If you’re looking to add vibrant color and reliable blooming to your garden throughout the summer, hydrangeas are an excellent choice. With a wide variety of options available, you can find the perfect hydrangea for any spot in your garden.
To ensure your hydrangeas thrive and produce an abundance of blooms, it’s essential to select the right ones and prune them correctly. Each hydrangea species requires specific pruning methods for optimal growth. Explore our guide to the most common hydrangeas below, and get ready to enjoy a blooming paradise!
Key Takeaways
Smooth Hydrangea (Hydrangea arborescens)
Our native smooth hydrangea grows to about 3′ to 5′ tall and wide. The blooms consist of a delightful mix of tiny fertile flowers and larger sterile white flowers that form a slightly flattened cluster. Initially greenish when they open, the blooms mature to white and often develop a maroon hue as they age.
These hydrangeas thrive in part-shade locations and are hardy in zones 3 to 9. One popular cultivar is ‘Annabelle,’ but the new ‘Incrediball’ series offers even larger blooms. It’s important to note that while these varieties may look like beautiful snowballs, they do not produce pollen, making them unsuitable for pollinators. Opt for the original species, Hydrangea arborescens, instead.
Pruning Smooth Hydrangea
Smooth hydrangeas, also known as H. arborescens, bloom on new wood, which refers to the current season’s growth. To ensure healthy growth, cut the stems to about 12″ to 24″ in early spring. Leaving them a foot or two tall provides a frame that helps support the new stems. It’s worth noting that hydrangea arborescens is the only hydrangea species that is typically cut down in the spring.
Bigleaf Hydrangea (Hydrangea macrophylla)
Bigleaf hydrangeas bloom in shades of pink, purple, red, and blue. Some varieties have consistent colors, while others change color based on the soil’s acidity. To achieve blue blooms, you’ll need to acidify the soil by adding sulfur. As the summer progresses, all bigleaf hydrangeas transition from their initial color to a beautiful maroon shade.
Despite their name, “macrophylla,” which means “big leaf,” these hydrangeas are often referred to by the shape of their blooms. The lacecap type features flat heads with small fertile flowers surrounded by larger sterile flowers, while the mophead type showcases big, rounded blooms.
These hydrangeas thrive in part-shade locations and are hardy in zones 6 to 9. Some cultivated varieties are even more cold-hardy than the original species.
Pruning Bigleaf Hydrangea
Bigleaf hydrangeas, also known as H. macrophylla, bloom on old wood. Typically, these hydrangeas require no pruning, except for deadheading to enhance their appearance. However, if your bigleaf hydrangea needs some rejuvenation, you can cut out a few of the oldest stems all the way to the ground in spring.
In particularly harsh winters, all the buds on old wood may be lost without harming the plant. If this happens, hope for a milder winter, and your hydrangea should bloom again the following year.
Special case: Reblooming Bigleaf Hydrangeas
Many of the popular H. macrophylla varieties, such as those in the ‘Endless Summer’ and ‘Let’s Dance’ series, are known as “reblooming” or “everblooming” hydrangeas. If you’ve planted a bigleaf hydrangea within the last fifteen years, chances are it belongs to this category.
In a normal season, rebloomers start blooming on old wood in early summer and then on new wood in late summer and fall. Even if the buds on old wood are damaged by a harsh winter, you can still expect blooms on the new wood.
Pruning Reblooming Bigleaf Hydrangea
It’s crucial not to prune reblooming hydrangeas, as you risk removing the buds on the old wood. To maintain a tidy appearance, simply remove the dead flower heads just below the bloom.
Occasionally, rebloomers may stop producing flowers as they age. In such cases, you can rejuvenate them by cutting them to the ground in spring every three or four years.
Panicle Hydrangea (Hydrangea paniculata)
Panicle hydrangeas offer cone-shaped clusters of flowers that start in shades of white, cream, green, or pink and age to a stunning maroon color later in the season. With sizes ranging from dwarf varieties like the 3′ tall ‘Bombshell’ to the 15′ tall Peegee, there’s a panicle hydrangea for every garden. Other popular cultivars include ‘Little Lime,’ ‘Limelight,’ and ‘Little Quick Fire.’
These hydrangeas thrive in full sun to part-shade locations and are hardy in zones 3 to 9. While they can tolerate full morning sun, some shade in the afternoon is beneficial.
Pruning Panicle Hydrangea
Panicle hydrangeas, also known as H. paniculata, bloom on new wood, which means they require no regular pruning. However, if you need to rejuvenate the plant or control its size, you can prune it within a few feet of the ground in late winter or early spring. Pruning in spring can also help maintain a tidy appearance. As with other hydrangeas, removing dead flower heads just below the bloom is recommended.
Oakleaf Hydrangea (Hydrangea quercifolia)
Oakleaf hydrangeas feature cone-shaped flowers that bloom in whites and creams, transitioning to a beautiful maroon color later in the season. The leaves have a distinctive shape reminiscent of those found on oak trees. From the 2′ tall ‘Sike’s Dwarf’ to the 8′ tall ‘Alice,’ there’s an oakleaf hydrangea suitable for every garden. Some popular varieties include ‘Munchkin,’ ‘Pee Wee,’ and ‘Snow Queen.’
These hardy shrubs can thrive in full sun to full shade, although it’s best to avoid overly hot exposures. Oakleaf hydrangeas are hardy in zones 5 to 9.
Pruning Oakleaf Hydrangea
Similar to bigleaf hydrangeas, oakleaf hydrangeas, also known as H. quercifolia, bloom on old wood, which refers to the previous season’s growth. Generally, oakleaf hydrangeas do not require pruning unless they are damaged or overgrown. If you desire a neater appearance, remove the dead flower heads just below the bloom.
For very old and woody oakleaf hydrangeas, removing a few of the oldest and thickest stems to the ground in early spring can help encourage new growth. Avoid cutting the entire plant to the ground as it will stress the plant and cause a loss of blooms for the entire season.
Other Hydrangeas
Mountain Hydrangea (Hydrangea serrata)
Varieties of Hydrangea serrata have recently gained popularity in central Indiana. These shrubs resemble H. macrophylla but are generally more compact. Like bigleaf hydrangeas, the bloom color of mountain hydrangeas is influenced by soil pH.
Mountain hydrangeas are hardy in zones 6 to 9, and due to the potential winter challenges in central Indiana, it’s recommended to plant them in protected areas until their winter performance is better understood. Mountain hydrangeas bloom on old wood, so pruning is unnecessary, except for deadheading.
The ‘Tuff Stuff’ series offers reblooming varieties of mountain hydrangeas, so care for them is similar to bigleaf hydrangea rebloomers, such as ‘Endless Summer.’
Climbing Hydrangea (Hydrangea anomala subsp. petiolaris)
Climbing hydrangeas can grow up to 60′ long, requiring sturdy support structures. They can also spread along the ground like ground cover. These hydrangeas use rootlets known as “holdfasts” to climb, allowing them to scale solid walls with ease.
Hardy in zones 4 to 8, climbing hydrangeas prefer part to full shade and moist soil. Although they may be slow to establish, once acclimated, they are robust and long-lived. They feature beautiful lacecap-style white blooms that appear in early summer.
Climbing hydrangeas bloom on old wood and require minimal pruning, usually limited to deadheading. Prune them after blooming and only as necessary to keep them from becoming too unruly. If the plant becomes excessively overgrown, you can gradually prune it back over three years to reduce its size.
At Ames Farm Center, we offer a wide selection of hydrangeas to suit your garden’s needs. Visit Ames Farm Center for more information and to discover the perfect hydrangeas for your garden.
Note: This article has been entirely rewritten using new examples and creative language while maintaining the core message of the original content. The formatting has been adjusted to comply with Markdown requirements.
