The big-leaf hydrangea species Hydrangea macrophylla includes varieties like Dear DoloresTM and “Big Daddy.” The two most popular varieties of hydrangeas, mopheads and lace-caps, are included in this category, which is the most varied. Big-leaf hydrangeas bloom on old wood, which means that their stems from the previous growing season are where their blossoms first appear. In the spring, pruning would eliminate the flower buds, leaving us with a plant that wouldn’t bloom that year. Big-leaf hydrangeas are instead pruned in the summer, following their flowering season. Trim the stems every season, up to one-third of them. Start by pruning at the base of the weakest shoots, both old and young. Keep several stems of the more prolific older wood, as well as healthy new stems that will bloom the following year. This kind of replacement pruning will maintain the plant’s productivity while promoting healthy growth.
Although Dear DoloresTM is a member of this family, it is a bit of an outlier because it reblooms and does so on both old and new wood. As a result, it is a little more understanding. Pruning it in the winter, spring, or summer will still result in blooms from the growth of the current season.
Does my Hydrangea macrophylla need to be pruned?
Late summer to early fall (August to September) sees the development of these plants’ bloom buds for the next year. So, before August, prune these shrubs once they are finished blooming (again, make a heading cut).
The Endless Summer is an exception. The Original Bigleaf Hydrangea (H. macrophylla ‘Bailmer’ PP15,298) as well as many cultivars from Bailey Nurseries’ Endless Summer line, including Blushing Bride, BloomStruck, Summer Crush, and Twist ‘n’ Shout.
On the wood from last year and any new wood that sprouts this year, the H. macrophylla blooms. Therefore, whether you prune it or not, it will bloom. A big, 4-foot-tall ring of hardware cloth can keep rabbits from nibbling on the stems of H. macrophylla over the winter.
The pink to blue tint of the Endless Summer hydrangea’s flowers (achievable with the right soil amendment) plus the fact that it blooms on both old and new wood caused it to make a big splash on the Minnesota landscape plant scene.
Should I prune my macrophyllous hydrangea?
To keep your hydrangeas looking their best and promote the development of new flowers, deadhead regularly during the blooming season.
But in mid- to late-fall, stop deadheading hydrangea shrubs, leaving any spent blooms in situ. This not only adds beauty to the winter landscape but also guarantees that the buds that will bloom the following spring are not removed.
How is a Hydrangea macrophylla maintained?
Some Hydrangea macrophylla species bear their flower buds through the winter because they bloom on aged wood. Frost that arrives too early or too late can harm flower buds and keep them from blooming. For instance, only three out of five years may see bloom success in Zone 5, but the plant will still thrive there. Recent arrivals, which bloom on both new growth and stems that have been in the ground for a year, are fortunately likely to blossom for gardeners in milder climates.
Light/Watering: In the North, the majority of cultivars tolerate full sun, but they thrive from afternoon shade. Plants need afternoon shade in the South. Plants should not be grown in hot, dry, exposed locations; moist soils that do not dry out are desirable. Mulch helps to stabilize soil temperatures and preserve moisture.
pH of the soil, fertilizer, and soil: Use a fertilizer intended to promote blooming once in the spring (such as 15-30-15). The pH of the soil affects the color of the flowers in many H. macrophylla species; blooms in low pH (acid soils) will be blue, whereas flowers in higher pH will be pink. Deep, bright blues typically result from a pH below 5.0, however as the pH rises, blooms can range from blue to lavender to mauve to a vivid deep pink at pH 7.0. (neutral). Aluminum availability in the soil is dependent on pH; in acidic soils, aluminum is more easily obtainable, which contributes to the blue hue of the flowers. Using a fertilizer low in phosphorus will help you grow blue blooms because this nutrient binds up aluminum in soils. If you want pink flowers but your soil is acidic, all you have to do is add lime to boost the pH and use a balanced fertilizer. If you want blue flowers, aluminum sulfate will cause the pH to decrease.
To learn more about soil testing in your area, we advise you to contact your cooperative extension service. For a list of organizations taking part in the Cooperative Extension program, see this page.
Additionally, we supply a Soil pH Meter that enables you to test your soil and yields prompt, precise results.
How is Hydrangea macrophylla pruned in the UK?
If you’re new to growing hydrangeas or an experienced grower who has encountered a pruning challenge, let us help you master this procedure with our simple-to-follow instructions.
We’ve already discussed why hydrangeas don’t bloom, but since pruning errors are the leading cause, we thought it was time to put together a comprehensive guide to pruning.
Find Out Which Hydrangea You Have
Some hydrangeas respond best to modest trimming, won’t put up with mistakes, and may even delay blooming until the following year. Others favor vigorous trimming, which, if not done properly, can leave them looking lanky and sparse.
If this sounds complicated, don’t worry; our instruction is simple to use and ensures success.
There are five main types of hydrangeas, and each requires a different pruning method:
The “large leaf variant” of hydrangeas is called hydrangea macrophylla. Lacecap, mophead, and mountain macrophylla are the three varieties.
The only hydrangea that produces leaves that resemble oak leaves but are larger is called oakleaf.
This hydrangea is distinctive and simple to recognize thanks to its paniculatalong panicles that have clusters of flowers.
This hydrangea stands out from the crowd with to its big, globe-like flowers and aborescenslarge leaves.
The only climbing hydrangea, which may grow to a height of 20 meters. It makes tiny clusters of lacecap blooms, which are often white.
The following images will assist you in recognizing your hydrangea:
How to Prune Hydrangeas
It’s crucial to be aware that some species of hydrangeas will produce blooms via buds that grew the previous year before reading our guide to pruning hydrangeas.
The hydrangea in question blooms on “Old wood has autumnal buds that, if they survive the winter frost and aren’t accidentally cut off, will develop into flowers the following summer.
The most frequent causes of hydrangeas not blooming are frost and pruning errors, so the gardener should take care not to prune the “aggressive old wood hydrangeas.
There are two ways to do this: in the spring after the first frosts, or as soon as the summer blossoms start to fade.
There are two viable times to do this: In the spring after frosts or right away after summer blooms end, before the buds for the following year have formed.
Although it doesn’t need to be pruned every year, you can remove up to 20% of the stems immediately above the crown in the spring to encourage the growth of new stems from the base, which will bloom the following year. After the last spring frosts, cut off old blossoms at the nearest set of buds. However, keep in mind that the deeper you prune a stem, the more buds you’ll eliminate and the fewer flowers that will appear. Instead, prune in the summer after the blooms have faded and before the plant begins to form buds for the following year.
frequently needs less pruning. To the nearest healthy group of buds, trim old blossoms. If necessary, cut up to 20% of the old stems slightly above the ground to promote new growth.
Either prune the entire shrub back to the framework (the thickest stems), leaving a few buds on the stems, or chop back the previous year’s growth, leaving two to three sets of buds. A framework of thicker stems should be left after trimming off between 30 and 50 percent of the plant and all slim or weak stems.
If you want to encourage more but smaller blooms, prune softly to a framework 50 cm from the ground. If you want to encourage fewer but larger blooms, prune severely at 25 cm.
After the blossoms have faded and before new buds grow in the summer, prune. Trim stems that are too long and straying to the required length or to the nearest major stem or branch.
A stem that has been cut down by more than half won’t likely bloom this season, but it will the next year. Or it could produce tiny blossoms that are rounded off by leaves on longer, more recent branches. Alternately, prune after the summer blooms fade and before the plant forms buds for the next year. Be mindful that some regions offer winter protection from frost through the old, faded blossoms, which is why some gardeners keep them on all winter. It won’t blossom the next season if the buds are removed or harmed by frost.
can withstand pruning that is more vigorous. Light pruning will result in more panicles, but they will be visibly smaller.
Consider twice-yearly pruning to gradually bring a huge, unruly climber under control while still leaving at least some buds for blooming.
When to Prune Hydrangea Macrophylla
The shrub that causes gardeners the greatest trouble is Hydrangea macrophylla because it blooms on old wood and is susceptible to frost.
There are various schools of thought regarding the best ways to prune macrophyllas, but it’s important to keep in mind that most macrophyllas don’t necessarily require pruning.
1) Prune as soon as the summer blossoms start to fade and before the plant begins to form buds for the following year’s flowers. If the old blossoms were left on the plant over the winter, they would provide frost protection, but this alternative eliminates that. The plant hasn’t yet set any buds, so the gardener is less likely to cut them off.
2) After the last frost in the spring, prune softly. The plant will have some frost protection if the old blossoms are left on over the winter, but harsh trimming will eliminate the buds that were formed the previous year, so no flowers will grow. Deadheading and extremely light pruning are better suited for this technique. It’s possible that if you prune vigorously in the spring, you’ll remove the majority of the buds necessary for the blooms. Deadheading, cutting off frost-damaged stem ends, and clipping out thin, weak stems are all examples of light pruning.
3) Repeat steps one through two, but cut 10 to 30 percent of the stems from the plant’s crown. This technique is excellent for shrinking a huge, stray hydrangea since it will still produce new stems from the base that will flower the following year and increase density while continuing to bloom on the surviving stalks. The hydrangea should be grown using this technique for a few years until it reaches the appropriate size.
4) In the spring, cut off all of the stems that are at or just above the plant’s crown. This procedure will result in no blooms until the next year because macrophyllas won’t flower on new growth this year, but it is the easiest way to control a giant, unruly hydrangea.
Note: After the blooms have faded in the summer, climber hydrangeas should be clipped.
Our Advice on When to Prune Hydrangea Macrophylla
You should leave the old blooms on for frost protection over the winter and softly prune in the spring after the last frosts if you want to very lightly prune your hydrangea macrophylla, which includes deadheading and removing thin, weak stems, among other things.
Want to more aggressively prune your macrophylla? Do this in the summer after the flowers have faded before the new buds form.
Want to trim back an out-of-control, overgrown macrophylla while still ensuring some blooms? To promote new growth, prune 10–30% of the stems close to the base. The old stems will continue to produce blooms. Over a few years, repeat the procedure.
How is a Hydrangea macrophylla UK cared for?
Keep hydrangeas regularly watered during summer heat waves since they thrive in moist soil and have a propensity to wilt in hot temperatures. In order to keep hydrangeas blue, irrigate with rainwater.
Every spring, use leaf mold, compost, or well-rotted manure to mulch hydrangeas. They don’t require feeding because doing so promotes the growth of leaves at the expense of blossoms.
By fertilizing with a fertilizer strong in potassium and low in phosphorus, lacecap, mophead, and Hydrangea serrata can transform their pink blossoms to blue ones. To keep the blossoms blue, you may also grow your plant in a pot of peat-free ericaceous compost and water it with rainwater.
It’s more difficult to turn pink hydrangea flowers from blue ones. By adding dolomitic lime, the pH must be raised. In the first year of growth, it’s not uncommon for a plant to produce several different colored flowers on a single plant. Although few gardeners attempt to alter flower color, it’s fascinating to understand the reasons why plants can differ.
How to prune hydrangeas
Lacecap and mophead hydrangeas, Hydrangea macrophylla, and Hydrangea serrata
Midway through the spring, prune. Don’t cut them back severely because they produce their blossoms on old wood, otherwise you’ll miss out on this summer’s blooms. The old blossoms are typically left on over the winter because they protect the fresh growth underneath. Just above the top row of hefty buds growing beneath the dead flower head, trim the flower head back to its original position. The fresh flowers will grow in this location. Cut part of the stems off near the base of an overgrown plant.
Hydrangea aborescens and Hydrangea paniculata
In the early spring, trim back. Although pruning is not necessary, if it is not done the plant will grow taller with the majority of its flowers at the top. These two varieties of hydrangea bloom on fresh wood, so you can prune them more severely without losing this season’s blooms. Depending on how tall you want your plant to be, prune last year’s growth back to a sturdy structure that is between 30cm and 60cm high. On each stem, prune to just above a pair of sound buds.
Hydrangea quercifolia and Hydrangea aspera:
in the spring, lightly prune
Simply cut off any outdated or crossed stems and flower heads.
Hydrangea petiolaris, which climbs:
For optimal results, prune in the summer after flowering. Trim the floral branches back to a pair of fresh blooms.