Nurseries often stock things which are supposed to repel possums, products with names like poss-off. You often see trees with ugly plastic skirts on supposedly to prevent possums climbing them.
I am fond of the possum in the picture. I think it is not very bright, because its nest is quite low and next to a path. I can catch a glimpse of possum fur if I stand on tip toes, as it sleeps in the daylight. Once I got up early, when it was just light and I saw it coming home along the fence from its night out. When it saw me it was quite surprised, and sidled past its nest, doubling back and jumping in when I pretended to look away.
When I see it at night it is generally alone, but I know it has mates because I hear them growling and hissing to each other. They don't eat the plants in my garden, maybe because they get a free meal from the compost heaps.
A garden without wildlife is sterile. I don't just want a few plantings, I want a rich ecosystem. I do believe that human beings have a right to live in the suburbs, and of course this will impact on non human residents. But I wish we could all struggle to find a way of sharing our environment, be prepared to comprimise and at least try to find a way to achieve peaceful co-existence.