well first off who owned the house before you? and before that and is anyone still living? Probably a grandchild ect could tell you 'yes, I remember when grandma planted that' that will give you an age moreso. But chances are if the neighbor told you that it is probably true. How old is the house? that time era will give you an idea of the roses popular and available for the day. If it is 50 years old, there is a good chance it isn't grafted, and is on it's own roots (like 100% chance most likely) which is good. Lets face it, if it is 50 years old this has seen a lot of neglect, so caring for it minimally is probably best, supposing it is doing ok on it's own. It's healthy right? I mean it's blooming so it must be happy. All you need to worry about is doing anything inadvertently to harm it. Like accidentally weed eating, which would probably grow back, accidentally spraying w over drift of herbicide, or allowing a dog to pee on it regularly, or things like that. toss a little rotted cow manure on it and some mulch and it will love you! also, full sun, so don't plant or erect anything near it that will block the sun too much, roses are sun lovers.
