My wife had two rose bushes that contracted some sort of disease a couple of years ago and despite treating them, it eventually killed them. I pulled them out and have let them dry over the last 2 years. I got them out today and realized that the base just above the roots was actually a burl. I did not notice it when I pulled them up because the disease caused hundreds of very small, fine thorns to grow and I avoided that end completely.
When I pulled them out this afternoon the thorns had all fallen off and I got my first good look at the base. I was very surprised to find the burl and couldn’t wait to see what it looked like. I was not disappointed.