Hydrangeas are traditional garden shrubs with striking foliage and long-lasting clusters of flowers that bloom from mid-summer to fall in hues of white, pink, red, and blue.
All species favor soil that is humus-rich and well-drained. Additionally, none of them are especially drought tolerant. Even after becoming established, they value deep irrigation, particularly in the summer. Hydrangeas BIGLEAF, CLIMBING, and ASPERA appreciate partial shade because afternoon sun dehydration is a problem for them on hot days. After becoming established, hydrangeas such as SMOOTH, PANICLE, and OAKLEAF tolerate full sun.
BIGLEAF HYDRANGEAS – H. macrophylla and H. serrata …are typically divided into two types:
- MOPHEADS feature large, spherical heads made up of dense clusters of petals. LACECAPS have a flatter, more disk-like appearance due to the presence of a vibrant ring of petals encircling a central cluster of smaller, fruitful flowers. Lacecap Hydrangea serrata species predominate. Both forms develop as circular mounds that range in height and width from 4 to 7 feet. Frequently, dwarf forms are offered.
Pruning
Pruning is not necessary for hydrangeas. When the flowers begin to wilt, we advise deadheading them. For older plants, we advise light rejuvenation trimming. Studies have demonstrated that pruning hurts floral exhibits. Pruning may result in larger flowers being produced the following year, but there will be far less of them than if the plant had never been pruned. It is preferable to get a dwarf variety if a short-stemmed plant is wanted rather than creating a situation where you would need to regularly prune a large-growing type. However, older plants could gain from modest rejuvenation trimming. Just after the Bigleaf Hydrangea’s late summer flowers, prune it. The flower buds for the following year may be removed if pruning is put off too late after flowering, leaving the plant insufficient time to produce new flower buds.
Eliminate any branches that are dead, broken, infected, or crossing. After that, thin the plant by chopping off the oldest (woody) branches and returning them to the ground or the main trunk. A branch tends to blossom more the more it is exposed to light.
Changing Flower Color
Despite the fact that Bigleaf cultivars are bred to have a particular color, that color can be slightly changed by adding particular nutrients to the soil before planting and each fall or spring, well before bloom season. Add aluminum sulphate (marketed as “blue” for blue hues) “Add dolomite lime to the blueing recipe (which can be used year-round) for pinks and reds. Do not combine pink hydrangeas with plants that thrive in acidic soil, such as rhododendrons, azaleas, and berries. Because tap water is frequently mildly alkaline, it may cause flowers, especially those in pots, to turn more pink. Some kinds are impervious to color alterations.
HYDRANGEA PANICLE – Hydrangea paniculata The upright Hydrangea is called a panicle. They may be instructed in “if desired, tree forms. Huge cone-shaped flower clusters that start off white and progressively become pink, drying out frequently and sticking to the bushes for months, are shown in profusion. They normally reach heights of 8 to 12 feet without pruning. Pruning typically involves thinning or heading back robust stems in late winter or early spring and removing wasted flower clusters in the fall if they are unsightly.
AKA Hydrangea quercifolia, OAKLEAF HYDRANGEA These have striking, oak-shaped leaves that are bigger in areas with more shade and turn a gorgeous bronze or scarlet in the fall (better color in sunnier locations). The flowers are a 10-inch-long cluster that start off white and turn pink as they age. Can grow to a height of around 6 feet. Pruning Oakleaf blooms on growth from the previous year. In the late summer, prune. In order to give the plant enough time to form bloom buds for the following year, if you need to prune a significant portion of it, do so as early in the summer as you can.
Hydrangea arborescens, often known as smooth hydrangea With the exception of “Annabelle,” which grows only 4-6 feet, these produce enormous white blossoms on dense, tall stalks up to 10 feet high. Pruning typically involves thinning or heading back robust stems in late winter or early spring and removing wasted flower clusters in the fall if they are unsightly. If needed, they can be severely trimmed.
HYDRANGEA ASPERA LACECAP – Hydrangea aspera These have flowers that resemble lacecaps but with blue centers encircled by rings of white or pink blossoms instead of the other way around. Some cultivars have enormous, fluffy leaves that resemble tropical foliage. Compared to bigleaf variants, these hydrangeas are taller and wispier. They often reach heights of 8 to 12 feet and widths of 6 feet. Pruning Other than removing dead or broken wood, these plants have a lovely natural shape, thus pruning them is typically not essential. H aspera blossom on old wood, so you can, if you’d like, prune after the late summer flowering period.
HYDRANGEA – CLIMBING Hydrangea anomala petiolaris A nice woody vine with midsummer flowers that clings to brick, masonry, or wood with aerial roots. The cream-colored, lacy, and delicate blooms as well as the flaky bark are also appealing in the winter. Pruning is not necessary at all or may only be needed to thin or direct growth. Reduce the length of particular shoots in the summer if they have grown too far.
Drying Flowers
For winter enjoyment, hydrangeas make lovely dried flowers. select mature flowers (whose center sepals are fully open). Like other cut flowers, remove the leaves and submerge the stems in water. Removing the flowers from the water after they resemble paper will allow you to utilize them in dry arrangements.
When should hydrangeas be pruned?
Depending on which group the plant belongs to, the timing and extent of pruning are determined:
Advice on Pruning for Group 1:
- As the days get shorter and the weather gets colder in the late summer and fall, buds for the following year’s blooms start to form.
- Typically, removing dead, diseased, or damaged branches is all that is required to preserve shape, size, and a healthy plant. Otherwise, gentle pruning ought to be practiced.
- In the summer, trimming should begin as soon as flowering ends, but no later than August 1. Pruning should not be done in the fall, winter, or spring because you risk removing fresh buds.
- Tip-pruning the branches in the spring as the leaves begin to appear can promote more numerous, smaller flower heads as opposed to fewer, larger flower heads.
Advice on Pruning for Group 2:
- On the growth of the current year, flower buds form.
- Early in the spring, as the leaves are starting to emerge, prune.
- Just above a node, prune branches back by half to a third.
- After that, prune any fragile or spindly branches.
- Minimal trimming encourages huge, strong bushes with many of tiny flower heads in H. arborescens. Hard pruning between 12 and 18 inches from the ground, or even all the way down, will result in fewer but larger flower heads that may flop if unsupported.
- For H. paniculata, remove the surrounding smaller wood while leaving the larger stems in order to establish a sturdy foundation.
Pruning may be connected to flower head size. Shoots will grow more vigorously and flower heads will be bigger and fewer with more rigorous trimming. Smaller but more numerous flower heads may result from less aggressive or tip pruning.
Consideration of hydrangeas’ mature size is the best piece of advise. Place them in a location where they won’t outgrow and won’t need a lot of pruning to keep them in check. Hydrangeas don’t need to be pruned precisely or often; as long as dead wood is removed, they will remain healthy and continue to develop and bloom.
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.
Before winter, should I trim back my hydrangeas?
It’s not necessarily necessary to severely prune your hydrangeas (Hydrangea spp.) before putting them to bed for the winter. Depending on the cultivar, hydrangeas can be grown in USDA plant hardiness zones 3 through 9, with each variation having different pruning requirements. Before you grab the shears, you must identify the type of hydrangea to know how far back to cut it for the winter.
Tip
Depending on the variety, hydrangeas can bloom on either old or new wood. Old-wood blooming hydrangeas need to be pruned just after the flowers fade in the late summer, whereas new-wood blooming hydrangeas should be pruned in late winter before new growth begins.
Should hydrangeas be pruned annually?
Only prune these hydrangeas in the summer after bloom, not in the fall. In August and September, old wood hydrangeas begin to form their bloom buds for the following year. It is advisable to delay pruning your hydrangeas until the following year if you don’t do it right away. If not, there won’t be any blossoms the next spring.
Cut back these shrubs in late winter before new growth begins
Shrubs that flower on young wood typically start blooming later than old-growth bloomers, beginning in June and continuing until the first frost, because they need to grow and set buds the same year that they bloom. As long as you avoid trimming when the flower buds are opening, these shrubs are understanding if it is not done at a specific period.
1. Trim the flowers all the way back for larger blooms.
These bushes can be completely removed from the ground in late winter or the beginning of spring. If cut severely like this every year, smooth hydrangeas will produce much larger flowers, but many gardeners prefer smaller blooms on stronger stems.
2. Maintain an old growth foundation to lessen flopping
Especially after watering from above or after a heavy storm, the branches of some hydrangeas frequently topple over from the weight of their blooms. Cutting the stems to a height of 18 to 24 inches will help to reduce this flopping by creating a strong framework for fresh growth.
Janet Carson is the University of Arkansas Cooperative Extension Service’s horticulture specialist.
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Should I remove the brown blooms on my hydrangea?
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.
Do you prune hydrangeas in the spring or the fall?
Pruning is not typically thought of as one of the many gardening activities that may be done in the fall, despite the fact that there are several. It can be difficult to cultivate hydrangeas successfully in New Hampshire, and if you want your plants to blossom, there is frequently very little room for error in pruning.
Wait until Spring to prune hydrangeas
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. In any case, it is better to postpone all hydrangea pruning until spring. Hydrangeas, as with all other trees and shrubs, go dormant in the fall. Not much new growth is produced by them until the next spring. As new growth is more vulnerable to harsh cold at the location of wounds, plants that have been trimmed now run a higher risk of winter damage. Additionally, fall pruning may lessen the quantity of June blooms.
Considerations for pruning hydrangea species commonly grown in New Hampshire gardens
The large blue mopheads or lacecaps known as bigleaf hydrangeas (Hydrangea macrophylla), which are familiar to most gardeners, form their flower heads at the tips of stems on old wood from the previous year. 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.
The three other hydrangea species that are frequently planted in Fresh Hampshire—oakleaf (H. quercifolia), panicle (H. paniculata), and smooth—all bloom on new growth. Before the emergence of the leaves in the late winter and early spring, remove wasted flowers and prune the plant to improve its general structure and habit.
In conclusion, there are a ton of other activities you can engage in to stay occupied in the garden during fall. Save the spring for hydrangea pruning.