The change of seasons brings a new aspect to our gardens, and autumn in central Pennsylvania can be spectacular. Some of the best fall foliage and floral displays can be found in the H.O. Smith Botanic Gardens in The Arboretum at Penn State.
Although October often brings to mind the reds and oranges of autumn foliage, there are plenty of plants that contribute colorful blooms to our fall displays. The aromatic aster (Symphyotrichum oblongifolium) is one of the more striking of our late-blooming perennials. An unassuming plant for much of the year, aromatic aster bursts forth with masses of lavender daisy-like flowers in mid-September, creating the impression of billowing purple clouds in the garden. This aster is native throughout Pennsylvania and much of the eastern and central United States, and is frequently visited by pollinating insects, including many species of bees, butterflies and moths. At a height of just 1-2 feet, the plant is much shorter than many of our other native asters, making it easy to incorporate into the garden. Aromatic aster is in peak bloom right now in our Childhood’s Gate Children’s Garden and will continue its show throughout October.
For those familiar with katsura tree, (Cercidiphyllum japonicum), fall may bring to mind the aroma of cotton candy. As this tree’s leaves turn shades of yellow and apricot in mid-autumn, they release an aromatic compound called maltol, which is the same molecule released when sugar is burnt in the process of making caramel. Although the katsura tree is native to China and Japan, it is well suited to our regional climate, and its tolerance for a wide range of soil types and moisture levels adds to its usefulness in the garden. The arboretum’s katsura tree specimen is located in our Strolling Garden — and those who visit this month may actually smell it before they see it.
Pumpkins and gourds are the centerpiece of the arboretum’s fall garden display and are also at the heart of our annual Pumpkin Festival. All of the colorful fruits on show in the botanic gardens are representatives of just four species of plants in the squash family — the field pumpkin (Cucurbita pepo), the winter squash (Cucurbita maxima and Cucurbita moschata) and the cushaw (Cucurbita argyrosperma). All of these species originated in the New World, with native ranges extending in some cases from the southern United States to the southernmost tip of South America. Pumpkins and squash also have the distinction of being some of the oldest crops cultivated by humans — at one ancient settlement site in Mexico, there is evidence that people were growing field pumpkins as a food source 8,000 years ago.
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Everyone is invited to celebrate fall with us at the upcoming Pumpkin Festival. Beginning at 1 p.m. on Sunday, people may pick up a free pumpkin to carve for our annual jack-o’-lantern contest. On Friday, Oct. 14 and Saturday, Oct. 15, the festival will feature food, music, family activities and, of course, a lit display of hundreds of carved pumpkins.
OLLI at Penn State — open to adults who love to learn — is offering more than 120 courses this semester. Shari Edelson will lead tours on “Autumn Interest at The Arboretum at Penn State.” For more information, call OLLI at Penn State at 867-4278 or visit olli.psu.edu.
Shari Edelson is the director of horticulture and curator of The Arboretum at Penn State.