The Fitolacca of the Capitoline

Rome's most improbable street tree is originally from the Argentine pampas, and it owes its spot on the Capitoline Hill to a 50th birthday party. Prince Baldassarre Ladislao Odescalchi planted it in 1911, the year Italy marked half a century since unification, at the foot of Michelangelo's Cordonata staircase beside the church of Santa Maria in Aracoeli. It is a Phytolacca dioica, called ombu in its native South America, a fast-growing evergreen with a swollen, buttressed trunk that looks more sculpted than grown. At roughly 115 years old it is the youngest tree on this list by a wide margin, but nothing else on the Capitoline canopy touches its scale: its crown now shades a stretch of the climb toward Piazza del Campidoglio, competing for attention with the ancient temple platform the hill was named for. Tourists photograph the she-wolf statue and the Michelangelo-designed piazza above; the tree that actually shades their walk up rarely gets a caption. It is one of Rome's officially registered monumental trees despite being, in local terms, barely out of its youth.