jimnks wrote:Hello all, my wife planted 7 knockout roses in a bed last year, they did fine, this year they have taken off alright, but have new shoots coming out of every plant that are twice as tall as the original plant, the canes are as big around as our tea roses, and the leaves are 3 times as big, but the flowers are the same size as the ones on the original plant. Do you think they froze? What to do, cut back large canes to ground level, cut back canes to level of the rest of plant, or something else? We live about 35 miles west of Kansas City. Have a nice day!!!
The first Knock Out roses that I bought several years ago were grafted on to Dr. Huey rootstock. Interestingly, most Knock Out's that I've seen in recent years were all growing on their own roots.
However, Dr. Huey is pretty much the standard these days (in the USA) as a grafting rootstock.
If the blooms on the big canes are red
, it may be very possible that it's Dr. Huey rootstock growing. And if this is in fact the case, those canes need to be removed at the source, which is below the crown.
If left alone, this growth will eventually take over your Knock Out rose, and Dr. Huey is indeed an extremely tough and vigorous grower.