Knock Out provides a new punch to the garden. It’s a super-vigorous, disease-resistant, repeat-flowering, cold-hardy rose that grows into a head-high shrub inside of two years. Since its introduction in 1988 it has taken the eastern half of the United States by storm, leading millions of gardeners who had ignored or abandoned them to grow roses. In its first year alone it sold 250,000 units, and it has been about as popular ever since. But for all their popularity, Knock Out and its close kin have been ridiculed by the most serious of the rose faithful. Why? Partly because they are not hybrid tea roses, and as such they don’t conform to our expectations for what a rose ought to be. Partly because they have become common, or faddish. Partly because they are not fragrant.
The lack of floral form is probably the biggest hurdle. Entering a Knock Out rose in an exhibition is a little like entering your local Mensa society president in the local beauty pageant, assuming she is a little wrinkled, a little dour, and a tad pudgy. The two are exemplars of very different categories. One exemplifies beauty, the other smarts. Think of Knock Out less as a beauty queen and more as a smart rose, and before long you will get the point.
Knock Out happens to belong to the genus rosa, just as does the perfectly formed hybrid tea or floribunda on the show bench. But it is a rose that takes the shape of a landscape plant. It is about the size and shape of a good rhododendron. In my experience, it grows a good deal faster than a rhododendron. It also blooms more frequently than a rhododendron. But it is happy in brighter light and in drier soil than a rhododendron. So, if you need something like a rhododendron but your site doesn’t work for that, Knockout is a good rose.
As a landscape plant, Knock Out is a smart choice; for three reasons. It produces a lot of interest, it is very durable, and it is vigorous so it reaches its final size fast. East of the Rocky Mountains, one was not able to say things like this about most roses that were in distribution during, much of the second half of the twentieth century. And up until Knock Out’s introduction most people in that area thought of roses as finicky plants.
I tried Knock Out when I grew roses in New Jersey. At the time, most of the new hybrid tea roses I was planting were dying of blackspot. I had just lost Dortmund and Madame Plantier. They had collapsed from a combination of drought and the merest whiff of glysophate overspray. Gloire de Mousseux had recently been imparting fungal infections to Constance Spry, Fantin Latour, and several other roses. Even Carefree Wonder which was not quite killed by blackspot, came perilously close each year. It would be a slight exaggeration to say that my rose garden was a wreck; but I was close to losing confidence in the whole rose genus when I planted Knock Out in the mid 1990s.
Fortunately, I planted Playboy, Sally Holmes, Electron, Buff Beauty, Felicia, and a bunch of David Austin Roses at just about the same time I planted Knock Out. And within three or four years my outlook on rose gardening had changed much for the better. The battles against fungal disease ceased and began to fade in my memory. I grew happy with the idea that there was a group of roses that grew well in my garden.
For me Knock Out serves as the symbol of a turning point in rose culture in the US when the value of a rose planted east of the Mississippi became less predicated on how good it looked when it was photographed in sunny California than on how likely a rose was to survive five or six seasons in the garden covering its full frame for six or eight weeks a year in flowers. Knock Out’s fame may help people in places that have not had roses in their gardens to get started with an easy rose and to enter a world of roses that are of almost as easy care. This new world of easy-care roses takes many forms, colors, and sizes, some quite different from Knock Out.
In other words, Knock Out is a good rose not just for what it is as a rose but for how it brings new people to the practice of growing roses in their gardens. Many will love it for the color it brings to the garden. Others will yearn for roses with prettier flower form or fragrance. What is one to do?
There are several options. If it’s just fragrance you want in a shrub rose, consider one of the hybrid musk roses bred by Joseph Pemberton. Most are quite shrubby, vigorous, tough, and fragrant. Another is to look for roses bred by David Austin. A third alternative, if fragrance is not so important, is to consider the hundreds of good floribunda roses out there. Most are much more durable than hybrid tea roses, but they come in as many colors. Or one might choose a rose from the list below.
- Sally Holmes – tons of white, single blossoms on a very healthy, durable plant.
- Ballerina – tons of tiny pink-blushed single blossoms on a very durable, shrubby plant.
- Prosperity – lots of large white blossoms on a head-high plant, with fragrance.
- Kathleen – tons of single white blossoms with fragrance.
- Cornelia – lots of strawberry colored flowers open to warm pink, with fragrance.
- Gartendirektor Otto Linn – muscular shrub covered with pink blossoms.
- Excellenz von Schubert – muscular shrub covered with pink blossoms.
- Rose de Rescht – hip-height rounded shrub with raspberry colored blossoms.
- Comte de Chambord – waist-height shrub with very fragrant pink blossoms.
- Madame Hardy – shrub bearing fragrant, white old style roses just once a year.
- Carefree Beauty – vigorous head-high shrub, lots of large pink flowers.
- Hawkeye Belle – compact shrub bearing neat pale pink flowers.
- April Moon – shrub bearing pale yellow flowers
- Winter Sunset – shrub bearing pale apricot flowers.
- Quietness – shrub bearing pale pink flowers of old rose form.
- Frau Dagmar Hastrup – shrub bearing fragrant pale pink single flowers, grassy green foliage .
- Therese Bugnet – cold hardy shrub bearing fragrant pink flowers, grassy green foliage.
- Alexander McKenszie – large shrub or climber bearing purplish flowers.
- Alchymist – large shrub or small climber bearing pale apricot flowers.
- Sun Flare – knee-high shrub bearing yellow flowers, lovely foliage.
- Playboy – head-high shrub bearing yellow & red single flowers.
- Mary Rose – waist-high shrub bearing rosy pink old style roses with fragrance.
- Eglantyne – waist-high shrub bearing pale pink old style roses with fragrance.
- Graham Thomas – head-high shrub bearing yellow old style roses with fragrance.
- Sophy’s Rose – waist-high shrub bearing raspberry red old style roses with fragrance. It’s practically bullet-proof.
- Lady of Megginch – waist-high shrub bearing raspberry red old style roses with fragrance.
- Sea Foam – thigh-high groundcover rose bearing white flowers against glossy green foliage.
- Nicole – shrub bearing white flowers with pink margins.
- Julia Child – tough shrub knee-high bearing fragrant yellow flowers. Recommended.
- Rainbow Sorbet – vigorous waist-high shrub bearing pink, white, and yellow flowers all season long. Highly recommended.
- Pink Parfait – tough, low growing rose with pink flowers.
- Zephirine Drouhin – climbing rose tolerant of shade bearing pink flowers.
- Champlain – shrub rose with red flowers.
- John Davis – climbing rose withpink flowers.
- Henry Kelsey– climbing rose with reddish flowers.
- Electron – hybrid tea rose in electric pink that is pretty tough.
- Midas Touch – hybrid tea rose with bright yellow flowers that is pretty tough.
- Olympiad – hybrid tea rose with bright red flowers that is pretty tough.
- Europeana – vigorous knee-high rose cranks out dark red flowers all season.
- Duftzauber 84 – big, vigorous hybrid tea rose makes fragrant red flowers.
- Queen of Denmark – shrubby rose with grayish foliage makes neat, fragrant pink roses once per year. A very formal and restrained look.
- New Dawn – climbing rose makes high-centered pale pink flowers with slight fragrance.
- City of York – once-blooming climber with lovely glossy foliage covers itself in white flowers.
- Cupcake – pink miniature rose cranks out neat little flowers all season long.
- Gourmet Popcorn – white miniature rose
- Marie Pavie – white polyantha makes lots of white flowers when weather is neither too hot or cool.
- Verdun – rosy pink or crimson polyantha makes lots of flowers when weather is neither too hot or cool.
- China Doll – pale pink polyantha.
That’s a list that just barely barely touches on the roses that are of easy care over most of the nation. Most of these roses will grow pretty well where Knock Out roses do: USDA zones 4, 5, 6, and 7. Some will survive in cooler zones. Many will do well enough in warmer ones, especially if given a little PM shade. They are all vigorous and fairly resistant to blackspot, at least in zone 6b, New Jersey. In zones 8 and 9 in the US southeast most of these roses are worth a try too; but blackspot is such a menace that some of these roses will suffer from the disease there. Of course, many of these roses are grown widely west of the Mississippi river, too. Some may need a little more attention when it comes to keeping the soil moist and where mildew is a problem.
The punch that Knock Out might deliver to the Eastern garden is far bigger than the rose itself. Try it. Move beyond it. Enjoy a new world of rose gardening.