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Coral Knock Out® Rose

Rosa 'Radral'

Close-up of Coral Knock Out® flowers at sunset in May 2020. Photo J Sisneroz.
Close-up of Coral Knock Out® flowers at sunset in May 2020. Photo J Sisneroz.

Summary

Coral Knock Out® is a medium-sized shrub rose with generally uniform habit. In both Davis and Irvine, the foliage on this rose was unacceptable in appearance and health from spring through fall, unlike other roses we have evaluated in the Knock Out® series. It was affected by both black spot and thrips damage yielding plants without good leaf coverage. In Davis, leaves on some plants wilted frequently on all irrigation treatments during the hottest part of the summer. Coral Knock Out® put on a nice flush of bright coral-orange blooms in April and May in Irvine. The first bloom was more modest in Davis and dead brown petals hung on the plant rather long before self-cleaning, giving the plants a messy appearance much of the season. In both locations, many plants had significant leaf loss by September due to the combined stresses of disease, heat, and in Irvine, reclaimed water. Because of the serious foliage issues, we would not recommend Coral Knock Out in either the hot inland valley or coastal regions of California.

Basic Info

Submitted by: Star Roses & Plants
Trial Exposure: Sun
Year evaluated: 2020
Height & Width
(after 2 years):
 32" x 53" - UC Davis
 35" x 55" - SCREC
Reported Height & Width
(at maturity):
54" x 54" 
WUCOLS plant type: S
Water Needs & WUCOLS Region:
 NA- Region 2 
 NA- Region 3
Mean Overall 
Appearance rating:
(1-5 Scale, 5 is highest)
 NR - UC Davis 
 NR - SCREC
Flowering Months

 April-Oct. - UC Davis

 April-Oct. - SCREC

Growth and Quality Data

Click Here for Complete Data Set

Close-up of Coral Knock Out® flowers at different stages of senescence in October 2020. Photo J Sisneroz
Close-up of Coral Knock Out® flowers at different stages of senescence in October 2020. Photo J Sisneroz

Rosa 'Radral' Coral Knock Out® on low water at UC Davis in May 2020. Photo: K. Reid
Rosa 'Radral' Coral Knock Out® on low water at UC Davis in May 2020. Photo: K. Reid

Rosa 'Radral' Coral Knock Out® on medium water at South Coast REC in August 2020. Photo: D Martinez
Rosa 'Radral' Coral Knock Out® on medium water at South Coast REC in August 2020. Photo: D Martinez