MRS FAQs Post: March 23, 2005

Cal Birtic, March 23, 2005 I am planning on adding a rose called Blanc Double de Coubert to my garden. I would to know how quickly they grow to their mature size, and how fragrent are the flowers? Is there a organic spray I could use to keep the jap. beetles away? Thanks cal

3/23/05 Cal, Blanc Double de Coubert's growth rate will depend on growing variables such as the amount of sunshine per day, available nutrients, etc. As for any shrub give it three years to mature. The flowers are fragrant and do attract beetles. You can mostly likely spray K-Neem oil on the beetles for a contact kill but this will not prevent them. Check it out on one or two flowers to see the reaction of the plant before spraying the entire plant. Jerry Cinnamon MRS Member

3/23/05 Hello Cal, First of all, Blanc Double de Coubert is a wonderful hybrid rugosa rose that will grow at the same rate as other roses in your garden, it will depend on the size and age of the rose when you plant it, and the conditions you provide it to grow in. The zone you are growing it in will factor into this also. This rose has a beautiful fragrance, and is a healthy disease resistant plant as are most rugosas. Because Blanc is a rugosa, you will not want to spray it with anything, on the whole, rugosas detest being sprayed. I am not sure there is anything you can spray them with for Japanese Beetles without causing another problem. I nearly killed my Hansa rose by spraying it. Hopefully the spray they have used to control JBs will really be working this year, and we will see a great decline in the numbers of the hungry little devils. Look for a white spot on the back of the beetles, do not kill these beetles, they are infected with the "cure" and will spread it to other beetles. We had alot less beetles in our area last year, and I am hoping it was caused by this new cure. In the meantime, daily patroling your roses and knocking them off the plant into a jar or can of soapy water is your best bet. I flush these guys down the toilet, pouring them onto the ground could allow eggs to enter the soil, so I have been told. So, to be sure I flush them. It won't hurt your sewer or septic. Good luck, I am sure you will love your Blanc Double de Coubert rose, the flower is beautiful, the fragrance is beautiful, and so is the bush! Joan Joan Gotlibson MRS Member

3/23/05 Dear Cal: I am a California antigue rose grower who has grown Blanc de Double de Coubert. It is a wonderful hybrid rugosa with an intoxicating scent. Blanc has a low growth habit even in Zone 9. You can expect full growth in 3 years. Try a mixture of baking soda and ivory soap. The beetles breathing tubes will clog and then they die. Good luck. Gary A. O'Neil MRS Member