Astilbe in the Chelsea Grasslands in JuneTom Smarr, head of horticulture for Friends of the High Line, in the Interim Walkway in August 2013 holding Staghorn sumac (right hand) and Ailanthus altissimo (left). Ailanthus was always present all over the wild High Line, but sumac was found only in this one place near 34th streetAllium stipitatum, ‘Mt. Everest,’ in the Chelsea Grasslands