Backyard Gardening
Using Hydrangeas in Holiday Decorations
By Kathryn Dorman
Several years ago, the Penn State Master Gardeners of Clinton County hosted a “Holiday Greens” workshop. My colleagues tramped through forests and swamps, collecting many different evergreens, including fir, pine, and spruce, as well as boxwood, yew, and juniper. We also obtained winterberry (deciduous holly), pussy willow, and dried hydrangea. Our workshop attendees used these cuttings to create their own holiday decorations. This year, I used hydrangea cuttings, donated by a friend, in making wreaths for my church (see Photo 1). I decided to research hydrangea species for planting on our church grounds.
According to the Chicago Botanic Garden, there are about 50 worldwide hydrangea species belonging to the Hydrangeaceae family (https://www.chicagobotanic.org/sites/default/files/pdf/plantevaluation/no47_hydrangea.pdf). At least four species of hydrangea are grown by gardeners in the United States. Smooth hydrangea (Hydrangea arborescens) and oakleaf hydrangea (H. quercifolia) are native to North America. Panicle hydrangea (H. paniculata) and bigleaf hydrangea (H. macrophylla), are native to Eastern Asia and Siberia. These species are all deciduous shrubs (relatively short, woody plants with multiple stems growing out of the ground). Another species, H. anomala subsp. petiolaris, is actually a climbing vine, reaching heights of 50 feet. For more information on these hydrangea species, visit Iowa State University’s Extension and Outreach website (ISU/EO) at https://hortnews.extension.iastate.edu/hydrangeas-iowa.
Hydrangea species typically prefer rich and moist, well-drained soils. They will grow in full sun to partial shade. Hydrangeas will tolerate acidic soils, but according to Wildflower.org, some species will experience chlorosis, or loss of green leaf color, if the soil is too alkaline (https://www.wildflower.org/plants/result.php?id_plant=HYAR).
Hydrangea leaves are simple and opposite. Most species have oval or rounded leaves with notched edges. An exception, as its common name implies, is oakleaf hydrangea, which has lobed leaves. The leaves of most hydrangea species will turn yellow in the fall, but oakleaf hydrangea leaves will turn red.
All hydrangea species produce clumps of flowers, which are often white at some point in the growing season. The hydrangea flower masses will contain larger, showy flowers and smaller, inconspicuous flowers in varying proportions, depending on the species and variety. They may be called ‘mopheads’ or ‘lacecaps,’ based on the distribution and amounts of large and small flowers. Many species and cultivars of hydrangea will flower throughout the summer. They may begin with light green blossoms, which turn white, and often transition to shades of pink or red (https://extension.psu.edu/take-a-look-at-hydrangeas). There are some varieties, especially of smooth hydrangea, that will retain the white flower color until it fades to tan or brown in autumn.
The blue or pink flower clusters that are often used as cut flowers are produced by bigleaf hydrangea. Bigleaf hydrangea is “the only hydrangea species where the flower color depends on soil pH – blue in acidic soils and pink in alkaline soils (ISU/EO).”
Pruning time is important for producing flowers. Smooth and panicle hydrangeas produce flowers on new growth, and can be pruned back in late winter or early spring. Smooth hydrangeas can be pruned down to the ground every year. Annual pruning to the ground for panicle hydrangeas will limit the plant’s height. Occasional selective cutting of the taller branches may, however, rejuvenate the entire plant.
Oakleaf hydrangea and older cultivars of bigleaf hydrangea only bloom on old growth from the previous year. Newer cultivars of bigleaf hydrangea will bloom on both old and new growth. It is probably safest to prune out only the dead limbs, and only after both of these species leaf out in the spring (ISU/EO).
If you decide to purchase a hydrangea, carefully read the catalog or label information. Look for cold hardiness to Zones 5 or 6 (or lower) for Clinton County. Determine the flower color or colors you want, which can vary even within a species. Look for the earliest bloom time, which can also vary. If you have your heart set on pH-dependent flower color, look for bigleaf hydrangea varieties (H. macrophylla). Be aware that you will have to monitor and amend the soil pH to maintain the desired color.
I personally like the natural colors of some smooth, oakleaf, and panicle hydrangeas. When they are cut at just the right time, there are a myriad of shades, including white, green, pink, and even magenta (see Photo 2). Some people spray-paint hydrangeas to include in their arrangements. This could be colorful as well as useful, especially if it would help to keep the flower heads intact. Even just a slight breeze is enough to dislodge petals, and can make quite a mess. Hydrangeas bring a special kind of beauty to seasonal arrangements, however, so I think they are worth including in decorations!
Kathryn Dorman has been a Penn State Extension certified Master Gardener in Clinton County since 2017. She can be reached at clintonmg@psu.edu, or through the Clinton County Master Gardener Hotline at (570) 858-0198.
