I succumbed to the lure of growing my own rhubarb, and bought a young plant in August. I planted it in our tiny front garden(about 3 yards square), and it loves it there! It's about 18" from one of the corners. On the opposite wall to the rhubarb corner we have a young grape vine and a climbing rose. It seems that there is quite a lot of bare soil. I've read that rhubarb needs its own space, but how much space?
Ideally about 3 feet all round the plant, but don't worry too much if it has less! It also needs a sunny spot and soil that doesn't get water-logged in winter.
If it's well fed, as it ought to be, it'll grow to the point where it will eventually smother everything within about three feet. So give it that much and you know you won't have any problems later.