Guest author: Katrien de Waard, 2025-2026 Public Horticulture Intern
Congratulations on surviving the longest day of the year! In honor of the summer solstice, I wanted to highlight some beautiful blooms, and in honor of sweating unstoppably in the gardens for the rest of the week, I wanted to highlight some shady spots to appreciate our marvelous solar system’s life-granting star and all her splendor from a shady distance.
Rudbeckia hirta – black-eyed Susan
What screams sunshine more than the lovely inflorescences of the family Asteraceae, home of the sunflowers. And flooding our meadows right now are the sunny yellow smiles of the black-eyed Susan, Rudbeckia hirta. These sun-loving, drought-tolerant, prairie plants are the perfect wink-and-nod to the sun as it keeps you up from 6 A.M. to 9 P.M.
Too much sun? Not enough rain? No such thing for R. hirta! These flowers do best in drier summers as their bristly hairs tend to hold water and collect diseases. These native plants will grow up to three feet tall and hold their blooms through the rest of the season. If you’re looking to grow your own, opt for slightly acidic, well-drained soils. These plants will readily self-seed each yearl, returning brightly to your garden for years to come.
They’ve truly blossomed by the Dining and Community Commons. Join the bumblebees and the Gorgone checkerspot butterflies as they flit amongst the flowers this week, and take a breather on the bench under the magnolia tree.
Catalpa bignonioides – southern catalpa
Perhaps the only snowfall you’ll be getting in Pennsylvania this time of year is from the delicate flower petals of the southern catalpa (Catalpa bignonioides). Out in bloom behind Mertz Hall, the catalpa’s bell-shaped flowers sing with their soft white petals, careful strokes of purple, and twinkling speckles of orange. In the coming weeks, keep an eye out for their incredible, foot-long seed pods that will no-doubt coat the lawn as well.
These soaring trees with their buttressing branches, create a perfect outdoor room for the sweaty passerby. Our southern catalpas reach 37 feet, with the average C. bignonioides height sitting around 25-40 feet, and its massive heart-shaped leaves create quite the umbrella as well. These trees are perfectly content in the Pennsylvania climate, doing best in zones 5-9 where they can occupy the breadth of the sunny summer canopy. Tucked in the shade are a collection of stumpy seats to enjoy the blooms and escape the oppressive heat.
Betula nigra [Heritage®] ‘Cully’– river birch
I’d be remiss if I didn’t give a range of sun-tolerant options. Whether drenched in summer sweat amidst the black-eyed Susans or cautiously cooling beneath the catalpas, the sun dances across sunscreened skin. For a true break – a deep shaded moment of respite – I offer the river birch grove. Amongst these trees teetering almost 60 feet, you’ll finally be swamped in some delicious, murky shade. River birch ghosts may recall being used for furniture, ox yokes, and wooden shoes, but these trees now need only provide canopy and aesthetics – perfect for a sunny, summer afternoon!
River birch perch on the edge of their zone range here in Pennsylvania, doing best in deep, loamy, well-drained wet soils, but they tolerate drought once established. As with many birches, these river birches grow fast and tall in full-sun environments, soaring as tall as 80 feet in ideal conditions. This particular cultivar is disease resistant, having a particularly excellent resistance to bronze birch borer. However, the most captivating element of these trees is their sunrise-pink, peeling bark. Visitors can thank previous Scott Arboretum interns for this generous gift: The Scott Arboretum & Gardens planted these river birches in 1997 to commemorate 20 years of education through internships, and the trees are dedicated to and made possible by the Scott interns’ donations. When you find this sweet grove nestled by the train tracks, take a moment to drink water and reapply sunscreen before adventuring onward!