The Judas Tree of the Altes AKH

This tree flowers straight out of its own trunk. In spring, before a single leaf opens, Cercis siliquastrum covers itself in rosy-pink flowers barely two centimetres across, and they push out not only from the twigs but from the branches and the old wood of the trunk itself. It is a habit called cauliflory, common in the tropics and close to unknown on a street in central Europe. Its age is a genuine argument. Vienna protected it on 14 February 1995 on the grounds that it was already well over a hundred years old, which puts a hard floor of roughly 130 years under it today. Local reporting adds that it was probably planted in the eighteenth century, along with the institute buildings around it, which would make it closer to 240. Nothing settles that, so the range stays wide. Even its monument number is disputed: most sources call it Nr. 762, while the city's own 2025 press release calls it Nr. 769. The courtyard was part of one of the most modern hospitals in the world when Joseph II opened the Allgemeines Krankenhaus in 1784, on ground that had held a poorhouse since 1693. The hospital moved out and the University of Vienna took the buildings in 1998, so the second courtyard now has cafe tables around it. The tree grows as ten old stems with young shoots between them, renewing itself indefinitely as long as nobody tidies it up.