Pruning Hydrangeas: A Step-By-Step Guide For Old And New Wood

To prune or not to prune? This is one of the quintessential gardening questions. Recently, I asked a top landscaper in Virginia to weigh in on the issue. “When is the best time to prune hydrangeas without cutting off next year’s flowers?” I asked. Her reply?

“Never,” she said with a laugh. “But your best shot is after they’ve bloomed.”

It turns out that knowing how and when to prune hydrangeas involves first, identifying what kind of shrubs you own. And it all starts with determining whether they flower on old or new wood.

PRUNING HYDRANGEAS THAT BLOOM ON OLD WOOD

Nikko Blue hydrangeas bloom on old wood

Old wood is quite simply, last year’s wood. Hydrangeas that bloom on old wood set their flower buds in late summer on stalks that have been on the plant since the previous year. 

Hydrangeas that bloom on old wood include the mophead, bigleaf (macrophylla), lacecap and oakleaf varieties.  

Oakleaf hydrangea is recognizable by its foliage that resembles oak leaves

In terms of pruning, these beautiful shrubs require very little. But if you must, knowing when and what to cut is key. That’s because the more old wood you take, the fewer flowers you’ll have next summer. 

Follow these three steps to maintain the health and vigor of your old wood hydrangeas:

  1. Immediately after flowering (and no later than July), prune flowering stems back to a pair of healthy buds.
  2. In late winter or early spring, prune out weak or damaged stems. Remove no more than 1/3 of the oldest stalks, taking them down to ground level.
  3. Repeat the process every summer to rejuvenate your shrubs and control their shape.

PRUNING HYDRANGEAS THAT BLOOM ON NEW WOOD

Limelight hydrangeas bloom on new wood

Hydrangeas that bloom on new wood set their flowering buds on the current season’s growth. Since their flowers come from new growth from the base of the plant, they can be pruned almost any time of year, except summer. Follow these three steps to maintain the health and vigor of these types of hydrangeas:

  1. Cut off faded blooms in late summer to improve the looks of the shrub.
  2. Prune out the oldest canes to improve vigor.
  3. Cut back the entire shrub in late winter before new growth starts to appear.

Additional tricks of the trade include leaving some of the older branches as a framework for new growth (these types of hydrangeas tend to open up and get floppy.) Many gardeners also advocate cutting the shrubs all the way back to the ground, which often produces bigger flowers.  

‘ANNABELLE’ 

Considered the crème de la crème of all the varieties that bloom on new wood, Hydrangea arborescens Annabelle is what is called a ‘smooth’ hydrangea. Smooth hydrangeas are known for their giant white blooms. They are native to the southeastern United States.

Distinctive white blooms of Hydrangea ‘Annabelle’

What makes Annabelle so special is that it not only produces enormous, pure white flowers from June to August, but it also stays compact, growing to just 3 to 5 feet tall and wide. At first glance, it can be hard to tell this cultivar apart from other white-blooming hydrangeas. However, a number of gardeners go by this golden rule:

Annabelle flowers open lime green in early summer, change to bright white mid-summer and then switch back to light green in late summer before turning tan in the fall.

More recently, an improved version of Annabelle called Incrediball has been developed. It features basketball-sized blooms and thicker, stronger stems that won’t flop over. In fact, they’re so sturdy that they’ll stay upright even in a rainstorm. 

‘Incrediball’ features 12″ flower clusters and blooms on new wood

Most professionals recommend pruning hydrangeas like Annabelle to help control for shape and to increase blooms. For this reason, many gardeners cut them back to the ground (within 6″) in late winter or early spring. Some say this encourages these varieties to produce larger flowers and sturdier stems. But others claim it weakens the plants over time, causing them to need to be staked.

I recommend taking the middle road and pruning Annabelles back to between 1 and 3 feet above the soil.

PRUNING PANICLE HYDRANGEAS

Panicle hydrangeas bloom on new wood

Panicle hydrangeas also bloom on new wood. As a result, they can be pruned in late winter or early spring before they produce new growth. Cut them to the ground or to just a few feet above the soil depending on the size plant you want to maintain. The best known of the panicle hydrangeas include PeeGee and Limelight.

THE SUNNY SIDE OF LIMELIGHT HYDRANGEAS

When they were first introduced from Holland in the early 2000’s, Limelight hydrangeas took the garden world by storm. Featuring enormous, football shaped clusters of flowers, the shrubs performed great in full sun (although for best color, they require some shade).

Limelights keep their beautiful celadon color all summer long before aging slowly to pink. In the fall, they change to shades of dusty red and burgundy. They are panicle hydrangeas and they bloom on new wood. Prune them like Annabelles.

Limelight hydrangeas bloom on new wood

ENDLESS SUMMER – THE BEST OF BOTH WORLDS  

There’s a new kind of hydrangea in town called Endless Summer and it’s rocking the hydrangea world. Introduced in 2004 by Bailey Nurseries, Endless Summer hydrangeas bloom on both old and new wood. As a result, this gives them the ability to flower repeatedly all summer. The company’s tag line is, appropriately,

Experience life in full-bloom.

Endless Summer mophead variety

As of 2018, there are three different varieties currently available. Blushing Bride produces pure white mophead flowers that mature to soft pink. Twist-n-Shout is the first re-blooming lacecap variety. And BloomStruck has vivid purple or rose-pink mophead blooms that hold their color all summer. Summer Crush (available in 2019) will feature raspberry red or neon purple blooms.

It’s easy to imagine the benefits of plants that bloom on both old and new wood. Their flowers naturally last for most of the summer. Moreover, the company says Endless Summer hydrangeas bloom 10 to 12 weeks longer than average hydrangeas. Best of all, these hydrangeas need little to no pruning.

SOME COMMONLY ASKED QUESTIONS ABOUT HYDRANGEAS

Why are my hydrangea flowers turning brown in the summer?

The main reason that hydrangea flowers turn brown is too much sun; specifically hot mid-day to afternoon sun. To prevent this problem, site your shrubs in areas where they receive direct sun either in the early morning or late afternoon. Same goes for the lacecap varieties, which tend to have a much shorter flowering span than the mopheads. Attention to watering during dry spells also helps prolong blooms.

What do I do if my hydrangeas have grown too big and floppy?

Most gardeners advise waiting until the shrubs have been in the ground for 5 years before beginning a pruning program. If you’ve got the type that blooms on new wood, prune your shrubs in late winter or early spring for shape, taking them down to between 1 and 3 feet from the ground. If you’ve got the kind that blooms on old wood, follow the method above, removing 1/3 of the oldest living stalks each summer after the shrubs have flowered.

When I cut blossoms will it hurt the other blooms?

After August, cut only short stems to avoid affecting next year’s blooms

For hydrangeas that bloom on old wood, deadheading (or cutting flowers for indoor arrangements) can be performed on long or short stems in June through July without affecting next year’s flower buds. After August, it’s best to harvest only short stems.

Can I prune some of the branches without affecting the others?

Yes. You are only cutting off the flower buds on the stalks that you prune.

Does watering keep the blooms going? Why do my hydrangeas look so dry in July?

As with all plants, watering during dry spells is key. Keep the soil moist around your hydrangea shrubs to keep the flowers going all summer.

I did all the right things and my hydrangeas didn’t bloom this year. What happened?

Weather can negatively affect blooms, too

Finally, you can follow all the rules and prune your new or old wood shrubs correctly, but weather can also have its negative effects, particularly frost. In colder regions, flowering can be adversely affected by either early fall or late spring frosts, making it confusing as to whether you pruned off the blooms yourself or left it to Mother Nature.

For photos of my garden designs, including plant lists, check out my Instagram at carole.herebydesign. I post seasonally from spring through fall.

 

Why Star Magnolia Deserves A Spot In Your Garden

When it comes to stunning, early-blooming trees, it’s hard to beat the star magnolia. Every March, it showers the landscape in a flush of bright white. For what it lacks in size, it more than makes up for in stature. I love how the blossoms hang like fallen stars from its smooth, bare branches.

THE SMALL GARDEN’S MAGNOLIA

Now, even small gardens can have a magnolia! What’s more, star magnolia is slow-growing, so it won’t overwhelm your landscape. Topping out at a manageable 10 to 15 feet, it makes an excellent specimen tree while also providing a great backdrop to any mixed shrub border. 

Yet for all that, the tree’s most valuable asset, in most people’s view, is its early spring blossoms. Typically flowering in early March, the star magnolia is lush with blooms when most other ornamentals are scarcely starting to bud. Moreover, the flowers are fragrant. Each is composed of more than a dozen ribbon-like petals. And some varieties boast as many as 30.

And while star magnolias are typically associated with white flowers, there are also a number of pink varieties. All are magnets for pollinators, which gives your other plants an early start on the season.

FOR STAR MAGNOLIAS, THE SHOW NEVER STOPS

But, for those who think star magnolias are all about spring, think again. The little trees offer fall and winter interest as well. In autumn, the foliage turns yellow, then bronze, providing an interesting complement to other fall colors.

And star magnolia’s twiggy, many-branched shape provides great winter interest. Colored a shiny, chestnut brown, the branches contrast handsomely with the tree’s smooth gray trunk, which slowly turns silver with age. As an added plus, the buds, appearing in late winter, are fat and fuzzy, just like pussy willows. 

TOP STAR MAGNOLIA VARIETIES TO TRY

Ready to give star magnolia a try? Below are some the most popular cultivars that offer reliable, low-maintenance early spring color. Deciduous magnolias are best planted when dormant, typically in late fall.

‘Centennial’ produces fragrant, waterlily-shaped blossoms in early to mid spring. The large white flowers often have a pink tinge at the base of the petals. 

Magnolia stellata ‘Centennial’

‘Jane Platt’ produces double, scented, pale pink flowers with long, narrow petals in early to mid spring.

Magnolia stellata ‘Jane Platt’

‘Royal Star’ has pale pink buds that open in early spring to pure white flowers. In particular, this cultivar is known for its almost 5-inch (12 cm) wide flowers with up to 30 petals. ‘Royal Star’ blooms later than the species. 

Magnolia stellata ‘Royal Star’

‘Rosea’ is a pink-flowered variety. It has a rounded shape and dense bushy habit. This cultivar flowers a month later than the species, or in late April. 

Magnolia stellata ‘Rosea’

HOW AND WHERE TO PLANT

Star magnolia flowers are vulnerable to damage by late spring frosts, so it’s best to plant the trees in a sheltered spot. While they’ll do fine in full sun, they’ll perform best in morning sun with filtered shade in the afternoon. Generally, the more exposed the location, the earlier the flowers open. Like most plants, star magnolias prefer moist, well-drained soil. 

Magnolia stellata really shines when viewed against a dark background. Site it in front of a stand of deep green arborvitae, a yew hedge or even a dark brick house and watch its flowers ‘pop.’  Daffodils with cream or white petals and yellow cups make excellent early-spring companions. Check out Narcissus ‘Sovereign’, Golden Echo’ or the orange-cupped ‘Barrett Browning’ for a dramatic effect.

To see photos of my garden designs, including plant lists, check out my Instagram at carole.herebydesign. I post seasonally from spring through fall.

Lespedeza: The Best Fall-Flowering Shrub You’ve Never Heard Of

lespedeza thunbergii

Lespedeza. Judging by the sound of it, you’d think it was an island off the coast of Italy. And the plant that bears its name certainly looks Mediterranean. Yet, I had never heard of this magnificent, fall-blooming shrub until a client of mine showed me a pair in her garden. Here’s why I’ve been a fan ever since. Continue reading

How To Cope With Boxwood Blight: An Expert Weighs In

It’s not every day you get to discuss your problems with an international expert. But Lynn Batdorf is the real deal. Batdorf is the world’s top resource on everything boxwood, including all of the diseases and pests that affect this diverse species. Recently he spoke to me about how to deal with the latest threat to our gardens, the dreaded boxwood blight. Continue reading

Camellias Take Center Stage At California’s Filoli Gardens

Camellia japonica 'Cheryl Lynn'

Winter can be a dreary time in the garden, especially on the East Coast. But as soon as the camellias start flowering, I am reminded that everything has its season. These beautiful plants wait until late fall to early spring to produce their spectacular multi-layered blooms. And one of the best places to view them is at Filoli in the foothills of California’s Santa Cruz Mountains. Continue reading

For the Love of Forsythia: Five Great New Varieties

Couple strolling past cascading forsythia hedge

(Updated March 2019)

My sister Cindy was born in late March. And every spring, when the forsythias bloomed, we celebrated with a family-coined phrase. My mother would say: These are for-Cynthia. My little sister would puff up with pride and it wasn’t long before she started gravitating towards the color yellow. I’ll never forget the canary carpet she insisted on having in the 70s.

Although I was secretly jealous that a flower bloomed especially for my sister, I grew to welcome the arrival of the sunny blooms. In my mind, forsythia will be forever tied to my sister, to March and the happy return of warm weather.

 

IT’S NOT THE BEST IN A MARTINI

It doesn’t taste good in tapenade either, but forsythia nevertheless belongs to the olive family, Oleaceae. Along with other showy members like lilac and jasmine, it is grown primarily for its bright, fragrant flowers. There are about 11 species, most of which are native to eastern Asia with one hailing from southeastern Europe.

Large flowering forsythia in a botanic garden

IT’S ALL ABOUT THE FLOWERS

Forsythia’s early yellow blossoms are undoubtedly the most appealing feature of this multi-branched, deciduous shrub. Developing before the leaves, they are produced in brilliant clusters on the previous year’s wood.

Forsythia buds on a bare branch

Forsythias flower on last year’s wood

Ranging in color from pale to deep yellow, each flower is composed of four elongated petals. 

Close-up of a forsythia flower

The flowers are followed by bright green foliage that turns shades of yellow or purple in the fall.

Leaves follow the blooms on a forsythia shrub

Forsythia foliage follows blooms

Best of all, barring a cold snap, forsythia flowers will last for two to three weeks. And if you can’t wait until spring, it’s easy to force them indoors

Forced forsythia blooms in a glass vase

Forsythia blooms are easy to force indoors

WHY ISN’T MY FORSYTHIA BLOOMING?

As a garden designer, I am often asked this question. The answer usually lies in when the shrub was pruned. Since forsythias produce their buds on the prior year’s growth, it’s imperative to prune them right after they flower. Otherwise, you risk cutting off the majority of next year’s blooms.

Less frequently, prolonged periods of unusually cold weather can negatively affect flowering for the coming season.

Close-up of forsythia leaves

If you prune forsythia too late, you’ll cut off next year’s blooms

Forsythias are fast-growing. When left untended, they easily become leggy. Don’t hesitate to be aggressive when pruning. (I hack mine back by a third every spring right after flowering.) The shrubs will quickly bounce back and push out new growth the following year.

WHAT ARE THE BEST VARIETIES AVAILABLE TODAY?

Most of today’s modern varieties are the result of a cross between two Chinese species, Forsythia suspensa and Forsythia viridissima. These were the first species introduced to Western gardens from the Far East. 

Forsythia suspensa, commonly called Weeping forsythia, is a popular plant all on its own and is still widely grown for its large size and pale yellow flowers. Tough and reliable, the shrub typically grows to 8- to 10-feet. Its characteristic weeping habit makes it an excellent hedging plant. It also looks great on a slope or hanging over a wall where its drooping blooms can be fully appreciated.

Forsythia suspensa

Forsythia suspensa

That being said, it is the hybrid of Forsythia suspensa and Forsythia viridissima, Forsythia x intermedia, that is behind many of the most popular cultivars today. Also known as Golden Bells, or Border forsythia, the medium-sized, upright shrub has the bright yellow flowers most commonly associated with the species. The cross has also produced many new varieties, including a number of lower-maintenance, more compact forms. 

Golden yellow Forsythia x intermedia

Golden Bells

If you’re looking to create a hedge, I recommend using the larger, deep-yellow cultivars Arnold Giant, Lynwood Gold, Karl Sax and Spectabilis. They’ll happily grow unimpeded to 8- to 10-feet or more. The dwarf varieties Arnold Dwarf and Gold Tide are two popular forms that grow to just 3 feet and are often used as groundcovers. However, in my experience, Gold Tide likes to be wider than tall. So beware if you’re combining it with other flowers.

Golden Peep and Goldilocks are small and have compact branching. They look great close up to the house or in the flower border.  They also make great container plants. The slightly larger Sunrise is a great choice if you’re looking for fall leaf color.

FORSYTHIA LIKES TO PUT DOWN ROOTS

Where its branches touch the ground, forsythia will quickly take root. This is great for mass plantings, but not so desirable in a garden. Most springs, I chop off these offspring to keep things under control.

Close-up of forsythia flower

BEST BLOOMS IN FULL SUN

For the best blooms, plant Forsythia x intermedia varieties in full sun to part shade. The shrubs need a minimum of four hours of direct, unfiltered sunlight each day to flower. Like most plants, forsythias perform best in well-drained soil.

 

How To Protect Your Evergreens From Winter Damage

cover

You could say that evergreens are the stars of cold weather, instantly infusing drab winter landscapes with color and texture. When well sited, watered and fed, most can stand up to the harshest of conditions. Still, some evergreens are less equipped than others to battle icy winds and harsh winter sun. These are the plants that can benefit from a little extra TLC to prepare them for colder temperatures. Continue reading

Boxwood Care: How To Identify And Treat 4 Common Pests and Diseases

Boxwood balls in the landscape

Boxwood has been a garden staple for centuries. Not only does it add structure to outdoor spaces, but its dense, evergreen foliage can be sheared into almost any shape imaginable. For those of us on the East Coast, the fact that deer won’t eat it only adds to its appeal. There’s just one problem: it’s plagued by a bunch of pests and diseases. Continue reading

How To Create Winter Interest In the Garden

cover 2

“I prefer winter and fall, when you feel the bone structure in the landscape – the loneliness of it – the dead feeling of winter. Something waits beneath it – the whole story doesn’t show.”

~  Andrew Wyeth

I grew up near Chadd’s Ford, Pennsylvania in the heart of the Brandywine Valley. The American painter, Andrew Wyeth, drew his inspiration from this place, beautifully capturing the winter landscape in a subdued mix of browns, whites, tans and grays. My winters were painted in the same palette, made all the more rich by the stark outlines of bare branches silhouetted against a white sky. Nature sure knew how to create a lot of winter interest. Continue reading