Make sure it is in enough sun and cut it back hard. Spiraeas can be cut back to the ground with no ill effect and the foliage should come back relatively clean.

Rust is a very difficult plant disease to control and one method to discourage its development is to improve air circulation. Cutting back hard is one of the best methods to accomplish this. Also, the humidity of NC may not be at all to its liking which could be encouraging the disease as well. As with most fungal diseases, you need to be proactive and spray for prevention (cuz you can't cure!)

Or if the process is just too much effort, rip it out and try something else less problematic :-))

Thanks gardengal48. This bush has sun from sun up to sun down. We are in the mountains so humidity is not that bad. The plant after two good years and two bad years is not very dense, so fungus from density shouldn't be the problem. This was an old tobacco field and I have heard that the plantings over the years has leached the soil of nutrients although everyone says a bridal wreath doesn't need much fertilizer. Also, could a cedar within 40 feet cause the rust. This plant is also on a knoll that has good drainage....so in my mind everything is perfect for the plant ....but it is miserable.

on what basis are you diagnosing rust??? ... color alone???

cut it to the ground.. it can take it ... this is one sure way to get rid of a lot of topical diseases ..

is it near a fertilized lawn??? could it be getting too much nitro.. favoring green growth over flowers ...

is it sprayed by lawn sprinklers???

these are extremely easy to grown.. cant kill them by running them over with a truck ... and should be near disease free ... i dont understand this situation... especially without a pic ... or reassurance of the ID ...

and i would not trust the ID of the guy who sold you the spray .. unless it was from a professional nurseryman .. as compared to a hardware guy ..

ken

rust not seen on spirea:>

http://forums2.gardenweb.com/forums/load/shrubs/msg0506573815714.html?3

Here is a link that might be useful: rust is not listed as a problem