Depending on the kind you have, you must prune your hydrangeas correctly. Different hydrangea varieties need to be pruned at various times of the year.
For instance, you should hold off on pruning smooth hydrangeas like Annabelles until they are through blooming. All summer long, new blooms will result from pruning done in the late fall or early spring, before new growth starts.
Big Leaf and Oakleaf hydrangeas should only be pruned in the early fall to avoid cutting off buds that might otherwise prohibit summer blooming. It’s advisable to prune these hydrangea varieties as soon as they finish blooming.
Although Paniculata or PeeGee hydrangeas are a little more adaptable, they should still be clipped in the early spring before new growth starts.
Should you remove hydrangea tree blooms?
Your hydrangea shrubs’ blossoms appear to be withering or turning brown. No need to worry—this is merely a signal that it’s time to deadhead—remove the blossoms from the plant.
Deadheading hydrangeas doesn’t cause any damage to the plants at all. Flowering shrubs stop producing seeds when the spent blooms are removed, and instead focus their efforts on developing their roots and leaves. You will be doing your hydrangeas a favor by deadheading because this strengthens and makes plants healthier.
The right time to prune a bigleaf hydrangea.
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.
How should a limelight hydrangea tree be pruned?
Once established, limelight hydrangea trees can thrive in a variety of soil types and are drought-tolerant, making them low-maintenance and practically hassle-free.
Sun and shade
Depending on the climate zone they are cultivated in, Limelight hydrangea trees require different amounts of sunlight. They require moderate shade and around four hours of direct, unfiltered sunlight every day in zones 7-8 that are warmer. They benefit most from full sun, or at least six hours of daily direct, unfiltered sunshine, in the cooler zones 4-6.
Soil
Although limelight hydrangea trees may grow in a wide range of soil types, they prefer an acidic to neutral pH. No of the soil type, it needs to drain well. Wet feet are not good for these trees. The pH of the soil does not influence the color of the blooms like it does with certain other kinds.
In cold locations, cover the roots of your Limelight hydrangea with a 2-3 inch layer of mulch to protect them from the winter chill.
Watering
Water the soil every week to ten days to keep it consistently moist. Only water your Limelight hydrangea when the top two inches of soil are dry. Do not overwater. You can check for moisture by sticking your index finger into the nearby dirt.
Fertilizing
Every spring, before new growth, feed your Limelight hydrangea tree with a balanced, slow-release fertilizer with an NPK value of 10-10-10 made for woody plants.
Every year, before the emergence of new growth, you should prune your Limelight hydrangea tree. This can be done in late winter or early spring. To promote new growth, cut your Limelight hydrangea back annually by a third of its total height. Remember that Limelight hydrangeas only produce flowers on fresh wood, so avoid mistakenly removing any flower buds.
Trim any branches that you see that are diseased, damaged, or dead all year long.
How far back may a hydrangea tree be cut?
I have a hydrangea tree, but because the branches are excessively long, they bend downward to the ground when it rains. Can I prune branches back, and if so, when should I do it?
Yes, you can prune it, but first it’s important to define a hydrangea tree so you can understand how and why.
A panicled or PG hydrangea (Hydrangea paniculata) is actually a hydrangea tree that has been deliberately pruned to resemble a tree. Depending on the cultivar, it develops huge, elongated clusters of white or lime-green blooms at the tips of its branches in the summer that progressively turn pink or even scarlet in the fall. Since few other kinds of hydrangea have stems robust enough to create decent trees, it’s very much the only one used in this method.
The panicled hydrangea typically develops into a sizable multi-stemmed shrub. It grows an abundance of branches from its base and develops an erect, spreading shape over time, eventually reaching a height and diameter of up to 15 feet (5 meters) after 15 to 20 years. It’s obvious that it’s a shrub because it doesn’t resemble a tree in its natural state.
The nurseryman selects a young specimen with a strong central branch and starts to shape it into a hydrangea tree “prune it until it yields. He cuts off any more branches and any secondary branches that develop on the branch that will eventually serve as the trunk. During the first few years, staking is frequently required to maintain the trunk’s strict verticality. He starts trimming the top of the plant as well after the trunk has grown to the appropriate height, which is often 4 to 5 feet/1.2 to 1.5 meters. Because of this, the hydrangea is compelled to grow numerous branches at the top of a primary stem, or new trunk.
The process of making a hydrangea tree is time-consuming and significantly raises the price of the plant.
If you like, you can prune a hydrangea by yourself to resemble a tree, but it will take some time.
If you want to keep a hydrangea tree healthy, you’ll need to be prepared to prune it on a regular basis. If you don’t, the branches will grow too long and begin to bend under their own weight, as you’ve seen, and they may even break off, especially when there is heavy snow on top of them.
In your situation, it would be advisable to prune your hydrangea tree before winter because it is overgrown and the limbs are already bending from the weight of the plant. Simply prune all branches back to a distance of 6 to 8 inches (15 to 20 cm) from the top of the trunk in October or November if you don’t want them to risk breaking off in snowy or icy conditions.
Starting pruning early in the spring as opposed to the fall will help your hydrangea tree survive the winter. This is because you’ll want to keep the panicled hydrangea’s dried flower heads until spring because they are lovely over the winter.
Make it a practice to trim back all the branches early in the spring, before the leaves emerge, by 6 to 8 inches (15 to 20 cm). This will give your tree the intended effect, which is typically a ball of greenery topped with blossoms at the summit of a short trunk. Panicle hydrangeas bloom from new growth that begins to appear in mid-spring, so they will continue to bloom profusely even after harsh early-spring trimming.
In order to keep its tree-like look, with a clearly “Remove any suckers that develop at the plant’s base and any growth that develops on the trunk itself. This type of pruning is suitable for all seasons.
The optimal growing conditions for panicled hydrangeas are full sun or very little shade in virtually any well-drained soil. They can thrive in zones 3 to 8 and are cold hardy.
Shape of the Flower Head
- A paniculata type is most likely present if the flower head is formed like a cone.
- It is either a macrophylla or an arborescens kind if the flower head resembles a ball or a flat disk. Visit the section on Flower Color.
Robert Pavlis’ photograph of a hydrangea arborescens from the side, highlighting the flower’s dome-shaped crown
- A macrophylla type is present if newly opened blooms feature blue, purple, or pink blossoms.
- An arborescens type is present if the flower buds initially seem green, then turn white, and finally turn green or greenish brown as they ripen.
- You likely have a macrophylla kind if the flowers are white when they first open and remain white as they age. Although they are less common, white flowered macrophylla varieties do occur.
Note: Recent breeding is beginning to develop arborescens with flowers that have a pink tint, such as “Eco Pink Puff.” Future cultivars should have a stronger version of this pink.