by Tony Aiello
Autumn is one of the most popular times to visit the Morris Arboretum, and visitors enjoy the colorful displays of the sugar maples (Acer saccharum) along the entrance drive, the vibrant backdrop of the black tupelos (Nyssa sylvatica) above the Rose Garden, and the cathedral-like group of dawn redwoods (Metasequoia glyptostroboides) in the Sculpture Grove. Typically, around Oct. 25 is a great time to wander through the gardens to view peak color.
Wherever you might wander throughout the Arboretum, you are sure to come across an unusual tree or shrub that adds to the variety of display, and also some plants that are notable for their fall flowers and fragrance. Some of visitors’ favorite plants are actually found off the beaten path. Some of these are available commonly at garden centers, while others are true botanic gardens curiosities.
If you walk from the Widener Visitor Center towards Gates Hall, between the small parking lot and the Orange Balustrade you will find Acer palmatum ‘Heptalobum’, one of the most outstanding Japanese maples for red fall color. Continuing from there toward Gates Hall, you will see the incredible golden foliage of Princeton Gold Chinese witchhazel (Hamamelis mollis ‘Princeton Gold’).
At the bottom of the Holly Slope, tucked behind the signature katsura-tree (Cercidiphyllum japonicum), are several broad-leaved evergreens that are growing in the shade and protected from harsh winter wind. These are Camellia oleifera (tea-oil camellia), with its beautiful white flowers, and Camellia sinensis, the plant from which tea is made, with its small white flowers. Between these is an impressively large shrub, Osmanthus armatus (Chinese osmanthus), prized for its small but very fragrant flowers.
Around the corner is one of the most interesting plants for fall color, used as a hedge surrounding the Long Fountain, Lindera salicifolia (one of the Asian spicebushes and related to the native Lindera benzoin). This plant colors very late in the fall turning a variety of reds, yellows and oranges before the leaves fade to russet and persist through the winter.
As you encircle the Swan Pond, you will find a quieter interest in Hamamelis virginiana, a native common witchhazel. Common witchhazel displays a modest yellow fall color, but is most renowned for its profusion of small fragrant yellow flowers. This deer-resistant species is native throughout Pennsylvania and one can find sizable plants growing throughout the Wissahickon Valley. Downstream from the Swan Pond, along the East Brook are several plants of a native shrub, southern blackhaw viburnum (Viburnum rufidulum) with burgundy-colored leaves and bright blue fruits that are attractive to birds. Behind these stands the majestic Engler beech (Fagus engleriana) with its russet-red fall color and leaves that also persist into winter.
Surrounding the Engler beech are a number of small trees that make great additions to any landscape. These include Stewartia pseduocamellia (Japanese stewartia) a choice landscape plant with beautiful bark, white flowers in June, and rich red-orange fall color; nearby is Parrotia persica (Persian parrotia) a medium-sized tree also with beautiful bark and leaves that start out with deep purple color before turning a mix of yellows, oranges, and reds. Parrotia is a tough tree suitable for gardens, planting strips, or urban settings. Plants with yellow fall color are often overlooked, but the clearest, strongest, and most reliable yellow in the Arboretum belongs to Carpinus cordata (heartleaf hornbeam), also growing nearby.
It is always worth the extra effort to wander further through the English Park. Among staff favorite plants in this part of the Arboretum are the Okame cherries (Prunus ‘Okame’) with their red fall color and the majestic white oak (Quercus alba) with its unique purplish red color, perhaps the favorite of all.
The Morris Arboretum of the University of Pennsylvania is located at 100 East Northwestern Ave. For more information, visit www.morrisarboretum.org.
Tony Aiello is Director of Horticulture and Curator at Morris Arboretum. He is giving a class at the Arboretum on Saturday, Oct. 20, called “Great Plants for Fall Color: A Tour with the Arboretum’s Curator.” Register at online.morrisarboretum.org/classes