan. It has a continental climate so they get plenty of snow and have unpredictable spring weather. Of all of the plants that I spoke about at the conference, the Invincibelle® line of Hydrangea arborescens drew the most attention. In Russian they have the same issues with Hydrangea macrophylla that we have, losing their flower buds and failing to flower. So having a broad line of winter hardy, reliable blooming hydrangeas was good news to the Russians (as it is for most of us in the US and Canada). 

This last year Proven Winners introduced three new hydrangeas in the Invincibelle® line bringing the total to five unique shrubs with an expanded color range of mauve, green, white, pink and red. The series offers a number of dwarf sized plant sizes starting at two and a half feet tall and a few plants that reach four to five feet in height. Add to that three additional varieties of Hydrangea arborescens, the Incrediball® series and Lime Rickey®, and you have eight hardy hydrangeas that can easily handle the worst Moscow winter. If you live in a climate where Hydrangea macrophylla flowering can be hit or miss, this is welcome news. If you own a garden center and you are tired of dealing with customers complaining about their hydrangeas not flowering, this is great news. Here is a synopsis of the hydrangeas I shared with our Russian cohorts at the APPM conference.

Invincibelle Limetta®

One of my favorites, Invincibelle Limetta® hydrangea has a unique short stature with iridescent green flowers from head-to-toe. It was a standout in our test field garnering attention from everyone including Rosie our nursery dog. It glowed in our trial garden where we planted it as a low border hedge, showing off its design value in the landscape. In full sun, particularly in the South, the flowers will transition to white before aging to dark green.    

Rosie knows how to pick out the best plants

Invincibelle Limetta® as a low border hedge in our trail garden

Excellent flower coverage makes this plant a standout!

Invincibelle Mini Mauvette®

There is a lot to like about Invincibelle Mini Mauvette® hydrangea. The mauve colored flowers are a major breakthrough. The color varies depending upon the age of the bloom. In bud the flowers open a rich purple and lighten as the flowers mature. Eventually, the flowers age to a blue-green dusted with shades of purple and red. The leaves and stems have a very strong substance to them, keeping the plant neat and tidy throughout the summer. Its dwarf, compact habit make it a good companion with Invincibelle® Limetta, Ruby and Wee White.

Invincibelle Mini Mauvette® unique flower color

Strong stem strength makes Invincibelle Mini Mauvette® an excellent garden plant

Blooms age to a blend of green, purple and red

Invincibelle® Ruby

Dr. Tom Ranney knew he had a winner when it first saw Invincibelle® Ruby in bloom in his breeding field. This dwarf, compact selection brings us another color breakthrough in Hydrangea arborescens. Dark burgundy-red buds expand in mid-summer and mature to a rich reddish-pink. The undersides of the petals remain dark while upper side lightens to pink giving the blooms a two-toned contrast. Eventually the flowers lighten to pink and change to green. Invincibelle® Ruby hydrangea has been a standout plant in our test field and our trial gardens. 

Dr. Tom Ranney admiring the original Invincibelle® Ruby 

The unique flower color is a first.

Invincibelle® Ruby in our trail garden in Michigan.

Invincibelle® Spirit II

Even though Invincibelle® Spirit was a breakthrough plant, being the first ever pink Annabelle-type hydrangea, it did have its problems. It did not look good in a container at retail and it took a few years in the garden to build up a body. Invincibelle® Spirit II has solved these issues and gives us even richer flower color. The foliage is also darker and more substantial and the blooms age to a pleasing, rich green. This is a big, bold plant that makes a statement in the garden. It has been a performer in our test field and in our trial garden. And like the original, which it replaces, $1.00 per plant sold supports breast cancer research.   

Version 2.0 has stronger stems and richer flower color.

Invincibelle® Spirit II - a standout plant in our test field.

Improved flower color with version 2.0.

The aged, green blooms are are another improvment.

Invincibelle Wee White®

Normally, white flowered shrubs don't get people all that excited, but Invincibelle Wee White® breaks all the rules. The smallest of all the plants in the series, this little beauty is a button of blooms. The flowers start out a soft green then change to white, occasionally showing a whisper of pink just to make things interesting. Year after year, this plant shined in our test field and drew lots of attention in our trial garden. Based on our trials and initial sales, you're going to be seeing a lot of this plant in landscapes near you.    

Blooms all the way to the ground.

The smallest of all the Invincibelle® selections.

Invincibelle Wee White® flowers will at times show a touch of pink and green.


While Incrediball® hydrangea is not a new plant, it is new in Russia. Again, despite being white, this plant has defied all sales expectations. The numbers just keep going up and up, year after year. I think that consumers are just getting to know this plant. Skeptical at first, people that have grown Incrediball® hydrangea have come to be true believers. As an example, two years ago I gave a talk at the International Hydrangea Conference on Cape Cod. During the conference there was a thunderstorm. Afterwards, when we visited the garden, a bed containing both Annabelle and Incrediball made everyone at the conference believers, including Dr. Michael Dirr. The Incrediball® hydrangea was unfazed, while Annabelle, planted right next to it, was a twisted wreck.    

Incrediball® continues to grow in popularity. 

An Incrediball® flowering hedge in our trial garden.

Incrediball® Blush

For some people, the bigger the better. And just like Incrediball®, Incrediball® Blush has really big flower blooms. This is a fulled sized plant with large, silver-pink flowers held high on super strong stems. As you can see below, Incrediball® Blush was a stand out plant in our test field. Even after a number of rain storms these plants looked great. The flower buds open a rich pink and then take on its silver-lavender-pink coloration as the blooms mature.  

Incrediball® Blush a standout plant in our test field.

Big silver-pink blooms on super strong stems.

Lime Rickey®

This plant was a late save. Initially we did not put it in the Proven Winners program because we knew we had a green flowered hydrangea coming with Invincibelle Limetta®. But after watching it year after year in our trial garden we had a change of heart. This plant is definitely Proven Winners worthy. It shines like a beacon in the garden, drawing your eye and your admiration. The contrast between the bright lime-green flowers and dark green leaves adds to it uniqueness and charm.  It stands up to rain storms never missing a beat. The flower heads are not supper big, but that's OK, it just adds to its grace and beauty.  

Lime Rickey® looking good in our trial garden.

A range of green colors delight the eye.

Lime Rickey® hydrangea blooms contrasting with dark green leaves.

I had some extra time after the conference in Moscow, so I took a high speed train to Saint Petersburg for some sight seeing. It's a beautiful city filled with fascinating history and awesome architecture. The people were friendly, the food was tasty and I always felt safe. If you ever have the opportunity to go there, I highly recommend it. Here are a few of the sights I saw. Perhaps they might tempt you into taking the trip. Until next time.

Bronze statue of Peter I

                                                                         Kazan Cathedral

Pushkin Catherine Summer Palace

That's me in front of Church of the Savior on Blood

The Hermitage Museum - former Winter Palace