Reinventing the rose: How to grow beautiful blooms without those pesky chemicals

New York Botanical Garden rosarian Peter Kukielski names his favorite disease-resistant roses.
By Adrian Higgins
Thursday, June 17, 2010

Apart from its beguiling mythology, the rose stands alone in the garden as a shrub that blooms from May until October. And yet today, the rose is spurned like a matinee idol with too many demands and chemical dependencies.

The plant's problems with aphids, beetles and, above all else in Washington, blackspot disease, have relegated roses to the status of outcasts in the eyes of gardeners with neither the time nor the will to fuss with the beast.

But is perception lagging reality?

A decade ago, a breeder named Bill Radler introduced a bulletproof rose named Knock Out, which quickly became the poster child of low-maintenance roses. Since then, the industry has created lines of roses that shrug off blackspot (and mildew) while producing blooms of gorgeous form, size and color.

The romance is back in the rose minus the disease, and the flower has been reinvented.

"We could certainly produce a beautiful plant five years ago with chemical intervention," said professional rose grower Peter Kukielski. "What we are seeing today is beautiful plants without chemical intervention."

Embracing this shift means taking the difficult step of ripping out established and beautiful but sickly roses to replace them with top performers. This is exactly what Kukielski has done with one of the largest and most conspicuous rose gardens along what I call the Eastern Seaboard's Blackspot Alley, at the Peggy Rockefeller Rose Garden at the New York Botanical Garden.

During the past two years, Kukielski has replaced about half of the 3,675 rose plants in the garden with the new generation of bulletproof plants and is ranking them for their beauty, vigor and tolerance to disease and pests. His mission has been made easier by established breeding programs by major hybridizers searching for environmentally sustainable roses. Twenty years ago, Germany was one of the first countries to restrict the chemical arsenal available to home gardeners, and this has spurred much of the hybridizing efforts by European rose breeders.

As jurisdictions here follow suit, the new roses seem likely to play an increasingly important role. New York now bars public gardens from using sprays that are even suspected of causing cancer or affecting child development, a ban that prompted the Rockefeller garden's makeover. "The trend throughout the country is for fewer pesticides," said Kurt Morrell, the botanical garden's director of arboretum, grounds and gardens.

Another emphasis has been in developing rose varieties not just for repeat flowering but also for long bloom life and shorter blooming cycles. The effect is a continual and, in some varieties a continuous, flowering during the growing season.

In the United States, the best-known product of this shift to the bulletproof rose has been the Knock Out rose. A small single or semidouble bloom, in a vibrant -- I might say jarring-- magenta color, it is now one of seven Knock Out varieties, including the soft pink Blushing Knock Out and the somewhat fragrant, buttery yellow Sunny Knock Out.

In France, the House of Meilland, long a pioneer of low-maintenance roses, has developed various landscape and ground cover varieties, notably its Drift series, as well as Romantica varieties that seek to marry the look of old garden roses with a 21st-century resilience. Kukielski is a huge fan of varieties developed by the German breeder Kordes, especially its relatively new Fairy Tale roses.

In his evaluation, Kukielski has produced a list of his top 100 performers, lumping them into three tiers. He has ranked 29 roses as "superior" and 47 as "excellent."

"All were blackspot-free," he said.

Of the top-rated varieties, 15 come from Kordes, including the climber Aloha Hawaii, a red-orange-apricot blend redolent of a classic Kordes climber from 1956 named Alchymist but assuredly more recurrent in flower and freer of blackspot. Kukielski drools over a new variety named Larissa, an upright floribunda type with masses of rich pink blooms that each sport distinct, old-fashioned petal clusters. This A team also includes Lions Fairy Tale, whose blooms are heavily double, a creamy white blushed apricot. Kosmos Fairy Tale is also a blushed white, but with cupped flowers that are moderately fragrant, not the foremost trait in these plants.

Kukielski acknowledges that he hasn't grown many of these varieties for long, but he points out that many have been rigorously tested in 11 trial gardens throughout Germany. In the trials, known by their German initials, ADR, roses are grown without sprays.

The success of Knock Out suggests that the popular view of the rose as a plant too chemically dependent to fuss with is evolving. Common perception, however, has yet to catch up with the advances in roses.

"I think we are on the verge of changing that," said Rahel Berardocco of Palatine Roses in Niagara-on-the-Lake, Ontario. "There's a big opportunity for people to understand that roses aren't a diva."

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