Double Play Spirea: More Than Just Pretty Flowers

As a general rule, Spiraea is known as a hardy, adaptable, and attractive ornamental shrub. And of the 90 different Spiraea species, few are as colorful and useful as Spiraea japonica. The species is very hardy, adaptable, and offers a wide range of flower and foliage colors. Add to this the ability to cross with other species, and you have an array of breeding opportunities. With Spiraea, as well as other species, observation and imagination are the first steps in plant breeding, so looking for and noticing things that others may miss brings new opportunities.


One of our early discoveries was a rich, pink-flowered Spiraea fritschiana that we named Pink Parasols® (‘Wilma’). Known for its excellent hardiness and attractive autumn foliage, Spiraea fritschiana is a low-mounded Korean native with large, attractive blooms that are normally pure white. By pure luck, I found this pink-flowered anomaly in a batch of seedlings at a local university. The seed source of this plant originated in Korea, and I suspect it might have been an accidental hybrid with Spiraea japonica. Pink Parasols is a low-mounded plant that is much wider than it is tall, making it an excellent commercial landscape plant. 

Another observation we made early on was that most spirea are sold in the spring, well before the flowers appear. This means that the color, texture, and health of the foliage is how most consumers judge the plants they are buying. Further observation revealed that some seedlings had especially good, colorful foliage when leafing out in the spring. Such was the case when we crossed Pink Parasols Spiraea fritschiana with a yellow-leafed Spiraea japonica variety and came up with a number of unique, colorful hybrids. After evaluating the top selections, we introduced one and named it Double Play Big Bang® (Spiraea x ‘Tracy’). The spring flush of foliage is a vibrant orange. As the foliage matures, it turns bright yellow with contrasting red new growth. The pink flowers are extra-large, getting this trait from Spiraea fritschiana. The plant cultivar was named in honor of my wife, Tracy, and has proven itself to be a first-class garden and landscape plant. Thank goodness for that, because you don’t want to name a bad plant after your wife!

Double Play Big Bang



It is amazing to note the difference in flowering between cultivars as well as seedlings. Some plants only flower at the top while others flower from top to bottom. The corymb (bloom) diameter varies greatly between plants. The green-leafed varieties, Double Play Pink (Spiraea j. ‘SMNSJMFP’) and Double Play Artisan® (Spiraea j. ‘Galen’) were all selected for large corymbs and bloom density from top to bottom, having pink and purple flowers, respectively. Both cultivars are especially attractive in early spring as the new foliage emerges burgundy-red. 


Trialing is one of the most important parts of plant breeding. Double Play Artisan stands out from the crowd.


Double Play Red® (Spiraea j. ‘SMNSJMFR’) has beautiful cherry-red spring foliage, but is was primarily selected for its uniquely colored, sangria-red flowers. It is the truest red I have ever seen in a Spirea; better than ‘Dart’s Red’ and far better than ‘Anthony Waterer.’ As the flowers age, the dark red hues do transition to pink, so there are times when the flowers will look more pink than red. Regardless, it is a truly unique and beautiful plant. 


Double Play Red (on the right) is the first true red spirea

Many gold-leaved cultivars being grown in the nursery trade are susceptible to powdery mildew (Podosphaera spiraeae). Double Play® Gold was introduced as a solution to this problem. Double Play Gold (Spiraea j. ‘Yan’) is a compact, dwarf, gold-foliaged plant adorned with bright, bubblegum pink flowers. 


Double Play Gold


While most of the plants in the Double Play series were developed by Spring Meadow in our internal breeding program, two varieties were developed by North Carolina State University. A number of years ago, we had funded Dr. Thomas Ranney’s plant breeding team to develop sterile cultivars of potentially invasive plants. 

One of the common methods for sterile varieties is to create a triploid (3x) plant that has three sets of chromosomes instead of the normal two, a diploid (2x). This was the technique used to create seedless watermelons. The process starts by treating young seedlings with colchicine or oryzalin, which doubles the chromosomes, thus creating a tetraploid (4x) plant. The tetraploid plant is then crossed back with a normal diploid plant. The resulting triploid seedlings are often seedless. Double Play Doozie® (Spiraea japonica ‘NCSX2’) is a seedless triploid, as well as a wide cross containing genes of more than one species. One of the added benefits of seedless plants is that they put their energy into flowering instead of setting seed. With Double Play Doozie Spiraea, this results in a spirea that flowers all summer long. 


Double Play Doozie spring foliage

Double Play Doozie the first ever continuous blooming spirea


This plant is a game changer in the landscape market because it is so easy to grow and because it looks just as good in flower in August as it does in June when it first flowers. There is no need to shear it to get it to rebloom. The new growth continues to produce flower buds and flowers that cover and hid the older flower heads. The flowers are a vivid dark pink making it the perfect plant to replace ‘Anthony Waterer,’ a variety that should have been discontinued year ago because it is a virus infected cultivar.  

Double Play Candy Corn® (Spiraea japonica ‘NCSX1’), is another Tom Ranney triploid hybrid, but it is not noted for being a rebloomer. This plant variety was selected for its unique, colorful foliage. In the spring the first flush of foliage emerges a fiery orange-red. As spring progresses, the foliage color changes to a bright yellow and then eventually to a butter yellow, while constantly being accentuated with bright reddish-orange hues in the new growth. The color combination is quite unique and pleasing. The name Candy Corn, pays tribute to a sickeningly sweet American Halloween candy noted for its bright orange and yellow colors. 


The foliage transition of Double Play Candy Corn 


There is one more spirea in the Double Play series that is not a Spiraea japonica, but rather a selection of Spiraea media, a species that is native to Eastern Europe. A number of years back we used to grow and sell a Darthauzer nurseries variety named Snowstorm™ (Spiraea media 'Darsnorm'). After three or four generations of inbreeding and selection, we singled out a dwarf plant with notable blue foliage. We introduced it with the name Double Play Blue Kazoo (Spiraea media ‘SMSMBK’) a silly but memorable name based on the silly children’s musical instrument. I love plants with colorful foliage, especially blue foliage, and I believe this is a special plant. It is a low-mounded beauty with waxy, blue-green foliage that is randomly airbrushed with a cast of purple hues. The large, white, spring blooms contrast wonderfully with the richly colored foliage. Like all spirea, it looks best when planted en masse.


Double Play Blue Kazoo foliage

Blue Kazoo planting in bloom


It is a bit humorous looking back, because so many people told us we were wasting our time breeding Spiraea. They said, “Who needs another spirea?” But like all plant breeding, there is always room for new plants if they are improvements. Growers continue to look for plants that finish faster and that have fewer production inputs. Retailers, with a limited number of salespeople, are looking for plants with greater impulse appeal, which will sell themselves. Consumers want shrubs that offer more than just two weeks of flowers. They are looking for reliable plants that earn their keep all season long, and these new spirea do just that.

  

Get more information on each of the Double Play varieties here. 



Taming Invasive Species

It is welcome news that lawmakers and the public now recognize the threat of certain exotic species that can displace our native species and alter our native ecosystems. Gardeners, nurserymen, landscape architects, and other land stewards need to act responsively to preserve our native habitats. No one wants to be responsible for the next purple loosestrife, kudzu, or multiflora rose, all well-known examples of problematic species. The proverbial Pandora’s box has been opened, and now the question is how to close it.

Lawmakers have been scrambling to solve the problem of invasive plants. Banning plants deemed invasive has been the main tool utilized thus far.  For example, the Ohio Department of Agriculture has just banned 38 species of plants. Banning these weedy, seedy plants should please environmentalists and gardeners alike because most have no commercial or ornamental value. But how do we address plants that do have horticultural value? 

Plant scientists, horticulturists, farmers and gardeners have been breeding and selecting cultivars since the dawn of agriculture. Historically, cultivars have been developed to produce greater crop yields, larger fruit, and bigger, more colorful flowers. But they have also developed breeding techniques to create seedless plants. We're all familiar with seedless oranges, seedless watermelons, and seedless bananas. So why not create seedless ornamental plants to solve the invasive plant problems? Researchers are doing just that! 

North Carolina State University researchers have been at the forefront of taming invasive species. Dr. Dennis Werner developed the Lo & Behold® series of butterfly bush (Buddleia), which was granted an exemption in Oregon, where Buddleia has been banned because of its evasiveness in the Pacific Northwest. 

Black Knight butterfly bush (left) and Lo & Behold Purple Haze (right) 

Dr. Thomas Ranney, another plant researcher at NSCU, has developed two seedless cultivars of Japanese barberry (Berberis thunbergii). One of the cultivars, Sunjoy® Mini Maroon, produces fruit, but just like navel oranges, the fruit contains no seed. Sunjoy® Toto, another dwarf, dark-leafed selection, does not produce any fruit at all. Both Sunjoy® Mini Maroon and Sunjoy® Toto are perfect replacements for the purple cultivars of barberry that have been shown to be invasive in the Northeastern United States.

The fruit of Sunjoy® Mini Maroon barberry contains no seed, rendering it noninvasive.

Sunjoy® Mini Maroon—the environmentally friendly barberry. 



Comparison of female fertility traits among cultivars of Berberis.
Cultivar
n
Fruit Set
Seeds
Fruit
Germination
Seedlings
Flower
Relative
fertility
 10
 0.3 B
0.10 B
 0.0 B
 0.0 B
 0.0 B
Sunjoy Toto ‘NCBX1’
 5
 0.0 B
0.00 B
 0.0 B
 0.0 B
 0.0 B
‘Golden Devine’
 5
 33.8 A
1.15 A
 38.3 A
 0.16 A
 71.3 A
 8
 42.7 A
1.26 A
 41.1 A
 0.22 A
 100.0 A
2014
 10
37.4 B
 0.09 B
23.3 B
0.003 B
 1.2 B
 4
 66.0 A
 1.30 A
 30.3 B
 0.284 A
 100.0 A
 8
 33.5 B
 1.13 A
 56.4 A
 0.220 A
 77.6 A
ZRelative fertility = seedlings/flower of that cultivar divided by seedlings/flower for the highest cultivar measured that year x 100.  Means followed by the same letter, within a column, for a given year, are not significantly different, P<0 .05="" a="" anova="" based="" font="" means="" on="" separation.="" waller-duncan=""> 
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Cultivars such as these have the potential to, in part, solve the invasive plant problem, but in some cases states are banning them along with the culprit species. It’s frustrating because plant breeders are addressing this issue, and their work is going to waste because people are simply uneducated. Legislators are throwing the baby out with the bathwater. 

At the moment, few people seem to care about the cultivar issue because they don’t know that environmentally safe, seedless cultivars exist. Gardeners, like environmentalists, are proud of our natural heritage and want to preserve native habitats. They want to do what is morally right, but they also want to create beautiful gardens in our man-made habitats. Cities and suburbs present challenging growing environments, and some plants perform better than our native plants. 

There are others who do know about non-invasive cultivars and are content to keep quiet because they’re not gardeners and they don’t want to complicate the invasive plant issue. Their goal is to keep the process moving. And the process is moving fast. The question is, will gardening public wake up and smell the roses? Perhaps, but it may be too late to make a difference, as states continue to ban environmentally friendly cultivars.

Gardeners and growers are not the bad guys, and they need not be the losers. Non-invasive, seedless cultivars are the answer and not the problem in the complex issue of invasive species.