Syringa reticulata subsp. pekinensis Syringa reticulata subsp. pekinensis Syringa reticulata subsp. pekinensis (formerly known as "Syringa pekinensis"), also known as the Pekin lilac or the Chinese tree lilac, grows in an open, multi-stemmed form to a height of , with a spread of . They are native to northern China but grow in USDA hardiness zones 3 through 7. It is grown as an ornamental tree in Europe and North America. Pekin lilacs have arching branches and ovate dark green leaves that are long. They have yellowish-white flowers that bloom in panicles up to long. The panicles change over to loose clusters of brown
Chicago Botanic Garden by John O. Simonds and Geoffrey Rausch. Several famous buildings have been designed by well-known architects since 1976. The Chicago Botanic Garden opened the Daniel F. and Ada L. Rice Plant Conservation Science Center, located at the south end of the garden, to the public on September 23, 2009. In September 2010, the Plant Science Center earned a GOLD LEED (Leadership in Energy and Environmental Design) rating from the U.S. Green Building Council because of its sustainable design. The Chicago Botanic Garden conserves rare plant species, and is working with regional, national and international organizations on behalf of plant conservation.