Comparing Dianthus

Each year in the spring, breeding companies from around the world show off the multiple new introductions at the California Spring Trials. Visitors travel the state stopping at multiple venues to see all of the latest and greatest.

Pacific Plug & Liner has a stop along the tour where we also show off new products and host a variety of vendors; one of the highlights at our stop is the comparison trial we have each year. We like to focus on genera with new breeding developments and a lot of confusing choices for the grower.   After Spring Trials, Pacific Plug & Liner is already thinking of what the following years trial will be, taking input from growers and breeders alike. Plants like ipomoea, lavender and lobelia have been trialed in the past. The plants in the comparison trial come from multiple breeders and are grown side by side in exactly the same way. If we need to move the plants to get more bloom we move the whole group; if we spray, we spray them all. No one plant gets special treatment, so what you see is how each variety grew in comparison to the others in the trial with the conditions we gave them.

For the 2012 Spring Trials, Pacific Plug & Liner chose dianthus for the subject of comparison.   

Breeders Compared

HilverdaKooij: Kahori, Sunflor
Kirin: Garden Spice
Kiwi Flora: Scent from Heaven
PP&L: Cosmics
Selecta: Oscar, SuperTrouper
Whetman: Dessert, Devon Cottage, Early Bird, Double Star, Promotional Line, Scent First, Star

The Setup

Culture: Cold grown and bulked for 17 to 19 weeks. Plants were moved to force into bloom for Spring Trials which was earlier than they would bloom naturally. Higher growing temperatures and supplemental lighting caused some stretch and floppiness on some, but not all, varieties.

Transplant: Rooted cuttings were transplanted between weeks 41 and 43 of 2011.

Environment: Plants were potted and grown outside in Watsonville, Calif., to receive vernalization. Watsonville averaged in the low 60s as a high and in the upper 30s to low 40s as a low during the months the trial was outside. In week 8 the trial was moved into a protected unheated structure to encourage more growth and bloom formation.  Also the covering helped to protect blooms from the cold morning fog and drizzle common in Watsonville at that time of year. In week 10 the trial was moved again to an even warmer location with HID lights to encourage more blooms as nobody wants to see a dianthus comparison trial with no blooms!

Pinching: Plants were not pinched.

Growth Regulators: No chemical growth regulators were applied.

The Results

When we start a comparative trial, we hope to see some distinctive winners and losers. Our dianthus trial was a bit more tricky than usual since we trialed both annual and perennial types. We had to remind ourselves along with others viewing the trials that both were used for different applications. Even with these differences we definitely saw some trends. Again, keep in mind, all plants were treated equally in this trial and we did not pinch or apply any growth regulators.

Series: One thing I have noticed when working with many plant series is the lack of uniformity, whether it be growth habit, size or bloom time — the dianthus trialed showed a similar pattern. A series should be a well-matched group of plants in a range of colors, but with similar habits and growth characteristics. It seems some breeders or marketing companies try to get the range of colors as fast as possible but lose sight of other characteristics that make a series work. In the trial I felt the Sunflor and the SuperTroupers were the best-matched series for the annual types and the Devon Cottage and Early Birds best matched for perennial types.   

Favorites: Of course everyone wants to hear what the favorites were; this is always a hard call to make with so many great cultivars out there.

Growth habit: Because of the scheduling of Spring Trials the comparison trial was moved inside to force bloom. We did not pinch or use any growth regulator and this caused some of the taller varieties to become leggy and floppy. What was intriguing was that some series remained compact. My picks for best compact growth habits under stressed conditions were the SuperTroupers, Oscar and Sunflors.

Flowers: While all of the dianthus trialed had beautiful flowers there were a few that really stood out from the crowd either due to their color or unique patterns. ‘Sunflor Charmy’ and ‘Whetman Starburst’ both have bold patterns that caught the eyes of many; ‘SuperTrouper Orange’ is such a unique color for dianthus that everyone fell in love with; PP&L Cosmics wowed the crowd with wild variegated flowers that are uncommon in perennial types.

Best of Show: In June of 2012 I went through the trials again for one last assessment before I sent it to the dump pile. I picked the best looking of the bunch and came up with several varieties including; ‘SuperTrouper Pink’, ‘Sunflor Charmy’, ‘SuperTrouper Cherry+Velvet’, ‘Kahori’, ‘Star Peppermint’, ‘Star Shining’, ‘Scent First Raspberry Swirl’, ‘Scent First Tickled Pink’, ‘SuperTrouper Butterfly Dark Red’, ‘SuperTrouper Orange’, ‘Scent First Candy Floss’, ‘Scent First Sugar Plum’ and ‘Dessert Strawberry Sorbet’. My selections are based on overall appearance, which included bloom count and growth habit.

With more than 70 varieties trialed one might think, “How can you pick just one for best of show?” This is not an easy task but there was one variety that really stuck out to me as a
well-rounded variety that is suitable for many growers. This seemd to be ‘Kahori’. A new variety from HilverdaKooij, ‘Kahori’ is a ground cover type of dianthus with a single hot-pink flower. This was the first variety to bloom and it is still to this day blooming. ‘Kahori’ is very tidy; the old blooms nearly disappear, allowing for the new blooms to come through strong. ‘Kahori’ takes very well to shearing, this encourages re-bloom. The picture on page 22 was taken in June of 2012 and is of the same pot of ‘Kahori’ that was displayed in March of 2012.

Opportunities Going Forward

While there are always great plants out there, there is still room for improvement. I believe the greatest improvements can be made in the following areas:  

• When releasing a series, all colors need to have similar growth habits, characteristics and bloom times. If this is not the case it should not be called a series but rather a collection of plants with similar blooms in different colors. Nothing will frustrate a grower more than having thousands of plants that should be uniform all coming into bloom at different times or all requiring different growth regulator schedules.• Longer bloom times.

• Better self-cleaning attributes, i.e. no brown buds and better re-bloom.

• Improved heat tolerance and less need for vernalization.

Pacific Plug & Liner is always interested in feedback on its trials, and we are eager to hear what you would like to see in future comparison trials. For the 2013 Comparison Trials we will be featuring heuchera. If you are interested in having your varieties represented please contact us.


Find out which varieties — both annual and perennial types — stole the show at Pacific Plug & Liner’s comparative trials.

About The Author:

April Herring is new product development and marketing manager for Pacific Plug & Liner. She can be reached at [email protected] or 831.768.6319.


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Find out which dianthus varieties stole the show at Pacific Plug & Liner’s 2012 comparative trials.

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