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.
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Do I need to trim my bigleaf hydrangea?
Consider when your hydrangea blooms to see if it grows on old wood. These shrubs typically start blooming in the early summer and stop by midsummer, however isolated blooms may continue into the fall. Late summer or early fall, when the days grow shorter and the temperature drops, these shrubs begin to create the bloom buds for the following year. Pruning should be done just as the flowers start to fade to limit the chance of eliminating these buds. The sooner the shrub recovers after bloom, the more and bigger flowers it will produce the next season.
1. Old blossoms should be taken out to tidy up.
Gardeners can remove any wayward or straggly canes at the soil level and prune wasted blooms just below the flower head to keep their plants looking clean.
2. Eliminate the oldest canes to increase vigor.
A hydrangea may produce lesser blooms as it ages and becomes woody. The shrub will remain healthy and continue to produce big, many flowers if a few of the oldest canes along the soil line are routinely removed. The same technique, which involves removing the tallest canes, can prevent a shrub from becoming too tall.
Watch a video on pruning bigleaf hydrangeas
Almost everyone is mesmerized by bigleaf hydrangeas’ mophead blossoms (Hydrangea macrophylla and cvs., Zones 49). And it appears that queries regarding pruning these flowering bushes are common among gardeners. Because they are shrubs, it is frequently assumed that they require pruning. Some gardeners believe that pruning their hydrangea will encourage it to bloom. Both of these ideas are incorrect. Bigleaf hydrangeas don’t require any pruning, and if you prune them, you risk removing the bloom buds you were trying to receive by timing your cuts improperly.
The flower buds on bigleaf hydrangeas are often found on growth from the previous season, which is known as “old wood.” You will be removing the flower buds if you prune them before they bloom. Pruning too early doesn’t stop the entire display; rather, it stops a large chunk of it for many newer types that really generate buds on both old and new wood. However, if your hydrangea isn’t blooming, improper pruning is frequently to blame. Just after the bigleaf hydrangea has finished flowering is the ideal time to prune it. The shrub will have plenty of time before winter to establish new growth and harden off.
This video will provide you with the knowledge you need to timing your cuts properly and pinpoint where to make them on the shrub if you feel that pruning your bigleaf hydrangea is necessary. Only hand pruners and possibly a pair of loppers to reach deep into the hydrangea will be required of you. Wearing safety eyewear is also advised. While trying to gaze down into the shrub, it is quite easy to poke your eye on a stem, even if you don’t think they are cool. A poke in the eye is also never appropriate.
How can I encourage my bigleaf hydrangea to bloom more?
Smooth hydrangeas (Hydrangea arborescens), which get their name from the texture of their huge leaves, are more well-known for their massive, spherical, white flower heads. The most popular type, “Annabelle” (also known as Snowball Bush), was identified as coming from Anna, Illinois, by a horticultural expert in the 1960s. The ‘Annabelle’ hydrangea displays large, pure-white blooms that gradually turn green. A more recent cultivar, Invincibelle Spirit, blooms pink rather than the usual white. The smooth hydrangea, which is native to parts of North America, starts blooming in late June and keeps periodically flowering all summer long. In zones 4 through 9, it thrives in sunny or slightly shaded environments.
How to Get More Smooth Hydrangea Flowers:
- If the soil is damp, grow smooth hydrangeas in full sunlight. (Spots that occasionally dry out benefit from partial shade.)
- In droughts, especially in the sweltering summer, water them.
- soil amendment using organic matter (such as compost).
- In the early spring, soon as new growth begins to appear, trim back stems.
Are bigleaf hydrangeas deadheaded?
According to Meyers, the species of hydrangeas will determine the optimal time to prune them. When the initial set of flowers emerges from the previous year’s growth in the spring on bigleaf hydrangeas like Endless Summer, she advises, “deadheading to remove the faded blossoms before the next flush arises.” As long as the cut is made before July or August, when the plant starts to create buds for the blooms of the following year, you can make a deeper cut for a longer stem. She advises removing the faded blooms off smooth hydrangeas as soon as they turn green in order to guarantee a second flush of smaller flowers in the fall.
What occurs if hydrangeas are not pruned?
Hydrangeas can eventually resemble a tangled jumble of woody stalks if they aren’t pruned, and their flowers will get smaller and less beautiful as a result. Lack of pruning is frequently the cause of your hydrangeas’ failing to bloom.
Regular pruning of hydrangeas promotes new growth and a better display of blooms while also helping to keep them in form.
The experts at Thompson & Morgan say that “it’s this vigorous, new growth that ensures you have lots of huge, healthy flowers to enjoy in the years to come.”
On aged wood, do bigleaf hydrangeas bloom?
Many gardeners, both novice and expert, are confused about how to prune hydrangeas. Determine which species are present in your garden before you even consider getting your trimming equipment. In New Hampshire, hydrangeas come in a variety of kinds, and each one has quite distinct growth patterns and pruning needs. Some plants only produce flowers on fresh growth, while others mostly produce flower buds on older wood. To learn when and how to prune your hydrangeas, refer to the short guide below.
The type of hydrangea that most gardeners are most familiar with is the bigleaf variety. Bigleaf hydrangeas, often known as mopheads or lacecaps, are distinguished by their glossy, dark green foliage and enormous, vibrant blooms. In New Hampshire, it might be difficult to get them to flower because they often grow on old wood. A plant may have luxuriant foliage but no blooming buds because of the cold winter temperatures and drying winds.
At the tops of stems on old wood from the previous year, flower buds are created. Although lower buds along the stem have the capacity to grow blooms as well, the hydrangea’s blossoming potential is decreased if those buds are died or damaged throughout the winter. Wait until new growth sprouts in the spring before pruning your bigleaf hydrangeas. Approximately 1/4 inch above the first group of live buds, prune the plant. A hint: the interior of living stems will be green, whereas the interior of dead stems will be brown. Cut completely dead stems flush with the base.
Consider replacing your bigleaf hydrangea with a “remontant (reblooming) variety if you have difficulties getting it to bloom consistently year after year. In recent years, a number of cultivars that blossom easily on fresh shoots have been introduced.
Bigleaf hydrangeas and mountain hydrangeas have a striking resemblance and are closely related. Compared to their relative, mountain hydrangeas have more delicate branching and less ostentatious blossoms. Because flowers only grow on old wood, wait to prune stems until the spring when new growth starts and you can identify which buds are still healthy.
Native to Eastern North America, smooth hydrangeas fit in well with most gardens in New Hampshire. They have mounded growth patterns and mid-summer blooms of white to pale pink flowers. Smooth hydrangeas, in contrast to bigleaf and mountain varieties, bloom on young wood and may withstand severe pruning. From late winter until early spring, you can remove dated flowers from the previous year. The flowers on old stems will bloom, but they will be modest. In the spring, trim stems all the way to the ground for bigger, more vigorous blossoms.
The panicle hydrangea is without a doubt the most popular variety planted in New Hampshire. It is extremely cold hardy and blooms consistently from season to season. It develops into a tall, low-branched little tree or broad shrub, with branches that frequently arc under the weight of its numerous, enormous conical blooms. Panicle hydrangeas should be clipped in late winter or early spring before the emergence of the leaves because they blossom on new growth. To enhance the general structure and habit of the plant, remove wasted blossoms and prune. Make cuts to the branch collar of stems or one quarter inch above living buds.
The Southeastern region of the United States is home to oakleaf hydrangeas. Despite the possibility of winter damage and flower bud loss in northern gardens, this shrub’s eye-catching foliage and exfoliating bark are sufficient reasons to cultivate it. Removing dead or broken branches should only be done in the spring because oakleaf hydrangeas also bloom on old wood. Oakleaf hydrangeas often don’t need a lot of pruning. After fresh growth has started, thin stems as necessary and shorten the plant’s height.
By making simple trimming mistakes, many well-intentioned gardeners lower the potential blooming of their hydrangeas. Fortunately, hydrangeas are actually pretty easy to maintain as long as you are aware of their growth patterns and adhere to these straightforward pruning instructions.