Plants of the Week: June 24

Guest Author: Ben Hitz – summer intern

Hydrangea macrophylla ‘Hamburg’ (bigleaf hydrangea)

The thing that struck me about the H. macrophylla ‘Hamburg’, located in the Hydrangea Collection, is the variation of colors on the blooms of a single plant. The compact flower clusters range from deep rose-pink to purple-blue. The flower color can be changed by amending the pH of the soil. Adding sulfur to increase acidity will make the flowers bluer, while adding lime to increase alkalinity will make the flowers pinker. H. macrophylla ‘Hamburg’ boasts a long bloom time from early to late summer. This deciduous, bushy shrub grows 4-5’ wide and prefers full sun to part shade in well drained soils. Photo credit: B. Hitz

Liquidambar styraciflua ‘Slender Silhouette’ (sweetgum)

Liquidambar styraciflua, commonly known as sweetgum, is a deciduous shade tree native to the eastern United States and parts of Mexico. The sweetgum is a sun-loving, low-maintenance tree that tolerates a wide variety of soils. It features star-shaped green foliage with 5 to 7 pointed lobes. Fall color is a mixture of brilliant yellows, oranges, and purples.

The only drawbacks of L. styraciflua are its infamous gumballs. These hard, spiky fruit clusters can cause a mess and pose an ankle-rolling hazard when planted near a sidewalk. The ‘Slender Silhouette’ cultivar, located in the Scott Entrance Garden, is a narrow, upright tree that will not shade out other plants and is an excellent accent for gardens. Photo credit: B. Hitz

Cercis canadensis ‘Ruby Falls’ (eastern redbud)

One of the highlights of the Isabelle Cosby Courtyard is the Cercis canadensis ‘Ruby Falls’. This pendulous cultivar of C. canadensis features an elegant, compact weeping form, and ruby red heart-shaped foliage in the spring that transitions to green as the summer progresses. Pink flowers adorn the branches for several weeks during early to mid spring. Growing only 6’ tall and 4’ wide, this tree is perfect for small gardens. C. canadensis ‘Ruby Falls’ is easy to grow and does well in full sun to part shade in well drained soils. Photo credit: B. Hitz