Anyone ever heard of a spontaneous rose bush growing?

[Curmudgeoness]

4. Many cultivated roses are grown on rootstock

of roses that are not desirable. If the sucker is from one of these rootstocks, you would not get something that you would want. See this link for an explanation:

http://www.heirloomroses.com/care/rootstock/

But with that said, I have a rose bush that was grown from a cutting, and it also has other roses growing up around it. They will all be the same rose, since there is no rootstock that was used.

As to a rose bush in a different part of the yard, I cannot explain that. I have never heard of it, but have a feeling that the bush would not be very tame. There are some roses (at least in my area in Pa) that are invasive (multi-flora rose), and they are not something that you want growing....they spread like crazy.