Philadelphus

I have black deposits hugging the buds and on some of the leaves,could someone tell me what blackfly looks like,I have to admit at never seeing it..and what should I do to cure it,I have used soapy water.and it has helped a little...........it does'nt look like a fly..I really am showing my ignorance now...any help appreciated...Suzy

 

It sounds as if you've got aphids [known as greenfly or blackfly according to colour]:
http://homepage.ntlworld.com/alan.cann/articles/aphids.html
If you have a lot, then try blasting with a hose pipe to remove as many as you can, then the soapy spray will keep them at bay.

 

Many thanks Liz,that is exactly what they look like..some of the leaves are showing a few spots of black should I remove them.?...........this is the first year of flowering..hope I dont lose it .....

 

Lets get the frogs bred asap!! Nice cite that Liz