Déjà vu in the garden: Developing repeat bloomers
Growers set their sights on developing repeat bloomers
Robert “Buddy” Lee has been a grower of wholesale plants and a registered nurse over the years, but his one abiding preoccupation has been his need to find a springflowering azalea that blooms through summer and fall.
More than 40 years ago, from his fields in southern Louisiana, this was a lonely quest, but not a quixotic one. As the inventor of the Encore Azalea brand, he has given gardeners more than 30 azaleas in various sizes and bloom color, with more in the works.
“You have waves of color in summer,” he says, “and as it cools down to return to more of the spring temperature range, you’ll get a lot more bloom.”
Lee may have been a pioneer in the desire for a déjà vu
moment in the garden, but he is no longer alone. The ornamental plant industry is defined by a race to develop and trademark plants that keep on blooming beyond their natural moment in the growing year.
“It’s what we are all striving for in every genus,” said Jonathan Pedersen, vice president of sales and business development at Monrovia Nursery, a major wholesale grower. In addition to fall-blooming azaleas, consumers can find hydrangeas that flower in September, sunflowers still going strong in October and even a clematis that produces its bell-like blooms until frost. Roses have always been pushed by breeders to rebloom, but the days of them flushing every eight weeks or so have been replaced by near continuous display.
The floral conveyor belt may upend our sense of a garden’s seasonality, but the breeders, growers and market
ers are confident that homeowners will be drawn to the rebloomers like bees to nectar. They already are.
More than 2.6 million of Lee’s creations are sold annually, and their popularity is squeezing out traditional evergreen azalea offerings.
Garden centers are reducing classic offerings, said Kip McConnell, director of Plant Development Services, which has brought Encore Azalea to market. It works with 70 licensed growers, who also grow ornamentals for others, and many of them have dropped spring-only azaleas in favor of rebloomers, he said. “It’s been a big transition.”
There may be purists who feel a garden is characterized and made more interesting by a parade of blooming plants adhering to their own season, but such a view may not be widely shared.
“Anything that gives gardeners more confidence and gratification is good for the world of horticulture,” said David Roberts, head breeder at Bailey Innovations. “It makes it easier even for a novice gardener to feel successful, and that drives the industry.”
The company is the plant development arm of Bailey Nurseries, which markets the Endless Summer brand of reblooming hydrangeas, represented by five varieties. Since their introduction in 2011, almost 30 million plants have been sold.
Shrubs that bloom in spring, such as azaleas, must get their flower buds through the winter. Summer-flowering shrubs flower from new growth, so the key to developing ever-bloomers is to find plants that do both.
All those years ago, Lee noticed that some azalea varieties had a tendency to flower sporadically in the fall, so he crossed those with a summer-blooming azalea from Taiwan (and many others along the way). The 31 he and
McConnell have introduced were selected from tens of thousands of seedlings Lee has made over the past four decades.
Another way to keep a plant flowering is to give it sterile flowers. Denied successful pollination, it keeps producing blossoms.
A few practical points: Flowering takes a lot out of a plant, so it’s a good idea to give the plants optimal conditions. For azaleas, that means a little shade, organically enriched, moisture-retentive soil on the acidic side and a light mulch.
Some of the reflowering shrubs should be given a light trim after the initial spring flowering. This will encourage the new growth that carries the new flower buds.
More so than with other plants, it’s important that rebloomers be allowed to rest before the arrival of freezes, because if they are in tender growth, they are prone to damage or death. Stop fertilizing by the end of July, don’t prune them in late summer and cut back on watering in early fall.
Azaleas
The first Encore Azalea, ‘Autumn Rouge,’ was introduced in 1997. The series includes dwarf plants (up to 3 feet) and intermediates (3 to 5 feet high), and colors such as red, purple, shades of pink and white.
Spring Meadow Nursery in Grand Haven, Mich., under the Proven Winners brand, produces a reblooming azalea developed by North Carolina State University breeder Thomas Ranney and named ‘Perfecto Mundo.’ It was selected for its compact size, hardiness and resistance to lacebug, said Stacey Hirvela, horticulture marketing specialist at Spring Meadow. A second will be available to consumers in 2021, she said.
Monrovia has five varieties under its Double Shot series. The energy the plant puts into the flowers helps to keep it compact, Pedersen said.
Hydrangeas
We speak here of the eternally popular hortensia hydrangea that blooms late spring/ early summer and is known botanically as Hydrangea macrophylla. Its flowering on the previous year’s wood led to three basic problems: In northern states, it could be counted on to survive but not bloom after a harsh winter, especially without a protective snow cover. In southern states, it was prone to sprout in early spring and then get damaged by a late frost. The third calamity came at the hands of the neatnik gardener, who cut it back in March and removed most of its flowering wood.
The first rebloomer, ‘Endless Summer,’ was launched 15 years ago. The range extends to five varieties, including a lacecap named ‘Twist-n-Shout.’ The latest was introduced this year as a compact red-purple mophead variety named ‘Summer Crush.’
Hydrangea breeders have been focusing on such smaller varieties, which cycle into repeat bloom faster than larger ones. One criticism of rebloomers in northern states has been the endless wait for ‘Endless Summer.’ In addition, breeders are seeking to reduce the wilting that besets hydrangeas in hot climates, Roberts said.
Spring Meadow and Proven Winners have released their own line, under the Let’s Dance trademark. ‘Diva’ is a showy lacecap. The latest introduction is ‘Rave,’ a domed mophead with violet blooms. Hirvela says it’s the best bloomer to date, with other varieties available in 2021.
In its Seaside Serenade series of hydrangea, Monrovia lists seven varieties as repeat flowering.
Perennials
Some may consider bearded irises as a blast from the past, but many of the newer varieties are of reblooming types that put on as much of a show in October as they do in May.
Monrovia offers a repeat-blooming coneflower named ‘Evolution Colorific.’
Proven Winners has its own suite of repeating hardy salvias under its Profusion series, including ‘Rockin’ Deep Purple.’ Walters Gardens has also developed three summer phlox varieties and a catmint named (what else?) ‘Cat’s Meow.’
I can’t leave this topic without mentioning an annual that repeats. Isn’t that what annuals do, you ask?
This is a sunflower named ‘SunBelievable Brown Eyed Girl,’ introduced in North America by Monrovia. Instead of a tall, thick-stalked beast reaching to the sky, it forms a clump no more than 3 feet high and across and is festooned in continually appearing blooms, golden yellow with sterile brown discs. It functions ornamentally as a perennial or even a small shrub, if only for one season.
Monrovia produced half a million in its first year and plans to more than double that for next season, said Pedersen, who brought it over from England. “I feel pretty lucky to have stumbled across a plant like that,” he said. “It’s a blooming machine.”