Question
QUESTION: Morning Jay, I have a problem with powdery mildew on a couple of new roses. I'm after advice on how to control this please. Do I need to cut back all affected canes (which will make the plant look very bare!!!) or can the leaves stay on?

I have some neem oil, and also some wettable sulphur I'm keen to use if appropriate. The two bushes that have mildew also had blackspot when they were bought, however that was very confined to a few leaves which i removed....all new growth black spot free so far.

Can i use the two products at the same time, or is one a cure all for black spot and mildew.

Thanks in advance

Mark (south coast of UK)

ANSWER: Hi Mark,

Use the copper to go ahead and get rid of the powdery mildew.  You do not have to cut back the canes or the leaves.  

I would not use the oil and copper together.  Once you have disease under control, then the neen oil will help to prevent the black spot and mildew.  Please watch your daytime temperature as here in the States, it is not recommended if it is over 85 degrees.  

Hope that helps,

Please feel free to ask more questions if you need to .

Jay

---------- FOLLOW-UP ----------

QUESTION: p.s. 85 degrees!!!! this is the south of England, haha! in final answer to your question, i top dressed with composted manure and a handful of bonemeal around each plant in jan/feb. I wasn't planning on fertilising until after the first flush of flowers (Vitax Q4)...is this correct??

Answer
HI Mark,

This summer is going to be brutal everywhere I believe.

Typically, you can fertilize your roses once your danger of frost has passed.  This way they have some food to really bloom in the spring.   I do not recommend fertilizing them if they are newly planted.

Hope that helps,

Jay