Rose sickness is rarely described or explained properly, for in some cases it happens, and in other cases it doesn't! Until quite recently there was some scepticism as to whether Rose Sickness actually existed.
Generally, where a rose has been removed - for whatever reason - and a new one put in its place, the new rose either does not perform well - or in some cases never properly establishes and dies.
The reason is generally known as rose sickness. The cause is as a result of various fungi that grow around the roots and soil of the old rose. Both the fungus and the old rose seem to live quite happily in harmony. However, when a new rose is planted in the area, the fungus seems to 'attack' the new rose and leads to its demise. Jealousy! Who knows!
One theory - and it is just that - is that Rose sickness - or soil sickness - is as a result of a gradual build-up of the fungus around the old rose, which has been able to live quite happily as an established, vigorous plant. However, the newly planted rose is quickly overcome by the fungus before it can become established enough to fight off and live with the fungus present in the area.
Rose sickness can affect a whole bed - as has been found out by public parks managers who have decided to replace a bed with a newer variety! In many cases the new rose just do not get established.
One way to alleviate this problem - with just one or two roses - is to import new soil into the area where the old rose grew. You may need to take the old soil out to a depth of 50-60cms (2ft).
Incidentally, Rose sickness can also be a problem with other members of the rose family such as Apples, Pears and even Pyracantha.
The fact that the 'Sickness' can prevail in the area for up to 20 years does not help matters! It is suggested that planting Tagetes in the area for a year helps to overcome the effect of Rose sickness!
If this all seems to be a bit inconclusive, then that is the phenomena known as Rose Sickness!