Peter Kolster, owner of Kolster, B.V. in Boskoop, Holland

Nursery Management: Why do global consumers continue to buy and plant hydrangea?

Peter Kolster: Our nursery has been growing hydrangeas since I was 16 years old. We started with garden plants, then got into cut flower breeding. Gardeners love the large flowers and the flower colors. We found that consumers really loved the antique colors (we call them classic colors in Europe) and the hard flowers. We started working with another breeder, Horteve Breeding, who was breeding gift plants. And that’s a market the European consumer really loved. In the U.S. we launched the Everlasting Series of hydrangea. The flowers change colors throughout the growing season and can be shades of many colors, depending on the cultivar. These flowers can also be cut and brought inside and last for a long time.

Revolution XXL
Photo by Plants Nouveau

Everlasting Revolution is a short plant, growing to about 2 or 3 feet high. Consumers can use it in the garden or in a container outdoors or put it in a pot and place it indoors in spring and it still looks good in November. We also found that the Revolution varieties are sterile. Another plus for consumers and growers is that the Revolution plants can grow with less water because of their waxy leaves and flowers.

NM: Which characteristics do you require when breeding hydrangea?

(L-R) Linda Guy (Plants Nouveau) Peter Kolster and Angela Treadwell-Palmer (Plants Nouveau) take a closer look at Everlasting Crimson.
Photo by Plants Nouveau

PK: Before we introduce a plant to the market, we focus on certain traits. The plant must not need support to stay upright, it must have a strong root system and it must have hard flowers. Our hydrangeas are good for the consumer for their looks and garden performance; for the grower because of their root system; and for the retailer because of the long shelf life — with proper watering, of course.

NM: What’s your next breeding goal?

PK: We’re looking at breeding for red leaves, which will make a lovely and unique plant. And we’re looking at hydrangeas that will be suitable in hanging baskets.

Michael A. Dirr, horticulturist, breeder and author

NM: What’s the next big thing in hydrangea breeding?

Seaside Serenade Fire Island
Photo courtesy of Monrovia

Michael A. Dirr: I’ll talk about the next big thing in hydrangeas to anyone who will listen. Remontancy/reblooming opened the floodgates of enthusiasm for H. macrophylla. Every breeder/introducer played the same tune with varying degrees of success. The Endless Summer brand dominates and will for the foreseeable future. Many of the H. macrophylla imports from Europe and Japan were promoted as remontant and have already disappeared from the market. I believe a cold hardy (Zone 4/5) macrophylla that flowers reliably every year would be transformational, whether remontant or not. I know this is possible based on H. serrata genotypes that have flowered with no stem dieback after exposure to -35°F. The two species are easily hybridized, and this was already a goal of our former company, Plant Introductions, Inc. Jeff Beasley, Mark Griffith and I have started a new PII, Premier Introductions, Inc., with the goal of cold-hardy macrophyllas looming large.

H. macrophylla
Photo by Mike Dirr

NM: Why do hydrangeas resonate with the consumer?

MD: Everyone recognizes the brilliant orbs of blue and pink. I posit the question to growers, gardeners and people on the street: When you hear the word hydrangea, what does the mind conjure? Almost always, heavenly blue spheres. Ask the same question about a viburnum and there is no answer.

NM: Can growers continue to capitalize on this crop?

Photo by Carol Reese

MD: Absolutely. At the recent Georgia Green Industry Association trade show, I was told that a major retailer ordered one million Summer Crush for 2021. At present, there is greater focus on hydrangea breeding/procurement in the U.S. than at any time in history. The major nurseries like Bailey and Spring Meadow support hydrangea breeding programs. Monrovia, under the leadership of Jonathan Pedersen, acquire hydrangea genetics from other breeders and build new brands such as the Seaside Serenade series. Southern Living added several H. paniculata selections to the brand. These were developed by Buddy Lee, who has worked almost exclusively with PDSI and Flowerwood Nursery. I am in contact with a private breeder in Virginia who has a boat load of pretty H. paniculata hybrids. There is demand and the breeders are trying to accommodate. The industry has benefited mightily from the advances in hydrangea breeding. There will be introductions never dreamed possible. In fact, scientists in China successfully produced interspecific hybrids of H. macrophylla x H. arborescens with fertile offspring.

Tim Wood, breeder, author and new plant development manager at Spring Meadow Nursery

NM: What breeding breakthroughs should we expect in the near future?

Tim Wood: In my opinion, the next step is moving beyond reblooming Hydrangea macrophylla onto continuous blooming H. serrata hybrids. They have greater stem and bud hardiness so they’re more likely to flower in late spring and summer. This breeding has also brought us plants like Let’s Dance Cancan hydrangea, which seems to flower even without vernalization. Growers can shift up a trimmed quart liner into a 2 gallon and sell it in bloom in about 10-12 weeks. These types of plants should be big winners for growers and consumers alike.

Little Quick Fire
Photo by Spring Meadow

NM: Why does this crop continue to woo both growers and consumers?

TW: The breeding keeps getting better and better. When Bailey introduced Endless Summer, it was a game changer. There were about 100 non-reblooming bigleaf hydrangea varieties on the market, but Endless Summer was just the beginning and now every form and color needs to be transformed into a rebloomer, or better yet a continuous bloomer. Hydrangea arborescens ‘Annabelle’ has been reinvented with the introduction of the Invincibelle series, and now we have five different flower colors and a choice of smaller, dwarf varieties. Who could have imagined this 20 years ago? H. paniculata keeps getting better with the introduction of earlier blooming dwarfs such as Bobo and Little Quick Fire. The new pink and the red flowered varieties are getting better, too. They color up earlier, with richer colors and have improved, stronger habits. Growers will especially appreciate how good these new varieties present and hold up their blooms in a container at retail. Everything keeps getting better.

Let’s Dance Cancan
Photo by Spring Meadow

NM: How can growers continue to capitalize on the crop’s popularity?

TW: Breeders are creating outstanding plants with increased value. Growers and retailers can capitalize on these new plants by embracing change. We can sit around and complain about the pace of new plants, or we can make money selling them. To do that we must have the fortitude to drop the older and weaker growing, less profitable varieties. We do this in the perennial world, and we need to do it in the shrub world, too.