Don't you just love seeing nature take structures over? My imagination presses fast-forward and vines envelop churches and buildings and trees grow out of tall walls. The fact that nature doesn't give a hoot whether something is man-made or not, just makes me laugh. A stone wall is just a straight piece of rock ready to be conquered. You can't stop the impulse.
The cemetery is a good place to observe this. People can't keep up with all the seeds falling in all the crevices. This makes it a good place to collect seedlings, which will otherwise be chucked.