For those working with R. rugosa in breeding

An announcement from the Ag Dept: R. rugosa has been recently identified as a potential host to Phytophtora ramorens, aka the Sudden Oak Death pathogen. Brace yourselves for the sudden disappearance of Rugosas and their hybrids from nurseries across the country. You may want to reconsider including this species in your breeding plans. I know I’m going to think twice before using it now.



Other rose species show susceptibility to P. ramorum when artificially infected: R. californica, R. sempervirens, R. canina. R. gymnocarpa was identified as a host before. Since species are from different groups (cinnamomeae, synstylae, gymnocarpae, caninae) I wonder if the identified host plants are just the tip of the iceberg? I wouldn’t be surprised if the genus Rosa as a whole is a host plant of P. ramorum (maybe with levels of resistance varying between species).



It is not unreasonable to suspect as much, but we should all hope its not going to be the case.


It is from the very beginnings.

As soon as P. ramorum Sudden Oak Death was known genus rosa was put in the list of forbiden imports from contaminated countries.

Pierre Rutten