Occasionally, fellow hydrangea enthusiasts (Hydrangea macrophylla cvs. and H. serrata cvs., USDA Hardiness Zones 59) get in touch with me and share their sorrow over a valued shrub that has failed to bloom. They have eagerly waited to see if this summer will see the appearance of their mophead or lacecap blossoms, but have been disappointed. This issue is rather typical and is simply fixable. They only need to be aware of how these wild plants develop and choose types that can withstand their local climate. The best new hydrangeas are here.
Avoid too much shade and too much nitrogen
When it comes to hydrangeas that won’t bloom, two words to keep in mind are “too much. In most regions of the United States, bigleaf hydrangeas thrive in the shade; nevertheless, excessive shade can produce stunning foliage without any flowers. In the East, Midwest, and Northwest, bigleaf hydrangeas thrive in the intense shadow produced by deciduous trees or evergreens. Any shade you can find in California—as long as it is not too dense—seems to be effective. However, hydrangeas in northern and coastal regions of the country don’t need any kind of shade at all.
You may be pruning your hydrangea at the wrong time if it isn’t blooming. Learn about hydrangea pruning.
Too much fertilizer could also be a concern. A fertilizer with a high nitrogen content will produce lovely leaves but few, if any, flowers. Use caution when fertilizing bigleaf hydrangeas because they may withstand extremely high quantities of fertilizer without developing fertilizer burn. Lack of flowers can also be caused by excess moisture and aridity.
Hydrangea macrophylla and serrata cvs.
These plants are indigenous to Japan and are found in deciduous woodlands. Between the two species, there are more than 400 cultivars that are known. USDA Hardiness Zones 5 through 9. Depending on where you live, they thrive in either full sun or light shade. They do well in moist, well-drained soil, but in extremely alkaline soils, they can produce yellow leaves, a sign of chlorosis. PROPAGATION: Take softwood or semi-hardwood cuttings in the late spring or early summer to propagate new plants. In the early spring, prune dead wood from shrubs. The good growth from the previous year should not be pruned, as blossoms thrive on old wood. Plants grow from three to six feet tall, but wind and cold weather can harm the plants and reduce the growth of the shrubs as a whole.
Bigleaf hydrangeas grow how quickly?
Your hydrangeas’ development pace will depend on a variety of elements, such as the environment, sunlight exposure, watering, and fertilizer.
With some types growing an average of 25 inches per year until they mature, hydrangeas are categorized as having quick growth. Other hydrangea species, including the Hydrangea paniculata, have an annual growth rate of up to 2 feet.
With canopies that are 18 to 20 feet broad and that can grow to heights of 10 to 15 feet, some paniculata types can be classified as tree forms.
Knowing in advance how big a certain hydrangea cultivar can go is crucial when designing your garden, especially since some kinds can quickly take over the space you offer them.
This will enable you to designate enough room for it in your yard, or if you don’t have enough space, just pick a lesser kind.
Are huge leaf hydrangeas sun-sensitive?
In Georgia, bigleaf hydrangeas, Hydrangea macrophylla, sometimes known as French, Japanese, or snowball hydrangeas, are grown both as landscape and florist plants. Bigleaf hydrangeas are frequently bought as gift plants from florists and can be moved to the landscape for yearly blooms. By modifying the soil pH, homeowners can alter the color of flowers from pink to blue or from blue to pink.
Two Main Groups
In the nursery industry, bigleaf hydrangeas come in more than 500 different cultivars. They can be split into two main categories: hortensias, which have huge flower clusters resembling snowballs, and lacecapes, which often have flowers with fairly flat tops, fertile blooms in the center, and showier sterile flowers on the periphery.
Location
Bigleaf hydrangea prefers moist, well-drained soil, morning light, and afternoon shade. Don’t plant it in exposed, hot, dry areas. Winter and late spring can cause cold damage to the buds, so be ready to offer some winter protection by wrapping the plant in an old sheet, blanket, or cardboard box when the temperature drops below freezing. Additional effective cold protection is offered by a cylinder of chicken wire surrounded by leaves.
Bigleaf hydrangea is a great patio plant that is simple to cultivate in containers. The ability to bring the plant indoors on a chilly night is another benefit of growing it in a container.
Planting
Prepare the soil over a large area if at all possible. Apply 50 pounds of decomposed organic material per 10 square feet and thoroughly work it with a tiller or shovel into the top 8 to 12 inches of soil. Organic matter keeps nutrients and water in the soil and protects plants from stress caused by changes in soil moisture from wet to dry.
Before the plant is established, don’t fertilize (4 to 8 weeks after transplanting). Since Georgia’s soils tend to be acidic, the first blossom color will probably be blue.
After transplanting, make sure the root ball’s top is flush with the soil’s surface and give it a good drink of water. To retain moisture and manage weeds, add 3 to 5 inches of an organic mulch to the soil’s surface, such as pine straw, pine bark, or fallen leaves.
Fertilization and Watering
Throughout the growing season, bigleaf hydrangea responds to many sparing fertilizer applications. It is advised to apply a general-purpose fertilizer, such as 8-8-8 or 10-10-10, at a rate of 1 pound (2 cups) per 100 square feet in the months of March, May, and July. When fertilizing, it is not required to remove the mulch; however, watering soon after application will help the fertilizer dissolve and go into the soil.
Bigleaf hydrangea is a water-hungry plant that does best in landscape zones with moderate water requirements. When the plant starts to wilt in the absence of rain, water it. Avoiding plant stress during the spring, when the blooms are developing, is especially crucial.
Flower Color
According to research, the presence or absence of aluminum compounds in the flowers is the real cause of color variation. The color is blue if aluminum is present in the plant. If it’s absent or only minimally present, the blooms are pink, and if it’s there, the color is “in between.”
Through influencing the amount of aluminum in the soil, soil pH indirectly influences flower color. Aluminum is typically more accessible to the roots in soil that is acidic (pH 5.5 or lower). Alkalinity (pH 7.0 or above) in the soil reduces aluminum availability and increases the pinkness of the blooms.
Distribute 1/2 cup of wettable sulfur per 10 square feet and water it in to gradually turn pink flowers blue. Spread one cup of dolomitic lime per 10 square feet and soak it into the soil to turn the flowers pink. The effects of this treatment on flower color could not be visible for a year.
Through liquid soil drenches, you can change the color of your flowers more quickly and easily. In March, April, and May, saturate the soil around the plant with 1 tablespoon of alum (aluminum sulfate) dissolved in 1 gallon of water to make the blossoms blue, or perhaps more blue. In March, April, and May, soak the soil surrounding the plant with a solution of 1 tablespoon of hydrated lime in 1 gallon of water to turn the blossoms pink. Avoid getting the mixture on the leaves to prevent foliar damage.
Failure to Flower
Bigleaf hydrangeas can have problems with flowering failure. This may be brought on by winter damage to the flower buds, overly-shady plant growth, an excess of nitrogen fertilizer, or untimely pruning. Pruning throughout the late summer, fall, and winter will eliminate prospective blossoms since bigleaf hydrangeas develop their flower buds in the late summer for the next year.
Pruning
When the bigleaf hydrangea’s blossoms start to fade, prune it. To promote branching and fullness, remove blossom heads and head back other shoots as appropriate. Avoid pruning after August 1 since flower buds for the following season will start to grow in late summer.
After a difficult winter, it may be necessary to prune plants to remove damaged foliage. The removal of winter-damaged leaf is healthier for the health of the plant and its aesthetically pleasing appearance, even though it will promote vegetative growth at the expense of flowering.
Propagation
Softwood cuttings collected in the early summer can be used to multiply bigleaf hydrangeas. Choose terminal cuttings from shoots that are not in bloom. A minimum of three leaves and a length of 3 to 5 inches should be present on each cutting. Make a little angle cut at the node (where the leaves are joined), then dip the cut end in a rooting hormone and plant it in a moist growing medium. To prevent wilting and dehydration, propagators frequently cut off the top half of each leaf. While the cuttings are rooting, keep them wet and in a shaded environment.
Layering is another method of bigleaf hydrangea propagation in the landscape. This is accomplished by excavating a trench close to the plant and bending a branch downward into the trench. At the point where the limb touches the ground, use a knife to carefully remove a narrow band of outer bark that is about an inch broad. After that, bury the limb in dirt, leaving 6 to 12 inches of the growth at the tip exposed. The new plant should be ready for transplantation the following winter if layering is done in the summer.
Early spring is a good time to separate clumps of mature, older hydrangeas with a shovel. A cluster that has been there for a while can produce many plants.
For More Information
On hydrangeas, there are several top-notch books accessible from publishers and online. Dr. Michael Dirr, a former professor at the University of Georgia, is the author of the book Hydrangeas for American Gardens. Both online and in bookstores, it is widely accessible. Additionally, the U.S. National Arboretum offers a fantastic online resource for choosing and growing hydrangeas. To learn more, visit www.usna.usda.gov/Gardens/faqs/hydrangeafaq2.html.
Associate in public service and coordinator of the state’s master gardening program; consumer ornaments
Have a concern?
To learn how our group of county agents can help you, get in touch with your nearby UGA Extension office.
What hydrangeas have large leaves?
There are numerous cultivars of the bigleaf hydrangea group (Hydrangea macrophylla) that bloom profusely and endure for many years in the garden. Many of the newest cultivars have neat, compact tendencies and more reliable reblooming patterns. Additionally, you’ll notice bicolor blooms, more vibrant stems and foliage, and earlier bloom times. Here are seven hydrangea cultivars with a range of outstanding qualities, from old to new.
Do you wish to discover how to develop bigleaf hydrangeas? For quick suggestions on how to make your plants flourish, see our post How to care for your bigleaf hydrangeas.
A marvel in any garden, the exquisite, light-blue lacecap blooms of “Blue Billow” are among the most cold-tolerant (to USDA zone 4). But this 4-foot-tall variety is also one of the early-summer hydrangeas to bloom. And in complete shade, it blooms cheerfully.
It’s difficult to find a plant that can withstand both scorching heat and freezing temperatures (cold-hardy in USDA zones 4 to 9), but that’s precisely why you can depend on this resilient, hardy hydrangea to bloom each year. As Bloomstruck blooms again and again during the summer, it is covered in spherical clusters of 4- to 5-inch vibrant pink to periwinkle blue flowers. They are little, standing about 3 to 5 feet tall, and they look excellent in bigger containers.
These plants, whose names include Cityline Berlin, Paris (as seen in the photo), and Venice, only grow to a height of 1 to 3 feet. They thrive in pots or very small beds, in the sun or partial shade, on decks and patios. In spite of the plants’ little size, the pink or blue mophead flowers are comparable in size to those of their taller relatives.
This 3- to 5-foot-tall plant thrives in either sun or partial shade and has bright green leaves with a white edging that dazzle. Light-O’Day has stunning two-tone lacecap flowers that bloom in either pink or blue depending on your soil type, in addition to lovely foliage.
Additionally marketed as “Firelight” or “Lighthouse,” Lichtfeuer. This variety’s dark rose-red blooms are unusual for hydrangeas and remain crimson even in acidic soil. On 4-foot plants, the massive 8-inch-diameter mophead flowers bloom in the middle of the summer.
Blushing Bride, like the first plant in this collection, blooms on both old and new wood, guaranteeing recurrent blooms. But rather than being pink or blue, these semidouble blossoms bloom in a wonderful light pink as they age. This 3- to 5-foot-tall plant has dark-green, mildew-resistant leaves. Mulch around the plant, especially during the first season, to ensure even moisture distribution.
The majority of bigleaf hydrangeas are mopheads, but certain varieties, like Let’s Dance Diva! above, are lacecaps. This kind features more spectacular flowers surrounding a center of florets, or tiny flowers. Let’s Dance Diva! is a reblooming hydrangea that only grows 2 to 3 feet tall and broad but boasts enormous 7 to 10-inch-wide pink or blue flowers depending on the pH of the soil. It can withstand cold temperatures in USDA zones 5 to 9.