Posted: 19/07/2013 at 17:34
Don't plant the new ones there, they'll get rust as well - the spores live in the soil, and infect the plant when splashed up by rain or watering.
If you have rust in your area (it likes clean, pollution-free air), you will never get rid of it, only control it. As well as spraying with a fungicide (take your pick from the garden centre - anything that says it treats rust will do), feed the plant well - you can often get the plants to grow vigorously enough so that the rust is less of a problem.
In autumn, once you've cut the plants down, mulch around them well to suppress as many spores as possible.
And no, a soap spray is no use at all - it's a fungus, not an insect problem.