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.

 

Daylily Care: How To Extend The Blooming Season

Daylilies are called daylilies for a reason. Each flower lasts for just one day. But that doesn’t mean you can’t enjoy more blooms, more often. All it takes is a little gardening know-how, and you can trick your plant into extending its blooming season.

DONE IN A DAY

One of the most versatile and hardiest of perennials, daylilies (Hemerocallis) are a highlight of the summer garden. Although individual flowers come and go daily, plants can keep on producing new ones for up to four to five weeks. Traditionally, daylilies bloom from late June through July. But there are now many re-blooming varieties that make a second appearance in late summer, dramatically extending the growing season.

In fact, nowadays there are thousands of daylily varieties available in every conceivable size, shape and color. And most are proliferous. A single stem can produce many flowers. And an established clump can produce hundreds of blooms over the course of one summer month.

Still, easy-to-grow doesn’t necessarily mean maintenance-free. Left unattended, daylilies can quickly accumulate large numbers of spent, soggy blooms. Not only are these dead flowers an eyesore, but they can have a direct impact on blooming. Here’s why.

HOW DEADHEADING EXTENDS THE BLOOMING SEASON

It’s common knowledge that regular deadheading encourages plants to produce more flowers. But did you know that it can also extend their blooming season? To keep my daylilies blooming longer, I remove the spent flowers every morning by snapping them off at the base. There are two important reasons for why I do this:

1. It makes the plant look better. 

2. If I remove the dead flowers (in particular, the ovary/seed pods), it will send energy to the plant to produce more stalks with more flowers.

Spent daylily blooms

BEWARE OF THE DAYLILY SEED POD

Daylily flowers form near the tip of the stalk during their active growing season. But as each flower withers and drops, it leaves an ovary to develop into a seed pod. Immature seed pods look a lot like emerging blossoms. Located at the base of the flower, they are oval in shape and pale green in color.

Notice below (center) where I snapped off a flower, leaving the ovary exposed. This will develop into a seed pod.

Left alone, seed pods slowly develop alongside emerging blooms. As they ripen, they develop three distinct lobes that eventually grow to around 1 to 2 inches. 

All told, it takes about 50 days for the seed pods to finally harden and dry out. Then, at the end of the season, the pods split open at the seams to release a bunch of black seeds. This explains why you’ll often find daylilies growing in odd places, far from where you may have planted them.

Below is an immature seed pod I picked recently exhibiting just a few seeds.

A daylily seedpod and seeds

WHY REMOVING SEEDS EXTENDS THE BLOOMING SEASON

Of course, if you are planning to grow more daylilies, seed pods are a good thing. I suggest leaving a few on the plant. But if you’re interested in extending the blooming season, it’s important to remove them. Why? Because, if the plant is spending its energy forming seeds, there is little left to produce flowers. Removing seed pods not only conserves energy, but it also redirects the plant to produce more flowers.

So, when snapping off the spent daylily, make sure to remove the entire flower at its base, including the developing seed pod. Then, once the stalk is done flowering, cut it to the ground. It won’t be producing any more blooms this year.

Cut spent stalks to the ground – they’re done for the season

DAYLILIES LIKE EXTRA FOOD AND WATER

And don’t forget to feed your daylilies! A spring and fall feeding can also have a positive impact on blooming while strengthening plants for the winter. And while most daylilies are relatively drought tolerant, the more water you give them, the better the blooms. One has only to look at the moisture-packed flower itself as proof.

Are your daylilies getting large and out-of-hand? Here are some tips on how to divide them.

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

Top Red, White and Blue Flowers For The Summer Garden

For many Americans, Fourth of July is synonymous with fireworks. But for gardeners, the pyrotechnics start early. That’s because by mid June, spring pastels are already giving way to dazzling color as red, white and blue flowers begin lighting up the summer garden.

RED FLOWERS EXCITE

On the color spectrum, red is the most attention-grabbing of colors. In China, it symbolizes prosperity and good luck, while on Wall Street ‘in the red’ means you’re losing money. And on the American flag, the red stripes represent ‘hardiness and valor.’

Hybrid tea rose

In the summer garden, red flowers make a dazzling display, especially when framed by red’s complementary color, green. Looking for drama? Try grouping red flowers in front of an evergreen hedge and watch the fireworks begin!

red roses and green hedge

Red roses and green hedge

 Or, combine them with other hot colors for an eye-catching composition. 

Too many red flowers? You can cool things down by pairing them with silver. 

red salvia and silver ragwort

Red salvia and silver ragwort

And just like the stripes on the flag, white flowers offer a crisp contrast to all shades of red.

Here are some of the best red flowers for your summer garden. 

Red-Flowering Shrubs

Quince ‘Double Take ‘Scarlet’

Crimson bottlebrush, Callistemon citrinus

Stewartstonian azalea

‘Mister Lincoln’ Hybrid Tea Rose

Red-Flowering Perennials

Begonia ‘Dragon’s Blood’

Geranium ‘Americana Red’

Dahlia ‘Bishop of llandaff’

Daylily ‘Always Afternoon’

Asiatic lily (red)

Gaillardia ‘Spin Top Orange Halo’

WHITE FLOWERS BRIGHTEN

The purest of all colors in terms of composition, white is considered by most cultures to represent goodness and light. It can also indicate cleanliness and perfection. On the American flag, the white stripes signify purity and innocence.

White hydrangea

In the summer garden, white flowers add an unblemished quality to the mix. Since white reflects light, white flowers instantly brighten key areas of the garden. They also help highlight other colors. 

Below, Echinacea ‘White Swan’ enlivens a mixed border.

Drift of white echinacea

Some gardeners even go all out and create an all-white garden. (The great thing about white flowers, by the way, is that they look especially good at night.)

Garden composed of all white flowers and silver foliage.

Here are some of the best and brightest white flowers for the summer garden:

White-Flowering Shrubs

Hydrangea arborescens ‘Annabelle’

Mock Orange ‘Snow White Sensation’

Azalea ‘Delaware Valley White’

Rose ‘Boule de Neige’

White-Flowering Perennials

Phlox paniculata ‘David’

Iris germanica ‘Immortality’

Allium ‘Mount Everest’

Echinacea ‘Pow Wow White’

Anemone ‘Honorine Jobert’

Physostegia virginiana ‘Crystal Peak White’

BLUE FLOWERS CALM

Located at the other end of the color spectrum from red, blue is considered the hardest color to see. For this reason, it is known as a cool color. On the American flag, blue is the color of the Chief. It signifies vigilance, perseverance and justice.

Himalayan blue poppy

The thing about blue is that it appears to recede (notice how the blue section of the flag seems less intense than the red.) Because of this quality, blue flowers can add depth and volume to a garden composition. The only problem with blue flowers is that there aren’t many that are truly blue. Most are tinged with lavender or purple. However, color can be subjective, so people have different opinions on what’s blue.

Here are the truest blue flowers I’ve found to date for the summer garden:

Blue-Flowering Shrubs

Hydrangea macrophylla ‘Nikko Blue’

‘Bluebird’ lacecap hydrangea

Caryopteris ‘Longwood Blue’

Blue-Flowering Perennials

Blue coleus, also know as bush coleus

Gentian Sage, Salvia patens 

Lewis flax, Linum lewisii

Blue Daisy

Muscari aucheri ‘Blue Magic’

Mostly blue with lavender tinge

Hidcote Blue English Lavender

Veronica spicata ‘Royal Candles’

Russian sage, Perovskia

Catmint, Nepeta

Wishing you all a very Happy Fourth of July! 

 

 

How To Build The Perfect Monarch Butterfly Garden

monarch on pink flowers

Daniel Potter freely admits he’s not an expert on monarchs. But as Professor of Entomology at the University of Kentucky, he and his grad students sure love to run experiments. Recently, they completed a two-year study on the likes and dislikes of the popular orange and black butterfly. Now for the first time ever, there’s a roadmap for building the perfect monarch garden.

WHY WE CARE

If you’re reading this post, you’re probably already a monarch fan. The butterflies’ annual migration from Mexico to Canada is one of the most spectacular events worldwide. All told, the tiny insects fly upwards of 2000 miles roundtrip each spring, stopping four times to breed and lay their eggs. They are the only butterfly species to make such a long, two-way migration.

monarch migration

Over the past 25 years, however, there’s been a sharp decline in monarch populations. Part of this is due to a loss of habitat at the butterflies’ overwintering site in Mexico. Activities such as logging, agriculture and urbanization have all taken their toll on the central highland forests that play host to the insects six months out of every year.

But by far the most significant factor driving the decline is the dwindling supply of a plant called milkweed. The native wildflower is the only plant that monarch caterpillars will eat. And without it, the butterflies cannot complete their life cycle, sustain their migration and ultimately, perpetuate their species.

monarch feeding on milkweed

MONARCH BUTTERFLY GARDENS NEED MILKWEED 

According to the North American Monarch Conservation Plan, we need 1.8 billion milkweed stems to replace those that have been lost to agriculture and urbanization. And these contributions need to come from all land sectors in order to sustain the annual migration. This includes farms, roadsides, schools, zoos, rights of way and yes, suburban and urban gardens located along the butterflies’ migratory corridor.

Luckily, an initiative called the Monarch Waystation Program is starting to make a crucial difference. Established in 2005, it engages citizens in conservation by providing instruction and materials on how to create habitats for monarchs. The guidelines are simple – Plant two or more milkweed species for the caterpillars, some nectar sources for the adults and you become part of a national registry. To date, over 6000 Monarch Waystations in 46 states have become part of the effort. 

WHAT MONARCHS LIKE

And as it happened, the Waystation Program Registry provided the perfect jumping off point for Potter’s research into monarch butterfly gardens. A quick Google Earth search by his team revealed hundreds of habitats scattered along the butterflies’ northward route. What’s more, they represented every kind of landscape.

As Potter put it, ‘Some were non-structured, others ‘wild’, and still others were surrounded by hardscape or located in open rural areas.’ Below are some aerial shots of a few of them. (Photo courtesy Dr. Daniel Potter.)

What Potter and his team wondered was this – with all of this diversity, could there be certain habitats that were more appealing than others? To discover the answer, the group decided to survey 22 citizen-planted Waystations. Below are some key outcomes from their findings. 

1. MONARCHS LIKE STRUCTURE

Like most species, monarchs use visual cues to zero in on what they’re looking for. And in the butterflies’ case, these ‘search images’ are made up exclusively of milkweed. But as the Registry revealed, not all waystations were the same. Did monarchs favor certain monarch butterfly gardens over others?

Monarchs from ‘search images’ for milkweed

To find out, the researchers counted larvae and caterpillars for a year in their target Waystations to see if the type of habitat made any measurable difference.

monarch caterpillar on milkweed leaf

Monarch caterpillar on milkweed leaf

And they discovered that yes, the butterflies had a strong preference. A structured garden, with milkweed set off by mulch, attracted three to five times more monarchs.

The takeaway? If you want more monarchs, make it easy for them to find the milkweed to lay their eggs on. Plant it apart from other plants. Even better, surround it with a mulch circle. But make sure to provide other nectar producing plants nearby for the returning adult butterflies to feed on.

2. MONARCHS PREFER A NORTH-SOUTH ACCESS

Interestingly, the researchers found that gardens with unimpeded north-south access recruited more monarchs. This makes sense since it coincides with the butterflies’ migratory route.

monarch migration map

Monarchs prefer gardens with a north-south access

3. THE TALLER THE BETTER

While all milkweed species are suitable for food, not all are equally favored by monarchs. To find the answer why, the group compared 8 species of milkweed all grown in Kentucky and native to the area. They evaluated them as to their suitability for egg-laying as well as their usability as food for monarch caterpillars. And there was a clear preference.

Where they had a choice, monarchs preferred the taller varieties, Swamp, Common and Showy over the smaller varieties like Butterfly weed

The takeaway? If you want to attract more egg-laying monarchs to your monarch butterfly garden, plant the tall, broadleaf milkweed species.

4. MILKWEED CULTIVARS ARE EQUALLY TASTY

But what about all of the new milkweed cultivars, you ask? As it has grown in popularity (mainly due to monarchs), milkweed now comes in many cultivars boasting unusual colors and sizes.

Asclepias Gay Butterflies Mix/White Flower Farm

Not to worry. Potter and his students discovered that monarchs find these cultivars just as attractive as the straight species. But again, go with the bigger varieties if you want more monarchs.

5. DON’T LET YOUR MONARCH BUTTERFLY GARDEN BECOME AN ECOLOGICAL TRAP

Finally, there’s the case of tropical milkweed, a non-native plant that has exploded in popularity over the past decade. Both gardeners and monarchs love it. But buyer beware. Tropical milkweed is not ‘bad’, per se, but when planted in warm areas of the U.S. it encourages monarchs to stick around longer and even enables them to winter-breed.

tropical milkweed

Tropical milkweed, Asclepias curassavica

Research shows, however, that monarchs breeding on tropical milkweed throughout the winter (rather than returning to Mexico) have higher levels of protozoan infection compared to monarchs in the normal migratory cycles. It turns out that migration is key to outrunning these pathogens.

The takeaway? Stick to the tried and true native milkweed species in your monarch butterfly garden and help the insects keep to their schedule.

To learn more about Daniel Potter and his research into monarchs and other insects, click here for the Dr. Daniel A. Potter Laboratory.

This article was update January 2021.

Top Annuals for the All-Season Cutting Garden

Annuals for the cutting garden/Photo: Julie Hove Anderson Photography

As a landscape designer, I’m well versed in perennials and the kind of annuals you buy from a nursery. But when it comes to growing annuals from seeds, my experience lies mainly with zinnias. So recently, I was delighted to attend a webinar hosted by ButterBee Farm owner Laura Beth Resnick on the top annuals she grows for her cutting gardens. Continue reading

Identify Plants In A Snap With These 6 Top Apps

 What's That Flower app

Now that we’re all spending more time at home, it doesn’t hurt to know what’s blooming. And finding the answer is easier than ever with one of the dozens of plant identification apps available. But which ones work best and provide the fastest, most reliable material? I decided to do a comparison. Continue reading

Finally, A ‘Phenomenal’ Lavender That Looks Good All Winter

They said it couldn’t be done, but finally, there’s a new kind of lavender that looks good all winter. Appropriately dubbed ‘Phenomenal’, it’s so good, in fact, that it’s now being used for municipal plantings. To understand the hype, I bought three plants last year to carry out a trial run. What I discovered was nothing short of, well, phenomenal. Continue reading

Meet Stevia Rebaudiana: The Plant Behind the Hype

stevia rebaudiana

Stevia rebaudiana

Last week, I was vacationing in Canada when an interesting commercial popped up on the television. It was an ad for the sweetener, stevia, and it featured enthusiastic users growing plants at home. Needless to say, it caught my attention. I had heard that stevia extract came from a ‘natural’ source. But I’d never stopped to consider what that meant from a gardening perspective.

I decided to dig deeper. Continue reading

Chesapeake Bay Wildflowers: July’s Top 10 Bloomers

IMG_0118

‘There are always flowers for those who want to see them’ – Henri Matisse

For most of my life, I’ve been more attracted to ornamentals than to wildflowers. Even though I’ve noticed many beautiful species in the landscape, I’ve never really taken the time to observe them. You might say, I’ve been wildflower blind. Continue reading