Question
Gil, my 2 year old butterfly bush has rust colored spots on it and also some of these leaves are curling up.  We are having a cool wet spring this year so my sprays haven't been effective.  Can you tell me what this is and what to use?  Thank you   Carol

Answer
Hello Carol

This sounds like a case of fungal leaf spot, which can occur when there has been a prolonged period of wet weather early in the year.  Leaf spot is disfiguring, but not fatal to the plant.

The best thing to do is pick off as many affected leaves as possible and bag and bin them.  In the fall rake up all the fallen leaves to minimize the possibility of the infection being carried over to the following year.  

If you have to water the plant it is best to water at the roots rather than overhead (with a spray attachment to a hose, for example) as this can wash spores down onto unaffected leaves.  Also, don't be tempted to fertilize your plants as it will encourage a flush of fresh new leaves which will be more susceptible to leaf spot.

There are chemical and non-chemical fungicidal sprays available from the garden center and rather than me advising you which to use, I think it would be better to get some on-site advice -always read the instructions on the packaging carefully.

If you do decide to use a fungicidal spray, use it as early in the growing season as possible - when the buds have formed, but not yet opened is ideal.

Gill