Get outdoors this holiday season and visit the National Arboretum! With 451 acres of gardens, collections, and green space to explore, it’s the perfect place to enjoy nature in the heart of D.C. The National Arboretum is open every day from 8 AM to 5 PM, except on December 25th. The National Bonsai & Penjing Museum is open every day from 10 AM to 4 PM, but is closed on all federal holidays from November through February and on Memorial Day. Admission and parking at the Arboretum are free.