The Olive Family (Oleaceae) at The Morton Arboretum includes more than 20 genera. The collection was started in 1923 and contains the oldest living accessioned plant in the Arboretum collections, swamp-privet (Forestiera acuminata).
Ash (Fraxinus) trees are noted for their use as hardwood timber and can be found in woodlands as well as in urban landscapes. There are twenty-eight different kinds of ash trees in this collection. Forsythia (Forsythia) is a valuable landscape shrub. Its vibrant yellow flowers bloom in early spring before leafing out. Look for Meadowlark forsythia (Forsythia 'Meadowlark'). This is the hardiest hybrid, a combination of early forsythia (F. ovata) and Albanian forsythia (F. europaea). Fringe tree (Chionanthus) is a small tree or large shrub genus that is represented in this collection by both native fringe tree (C. virginicus) and Chinese fringe tree (C. retusus). It gets its name from the long, fringy, and creamy-white aromatic flowers it produces. In the fall it forms a dark blue rounded fruit.
Lilacs (Syringa), known for their scented spring flowers, vary in size from large shrubs to small trees. One of the tree lilacs in this collection is Beijing Gold Peking lilac (Syringa pekinensis 'Zhang Zhiming'). This is a relatively new introduction by the Arboretum through the Chicagoland Grows® Plant Introduction Program. It produces beautiful light yellow flowers and attractively peeling bark. A related cultivar, Morton Peking lilac-China Snow® (S. pekinensis 'Morton') is another Arboretum introduction, selected for its graceful upright-rounded habit, fragrant white flowers in mid to late June, and cinnamon colored exfoliating bark.