How to Care For the 'Knock Out' Rose in Summer
They say it's carefree, but it still needs some attention.
This story originally appeared on southernliving.com.
You’ve heard of all the hype about ‘Knock Out’ rose. “It never stops blooming.” “It never needs pruning.” “It never needs spraying.” “It’s the one rose you can plant and forget.” Are all of those things true? Well...
Compared to other roses, ‘Knock Out’ is pretty idiot-proof. It’s tough, grows in almost any well-drained soil in a sunny spot, and doesn’t need spraying for black spot fungus, the universal bane of rose lovers. But a rose you can just plant and forget? Forget about it.
For one thing, if you want to keep it blooming continuously, you need to groom it. This means clipping off the faded flowers. If you leave them, they’ll form rose hips with seeds inside and flowering will slow to a crawl. Grooming ‘Knock Out’ rose every week or so spurs new growth loaded with new rose buds.
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Second, ‘Knock Out’ may start out small and compact when you buy it, but it won’t stay that way forever. Unless it dies, it will get bigger and bigger every year. A neighbor of mine has hedge of ‘Knock Out’ rose that’s now pushing six feet tall. If this is too big for the space you have, you’ll need to prune. Fortunately, ‘Knock Out’ blooms on new growth, which means that you can prune it just about any time of year. Be sure to wear leather gloves, though, as it’s one of the most viciously thorny plants you’ll find. You can cut it down to a foot tall if you want. In response, it’ll send out lots of new growth and blooms.
Third, just because ‘Knock Out’ doesn’t need spraying for black spot doesn’t mean you don’t occasionally have to spray for other things. In hot, dry weather, tiny spider mites on the undersides of the leaves may suck out the sap, causing the leaves to look speckled or bronzed. Then you’ll need to spray with horticultural oil or insecticidal soap. Spraying the foliage with a jet of water also works, because spider mites love dry foliage and hate wet foliage.