How To Get Big Leaf Hydrangeas To Bloom

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.

Many customers ask why their hydrangeas aren’t blooming. The primary reasons hydrangeas don’t bloom are incorrect pruning, bud damage due to winter and/or early spring weather, location and too much fertilizer.

There are hydrangea kinds that bloom on either fresh or old wood, or even both. Both new and old wood are the growth of the following year (spring), respectively.

  • Consider that this year, you bought a Nikko Blue Hydrangea. For the next year, Nikko’s produce blooms in the fall. Your Nikko is therefore creating blooms this fall that will blossom in the spring.
  • Therefore, you wouldn’t want to completely prune your Nikko Blue Hydrangea this fall while you are pruning your perennials. Pruning the Nikko Blue Hydrangea this fall would effectively mean cutting off your hydrangea flowers for the upcoming spring.
  • The idea behind Endless Summer, a hydrangea variety that blooms on both old and new wood, is that the plant will set blooms this fall to blossom not only in the spring of the following year, but will also keep producing blooms in the spring of the following year to extend the blossoms into the summer.
  • Once more, pruning your Endless Summer hydrangea in the fall would mean removing some of the flowers that would blossom in the spring.

The hydrangea’s plant tag will indicate whether it blooms on fresh wood, old wood, or both. It is typically preferable to wait until spring to prune your hydrangeas. As the plant grows, you’ll see stems that are fragile when bent and lack any leaves. Since these stems are dead and won’t produce any flowers, they should be clipped close to the plant’s base.

The second reason why your hydrangeas aren’t blooming is probably the weather. Buds of hydrangeas are extremely susceptible to cold. Therefore, it is a good idea to wrap your hydrangea for the winter if it is an old wood hydrangea. Keep in mind that old wood hydrangeas establish their blooms for the following spring in the fall. Therefore, you won’t have blossoms in the spring if the fall-produced buds are frozen in the winter.

You can wrap anything with regular burlap. Burlap should be wrapped around the plant and filled with mulch or leaves after the first hard frost and after the hydrangea’s leaves have dropped. In order for the buds to survive the winter and sprout the following spring, the plant receives insulation from this. Never wrap your hydrangeas in plastic. When warmer winter days arrive, the plant cannot breathe since plastic, unlike burlap, doesn’t breathe. As a result, the plant can heated to such high temperatures that it cooks within the plastic and perishes.

The second most frequent weather-related cause hydrangeas do not blossom is late spring killing frosts. We saw really chilly temperatures in April both this year and last year after beautiful spring days. When springtime temperatures drop below freezing, hydrangeas need to be covered with an old beach towel or sheet. Because of the temperature dip, there won’t be any blossoms.

The majority of hydrangeas require at least 3 to 4 hours of light per day to bloom. The best light is in the early morning, midday light is acceptable if it is dabbled light rather than beating sun, and afternoon sun is typically too hot. Check the plant label, though. Newer hydrangea cultivars are being created that can withstand more sun exposure time and sun intensity. A hydrangea in full sun will require much more watering than one in diffused light, so keep that in mind.

High nitrogen fertilizer should not be used to feed hydrangeas. Nitrogen is indicated by the first number on the fertilizer ratio. (The ratio stands for N, P, and K) For healthy leaves and general good growth, some nitrogen (N) is required; however, a ratio of 8-16-6 or any similar combination with a higher middle or phosphorus (P) value is preferred. The growth of roots and shoots is encouraged by phosphorus, which improves the blooming process.

Potash (K), the third element’s last quantity and the lowest ratio, is for plant hardiness. Because hydrangeas prefer acidic soil, they can be fertilized with fertilizers designed for such plants. Hydrangeas only require fertilizing twice a year, once in early spring and once in mid-summer. To avoid root burn, make sure the soil is always moist before applying a fertilizer.

What should I feed hydrangeas to encourage blooming?

When purchasing fertilizer, check the labels to see how much nitrogen (N), phosphate (P), and potassium are present (K). A general-purpose, balanced fertilizer such a 10-10-10 N-P-K or 12-4-8 N-P-K is typically best for hydrangeas. Consider using a fertilizer with additional phosphorus if you want your hydrangea blossoms to be bigger and more numerous.

Since phosphorus is the middle element, fertilizer with the formula 10-20-10 will do. Choose a slow-release granular fertilizer with the designation “bloom boost” if you’re looking into it because it might also include more phosphorus.

Big leaf hydrangeas produce flowers?

One of the most well-liked hydrangeas in our gardens is Hydrangea macrophylla (Big Leaf Hydrangea), which is native to Japan. This deciduous shrub has a rounded form, big, strong leaves, and lovely clusters of June flowers that bloom for a long time. The Mophead Hydrangeas and the Lacecap Hydrangeas are the two subspecies that make up the species.

  • Large, spherical flower heads covered largely in showy, sterile florets are produced by Mophead Hydrangeas or Hortensias. The blooms will continue to bloom nonstop throughout the summer, for a period of three to six months, until October arrives and they begin to change color. Rich blues that turn wine-red can be quite spectacular, as can whites that turn pale green or even blood-red.
  • The flattened flower clusters that Lacecap Hydrangeas create are made up of showy, sterile florets that radiate out from a core cluster of tiny, fertile florets. The lacecap blooms will fade much more quickly than the mopheads since the fertile florets will be pollinated, only holding their beauty for around a month.
  • Deep blues, vivid pinks, pure whites, lavender, and intense red and purple hues are just a few of the many colors available. The majority of Hydrangea macrophylla varieties have the additional allure of changing color according to the pH of the soil. These species can grow blue blooms in highly acidic soils, whereas pink flowers can grow in somewhat acidic soils. If you want your Hydrangea’s blossoms to be a different hue, you can amend the soil with aluminum sulfate to make them bluer or with lime to make them pinker.
  • Zones 6 through 9 are hardy, Bigleaf Hydrangeas prefer a thick layer of mulch all year round because they are more susceptible to cold than their relatives (shredded bark, peat or compost ). This will control weed growth, hold onto moisture, and lessen soil temperature swings.
  • Bigleaf Hydrangeas prefer sun to partial shade and do best in rich, medium-moisture soils that drain well. They can only survive full sun if the soil is continually moist.
  • No significant pest or disease problems. Keep an eye out for leaf spots, mildew, bacterial wilt, and bud blight.
  • Perfect for container and foundation plantings. grouped in a protected area or used as a decorative plant. They work well as a hedge and also make wonderful cut flowers! Perfect for gardens near the sea because of their hard, glossy leaves, which can tolerate wind and salt.
  • After flowering, Bigleaf Hydrangea stems should be trimmed by being cut down to two sound buds. In the early spring, remove weak or winter-damaged stems.

Do hydrangeas bloom when coffee grounds are present?

The abundant, globular flowers of hydrangeas (Hydrangea spp.) range in color from red to various shades of pink to white. Hydrangeas bloom with blue to lavender-blue hues in the correct soil. One approach to make soil that encourages the growth of hydrangea blooms with more odd color combinations is to use coffee grinds. Learn the steps to help your hydrangea produce blue blooms before you run to the coffee shop to pick up pounds of grounds.

What occurs if hydrangeas are not pruned?

If and when you prune is the key to happy, healthy hydrangea flowers. Of course, fertilizing and offering the ideal environment have a lot to recommend them. However, if you don’t prune properly, your efforts will be in vain. Deadheading is not the same as trimming. Pruning refers to more drastic cutting to preserve shape or remove dead growth. However, feel free to discard spent blossoms or cut fresh ones to use in arrangements.

Hydrangeas can bloom on either fresh wood or old wood, depending on the species. The wood from which they blossom determines whether and when to prune.

Old wood-blooming hydrangeas do not require pruning and benefit from it. They’ll blossom more abundantly the next season if you leave them alone. But feel free to deadhead or gently thin. Just keep in mind that while new growth may appear, it won’t bloom until the following season. In our region, four different species blossom on aged wood. Additionally, they are not limited to the hues displayed here.

Climb using suckers. On your wall or trellis, resist the desire to remove the dormant growth.

The flower heads are more conical in appearance, and the leaves are large and resemble oak leaves. It’s a pleasant surprise for a hydrangea when its leaves turn reddish-orange in the fall.

They are very comparable to lacecap types, but smaller and with more compact leaves.

Pruning should be done in late winter or early spring on hydrangeas that bloom on new wood. Trim back to two feet to prune to shape. The next season’s blossoms are produced by strong, fresh growth that is encouraged by trimming. In our region, there are two types that bloom on fresh wood. They are also not restricted to the colors displayed.

Oakleaf variants are not included in cone-shaped blooms. Keep the blooms on throughout the winter to provide interest; even dried out, they are quite lovely.

regarded as a wild kind. They often have smaller blooms and leaves than Bigleaf variants and are completely white. They enjoy full sun and can grow very tall.

Knowing whether or when to prune now will help you avoid the disappointment of a hydrangea that doesn’t blossom. Don’t forget that a robust shrub will produce more gorgeous blossoms if it has well-draining soil and good organic fertilizer. Come on in, and we’ll show you where to go to develop your green thumb.

Do hydrangeas respond well to Miracle Grow?

There is no need to buy expensive plant food. This cost-effective alternative has a 15-30-15 N-P-K composition that encourages more flowers per shrub and colorful flower heads. Including hydrangeas, this all-purpose blossom enhancer can be applied to a large selection of permanent and annual blooming plants.

It offers a variety of minerals, such as iron, copper, and boron, to complement typical dietary deficits. For the biggest, brightest blooms and healthiest plants, the water-soluble formulation should be applied every 7 to 10 days throughout the growing season.

  • Water-soluble fertilizer, type
  • Ratio of NPK: 15-30-15
  • Approximately 1.5 pounds
  • encourages most flowers to bloom more
  • Easily combines in a watering can
  • increases some plants’ size
  • Must be routinely administered and suitably diluted.

What is a hydrangea’s natural fertilizer?

For the development of their flowers, plants require phosphorus, magnesium, and other trace minerals like iron or calcium. Both household compost and animal dung are beneficial fertilizers for hydrangeas to add to the soil beneath the plant. To provide the roots with an excellent source of potassium, phosphorus, and magnesium as well as to foster the acidic environment that hydrangeas enjoy, apply a teaspoon of vinegar mixed with a quart of water.

Do you prune hydrangeas with huge leaves?

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.