Hello. I am not regular here, and I am also quite inexperienced when it
comes to roses. Can someone explain the following?

Two years ago I planted a rose - Mr. Lincoln. It grew normally, had
beautiful flowers, and towards the Fall it sprouted a strange looking twig
with small leaves on it. I left it alone, curious about what was
transpiring.

This Spring, the strange looking twig is covered with buds that are about to
bloom. It looks like a climbing rose.....
The rest of the rosebush is also full of buds.

Can anybody explain what happened to Mr. Lincoln? Why half of the rosebush
is climbing rose, and the other half remained just a rosebush? What exactly
IS going on?

I am glad that it grows by the fence. If it decides to be all climbing rose,
it will have something to cling to. Nevertheless, it is weird...