Outside of the Transportation Center. Along Sheridan Road. Leading up to the Rebecca Crown Center. In large, showy clusters throughout Shakespeare Garden. Northwestern's staple summer bloom, hydrangeas have been planted for as long as Stephen Camburn, a groundskeeper at Northwestern University for more than 35 years, can remember.
The shrubs flower each summer quarter, covering the campus in "snowball" puffs of creamy white. Camburn said they return year after year despite environments such as polar vortices, excessive rain and drought, weather conditions he's seen affect the other plants.
Hydrangea is the genus for more than 70 individual species of flowering plants. Sarah White, Northwestern campus planner, said the landscaping team tends to opt for the puffy Annabelle hydrangeas. The Annabelle grows off new wood, meaning the flower buds develop on current year stems that grow during spring and summer.
The Annabelle also doesn't require "deadheading," or the pruning of faded flowers from plants to keep up appearance. Instead, they dry out and remain neat, flower heads shrinking but remaining on the stem. Groundskeepers cut the new growth blooms down to the ground in the late winter. When the summer sun appears and most students leave campus, the snowball blooms show off.
The hydrangea macrophylla, a variety of the shrub that blooms from old growth, is historically not very hardy here, White said. Unlike the Annabelle buds, which are not present in the winter, macrophylla buds set on last year's stems in late summer or early fall, and remain throughout the winter. After a harsh Evanston winter, an old growth hydrangea would struggle to bloom.
Campus planners like White have started implementing the "Endless Summer" macrophylla, a bigleaf hydrangea developed to grow on both new and old wood. The Endless Summer is unique in its ability to produce flowers from blooms set before and after winter. White said she is watching both the Annabelle, which is native to the Illinois area, and the Endless Summer to see the potential impact climate change and shifting weather patterns may have on campus flora.
"Trees are the most often studied in terms of climate forward thinking," White said. "But for smaller plants, the hydrangea may be a good kind of indicator species. I think moving forward we'll see more success with getting continuous bloom over time and being able to make it through the winters."
White is not the only one interested to watch the development of flowers and shrubs on campus and in Evanston. She said there is "a lot of student interest" in participating in the landscape, leading to projects like a native woodland garden in Shakespeare Woods.
Amanda Ault, owner of Evanston floral shop FlowersFlowers, has been a gardener for over 30 years. She buys hydrangeas, which she described as a popular choice among customers, wholesale year-round. The impact climate change and shifting weather patterns have on availability in her floral business also affect her front yard.
"As we look at climate change from a gardening perspective, I think it's important for us to think about incorporating more prairie natives that are used to the dry, wet cycle," Ault said. "But it's hard to give up your hydrangeas."
Ault gardens to carry on a family legacy, growing a descendant of her maternal grandmother's peonies in her yard. For White and Camburn, it's a matter of choosing the right plants for sustainable beauty on campus.
" We are very strategic and considerate thinking about where we really invest the resources into ornamental plantings and where we just make things look nice," White said. "Right plant, right place (to) make sure that things are healthy and living. Hydrangeas are a great plant for that because they look beautiful and they are fairly low maintenance."