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Cutleaf coneflower (Rudbeckia laciniata)

What's in Bloom: August

Welcome to the Morris Arboretum’s first What’s in Bloom blog! As this year’s John J. Willaman & Martha Haas Valentine Curatorial Intern, I spend a lot of time in the gardens checking on and appreciating the many plants in our living collection throughout the seasons. We want to share some of these with all of you, so we’ve curated a monthly blog that highlights current flowering plants and seasonal interest so you can know what to expect and what to look for during your next visit to the Arboretum. We hope this series complements the stunning, expansive views of the Arboretum and encourages you to find the beauty that comes from taking a closer look.

Surprise lily (Lycoris squamigera)

You’ll find this lovely late summer bloom dotted throughout the Arboretum, providing some welcome color in the gardens. Native to southern Japan, surprise lilies produce foliage in late spring that dies back in early summer before suddenly sending out a single flowering stalk in August—hence the surprise! You will see lots of these lilies along the paved path towards Out on a Limb, where clusters of pink under the shade of great trees lead you into the beauty of the Arboretum in late summer. 

Hollow Joe-Pye weed (Eutrochium fistulosum)

It’s pollinator season here at the Arboretum, and our butterflies, moths, and bees are swarming around these tall, colorful native plants throughout our gardens. There’s an established cluster of Joe-Pye weed at the Swan Pond, whose seven-foot-tall stalks are topped with clouds of pink flowers. I’d recommend taking a moment to observe all of the beautiful pollinators that flock to these flowers, such as monarch and eastern tiger swallowtail butterflies.

Diana rose-of-Sharon (Hibiscus syriacus ‘Diana’)

Perhaps one of the first bold blooms you’ll encounter at the Arboretum, this rose-of-Sharon variety produces showy white flowers and is located just by the Widener Visitor Center. This cultivated variety (cultivar for short) is named after the Roman goddess Diana (Artemis in Greek mythology), the goddess of the hunt and the moon. These beautiful Diana rose-of-Sharon shrubs will continue to bloom until the fall.

Shoal Creek chastetree (Vitex agnus-castus ‘Shoal Creek’)

These fabulous shrubs are blooming in the Rose Garden and, like the Joe-Pye weed, are attracting lots of pollinators. Nestled in between rose bushes, these purple-blooming chastetrees add color and fragrance to the Arboretum while most of the roses have already finished blooming.

Cutleaf coneflower (Rudbeckia laciniata)

When you enter the Arboretum through our main iron gates, look to your left: you’ll notice a field of bright yellow flowers welcoming you in. These native coneflowers are one of many plants in the meadows of our Natural Lands section. In 2006, the Arboretum began a revitalization of our natural areas, which included creating meadows with diverse plant life to provide habitat for insects and wildlife. Not only is cutleaf coneflower a beautiful summer bloom, it is also a valuable pollinator plant that supports our wildlife year after year.

Blue Boa giant hyssop (Agastache ‘Blue Boa’)

These tall clusters of giant hyssops are thriving in our newly-planted beds at the Step Fountain, attracting a wide variety of pollinating insects and even the occasional hummingbird. Agastache is native to North America, and the Blue Boa cultivar offers bold and attractive color in this redesigned garden area with its bright blue/violet flowers contrasted against its deep green foliage.

BOBO panicle hydrangea (Hydrangea paniculata ‘Ilvobo’)

Although most of our hydrangeas are phasing out of their bloom, the BOBO panicle hydrangeas in the Rose Garden are now in full bloom, with beautiful white flower clusters glowing in the full sun. These hydrangea cultivars are bred to remain compact in size, reaching only about three feet in height. Compare this variety to the large straight species panicle hydrangea on the island in the Swan Pond. There, the plant has been ornamentally pruned to look more like a tree rather than a low shrub.

Pink summersweet clethra (Clethra alnifolia ‘Rosea’)

You will likely smell this plant before you see it! This established mass of clethra shrubs is in full bloom along the stream above the Swan Pond. Its many clusters of small, delicate pink flowers give off a delightful aroma. Pollinators, including hummingbirds, love visiting these flowers. Take a seat on the A-frame swing facing the Swan Pond, part of our Summer of Swings exhibition, and enjoy the fragrance of this clethra while taking in the Arboretum views.

Nora Wildberg received her bachelor’s degree in Art and Archaeology from Princeton University in 2021, focusing her studies on museology. Having previously worked with an ancient coin collection, she now works directly with the Morris Arboretum’s living collection assisting in the preservation and record-keeping of our woody plants. In recent years, she developed a passion for plants and nature, and in her free time, she enjoys birdwatching, painting, hiking, and looking at art.