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Posted by Faye Green

Compared to their hybrid-tea cousins, Knock Out Roses are relatively care-free. But with a little extra care, they’ll stay even more beautiful all summer long.

Since their introduction in 1999, Knock Out® roses quickly became the most popular rose in North America. A floribunda, this thing of beauty has an ancestry that draws the best qualities from each contributor to its lineage. To get from there to here, here’s what William Radler did: He put together the hybrid tea, thepolyantha rose, and the Rosa chinensis and Rosa multiflora.

Then something miraculous happened, and behold the result. Floriferous, compact, disease resistant, easy-care repeat bloomers. There you have it—the story from a gardener, not a hybridizer.

The original red Knock Out has come a long way. You may add yellow, pink, and bi-color, even double blooms, but you still have a no-muss, no-fuss, easy-care rose, a description of roses previously considered an oxymoron.

Indeed, you can almost plant it and forget it. Please make note of that little qualifier “almost.” Let’s pursue what that word really entails—state the facts and then examine the myths of Knock Out roses:

Facts about Knock Out roses:

  • They need sun.
  • They grow 3 to 4 feet tall and wide.
  • Knock Outs bloom non-stop all season.
  • They’re compact enough for containers on decks and patios.
  • They have a 5 to 6 week bloom cycle.
  • They’re hardy to zone 5 and heat tolerant.

Now let’s deal with prevailing mythsabout Knock Outs:

1. They are self-cleaning, so they don’t need dead-heading.

Technically true, but it would be a good idea to cut spent blooms to prevent the energy of the plant going to setting hips instead of blooms.

2. They don’t need pruning.

Please prune, but with a scalpel rather than a machete. Pruning to about 12 to 18 inches in early spring is recommended to encourage stellar performance because flowers emerge from new wood. Cut to about 3 to 6 inches after especially harsh winters to cull out dieback. In addition, take the clippers to them when they lose their attractive shape.

3. They are shade tolerant.

Hmmm. . . I wouldn’t test that assertion. Roses like sun. Period.

4. They are resistant to black spot, mildew, and rust.

Resistant, yes, but probably more so if you don’t test their shade tolerance. Sun is a wonderful anodyne.

Feeding: Give your Knock Outs a good feeding in the spring with rose food, then follow that up with foliar feeding until the last time you fertilize for the season.

There! Compared to hybrid teas, the care of which is onerous and ongoing, Knock Outs are easy-care.