By  July 14, 2020 - 9:12am
From left to right: Bee balm, or wild bergamot (Monarda fistulosa) from above; Square stems of bee balm; Bee balm in the Shawnee Hills Meadow; Bumblebee feeding on bee balm

The Arboretum is now open and despite the heat, it is a beautiful time of year to take in the sights and sounds of the Walk Across Kentucky. You’ll find many blooming plants aflutter with insects and birds. In this installment of the Curator’s Choice, I want to highlight three plants - one wildflower, one shrub, and one tree - that you will see blooming at The Arboretum in the month of July.

Our meadows are full of wildflowers and one of my favorites is bee balm (Monarda fistulosa) or wild bergamot. This summer bloomer is in the mint family, the Lamiacaeae, along with some recognizable culinary herbs like lavender, basil, rosemary, and sage. Plants in the mint family have leaves that are opposite each other and often have square stems (pictured), and aromatic plant parts. Bee balm has grey-green leaves and pale to bright lavender flowers with fringed, tubular petals (pictured). They spread readily via seed and underground stems called rhizomes. This plant is found across Kentucky, often in the margins of woodlands and in prairies and barrens. They are tolerant of many different soils and would be a nice addition to a sunny garden that gives them a little room to spread out. The leaves of bee balm can be used to make a nice tea and this plant has been used medicinally to treat stomach pains.

An example of a shrub that blooms in the summertime is the water-loving buttonbush (Cephalanthus occidentalis). Buttonbush is in the Madder family, the Rubiaceae, which is also home to the trees and shrubs that produce something very important to me, coffee beans (Coffea sp.). Buttonbush usually grow between 3 – 9 ft. tall and have opposite, elliptical leaves that are poisonous to livestock. The flowers are tubular but borne in spherical heads (pictured). Butterflies find the nectar especially attractive and various birds and waterfowl eat the fruit. These plants are found in shallow ponds and wetlands across Kentucky and would do well in a rain garden or wet, naturalized planting area. In the Arboretum, our buttonbush shrubs are concentrated in the Mississippi Embayment Wetlands and the Shawnee Hills Floodplain Forest.

buttonbush and sourwood

From left to right: Spherical clusters of buttonbush (Cephalanthus occidentalis) flowers; Buttonbush in Shawnee Hills; Sourwood (Oxydendrum arboreum) flowers; Sourwood leaves


Many of our temperate trees are spring-bloomers; think maples, oaks, deciduous magnolias, and pawpaw. There are, however, some trees that bloom in late spring and into summer, like sourwood (Oxydendrum arboreum). This tree is in the heath family, the Ericaceae, along with mountain laurels, rhododendrons, and blueberries. It is most commonly found in the Appalachian Plateau, the Knobs, and the Pennyrile. Sourwood trees are characterized by drooping clusters of white, bell-shaped flowers (pictured). The flowers are similar to many plants in the heath family, and also resemble the flowers of lily-of-the-valley. They have long, green-yellow elliptical and finely toothed leaves (pictured) and deeply furrowed bark.

Last year we collected and grew seed from sourwood trees in Berea Forest and the Arboretum and now have over 40 seedlings growing in our greenhouses. These trees will be grown and planted along the Walk Across Kentucky and shared with other non-profits for tree planting efforts. This is a tree that may be a little harder to find in nurseries and will need extra care in your garden, such as adding soil amendments to help lower the pH.  Although it may be a little extra work, it would be a striking and unique specimen planting.

Keep your eyes peeled for these special plants when you are walking around the Walk Across Kentucky and if you need help finding them, visit Arboretum Explorer. And don’t forget to bring a mask and social distance!

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