A little sunlight each day is necessary for the most blooms and the nicest color. Sun should only be in the early morning or late evening in hot regions (USDA zone 7 and warmer), as full shade is essential throughout the hottest part of the day. They can be grown in full sun all day in colder climes (USDA zones 4-6). On extremely hot days, they might wilt a little, but as long as they get regular watering, this doesn’t mean there’s a problem.
Water often.
All plants lose some water during the photosynthesis process, which is quite normal. Big-leaf hydrangeas, however, emit a lot of water due to their enormous leaves, thus for plants to operate at their best, irrigation or rainfall must be added. In all save the most extreme circumstances, watering every day is probably excessive; during flowering and hot weather periods, a thorough watering 1-3 times per week should be sufficient.
Mulch.
Because of their shallow roots, big-leaf hydrangeas are more susceptible to drying out and heat stress. A good 2-3″ covering of shredded bark mulch helps a plant grow more swiftly and more healthily by retaining moisture and keeping the roots cool. Pine straw or compost can also be used as a mulch, but you should avoid any kind of rock mulch because it can have the reverse effect because it retains a lot of heat.
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
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Should I prune 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. Neither of these thoughts is correct. 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.
Do bigleaf hydrangeas require direct sunlight?
Bigleaf hydrangeas can withstand temperatures as low as USDA zone 5 and as high as USDA zone 9. One reason they are so closely associated with beach places in North America as well is that they are native to warm coastal regions of Japan. The difficulty that frequently occurs in these regions is that the flower buds, which are present on the plant during the winter, might be harmed by cold. A bigleaf hydrangea plant can survive USDA zone 5 (and many even USDA zone 4). Poof if that happens! There go the blooms for the year, which accounts for the considerable amount of confusion and disappointment surrounding these lovely plants.
Your choice of sitting, or where you place a plant in your yard, can have a big impact on how well and how satisfied you are with these plants. Plant them in cold climates where they will be shielded from chilly westerly winds and weather, ideally on the east side of your home or enclosed by walls or other structures. To keep the hydrangea plant happy and stress-free in hot areas, place it where it will be entirely covered during the hottest portion of the day.
Bigleaf hydrangeas bloom again?
Hydrangea macrophylla ‘Big Daddy,’ known for its gigantic inflorescences, produces magnificent, spherical flower heads up to 14 in. (35 cm) across that are tightly packed with sky blue to pink florets, depending on the soil pH. This reblooming mophead hydrangea flowers in early to mid-summer on old growth and in mid-summer to fall on new growth, ensuring a lengthy growing season. The bushy shrub with the many flowers has glossy, dark green leaves. “Big Daddy” is ideal for the shady border as a specimen or in small groups.
Do you remove hydrangea blooms that have died?
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.