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'RADrazz' rose Description
'Knock Out ®' rose photo
Photo courtesy of Seil
Commercially available
HMF Ratings:
98 favorite votes.  
Average rating: EXCELLENT-.  
Red blend Shrub.
Registration name: RADrazz
Exhibition name: Knock Out ®
Bred by William J. Radler (United States, 1988).
Introduced in United States by Conard-Pyle (Star Roses) in 2000.
Introduced in France by URS (Universal Rose Selection)-Meilland in 2001 as 'Knock Out'.
Shrub.   (Series: Earth Kind ™)  
Cherry-red.  Mild, spice, tea fragrance.  5 to 13 petals.  Average diameter 3.5".  Large, single to semi-double, cluster-flowered bloom form.  Continuous (perpetual) bloom throughout the season.  Decorative buds.  
Armed with thorns / prickles, bushy, compact, rounded.  Glossy, dark green foliage.  

Height: 2' to 4' (60 to 120cm).  Width: 3' to 4' (90 to 120cm).
USDA zone 4b through 9b.  Can be used for landscape.  Very hardy.  vigorous.  shade tolerant.  Disease susceptibility: very blackspot resistant., susceptible to Mildew.  Requires spring freeze protection (see glossary - Spring freeze protection) .  Can be grown in the ground or in a container (container requires winter protection).  
Australia - Patent No: AU4411P  on  5 Apr 2012
Application No: 2003/061  on  28 Mar 2003   VIEW PBR PATENT
Frybright x’ ‘Bucbi’ in 1993.... Breeder: William J Radler, Greenfield, USA.
Canada - Patent No: 0993  on  7 Jul 2001
Application No: 99-1678  on  25 May 1999
Breeder: William J. Radler, Greenfield, United States of America
'Radrazz' originated from the cross between a seedling of the variety 'Carefree Beauty' and a 'Razzle Dazzle' seedling.
United States - Patent No: PP 11,836  on  10 Apr 2001   VIEW USPTO PATENT
Application No: US1999000229323  on  13 Jan 1999
Shrub rose plant named `Radrazz'.
William J. Radler, Greenfield, Wisconsin
... a landscape shrub rose... single blossoms that are red... Excellent disease resistance to blackspot is exhibited...
The female parent (i.e., the seed parent) was a seedling of the `Carefree Beauty` variety (U.S. Plant Pat. No. 4,225). The male parent (i.e., the pollen parent) of the new variety was a seedling of the `Razzle Dazzle` variety (U.S. Plant Pat. No. 3,995)... The blooming cycle is believed to be one of the longest observed to date for a rose plant...
In his garden in Tyler, Texas, Mark Chamblee, of Chamblee's Rose Nursery, grows 'Belinda's Dream', 'Marie Daly', 'Marie Pavie', 'Livin' Easy', 'Easy Going', 'Knock Out ®', and 'Mermaid'. Mark likes these varieties because "they have great hardiness and disease resistance, they are low maintenance and are very free blooming."

Parentage is per the breeder. Australian patent lists ancestors (Razzle Dazzle x Carefree Beauty) in simplified form
Different ploidy stated by 2023 reference.