Roses have long been sentimental garden favorites but which of the hundreds to choose from are best grown here? UF researchers have just released the results of a two-year study on low maintenance shrub roses suitable for Florida. Shrub roses have gained popularity in recent years due to claims of minimal care in the landscape. The trials evaluated seven Old Garden and five Modern shrub roses (non-grafted) for use in north, central and south Florida.
The highest ranked rose for flowering in all three regions was the original Knock Out®. From a plant quality standpoint, the roses with the longest periods of acceptable to very good appearance in central Florida were ‘Mrs. R.B. Cant’ and Knock Out®, followed by ‘Spice’, ‘Bailey Red’ and ‘Duchesse de Brabant’. With the exception of the patented variety, these are Old Garden roses.
Those cultivars performing poorly in central Florida were ‘Perle d’Or’, Carefree Beauty™, ‘Old Blush’, ‘Belinda’s Dream’ and Home Run®. These are Modern roses with the exception of ‘Old Blush’. Study plants in our area suffered severe damage from chilli thrips (Scirtothrips dorsalis) as well as black spot and Cercospora leafspot diseases. In many cases these pests caused severe decline or death of the poor performers.
The researchers, Gary Knox, Sydney Park Brown and Sandra Wilson, note that ‘Mrs. R.B. Cant’ is less affected by chilli thrips than other roses probably because the new foliage on which the thrips feed is produced cyclically rather than continuously.
Extension agent Mary Beth Henry conducted a study of companion plants attractive to beneficial insects and suitable for rose gardens, with Alyssum Snow Princess™ showing good results.
UF/IFAS Extension will present a tele-conference, “IPM for Commercial Production and Use of Shrub Roses”, on July 22. Please let us know if you are interested in attending at our Manatee County office.