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Pruning Shrubs, Part 4 - A Plant by Plant Guide

Learn specifics for pruning some common shrubs.

Pruning Demystified - Download PDF

Contributors: Stacey Hirvela

Here, we’ll put the principles of the why, when, and how to prune in context for specific shrubs. Remember, it is not necessary to prune plants every year – in fact, we select our shrubs specifically to be low-maintenance and easy to grow. Before you put the instructions below into action, go back and read part one of our pruning series to determine if you need to prune in the first place. When in doubt, don’t prune!

Hydrangeas

We’ll start with hydrangeas since they are the most often asked about shrub when it comes to pruning. Three main types of hydrangeas are commonly found in our gardens; none of them require annual pruning to perform well. However, if you’ve decided that your hydrangeas need pruning, it is important to know which type you have to make the right decisions about when and how to get the job done.

Bigleaf hydrangea, known botanically as Hydrangea macrophylla, is sometimes also called mophead hydrangea, lacecap hydrangea, florist’s hydrangea, or hortensia. It is a popular gift plant as well as a landscape plant, with big, round flowers in pink, purple, or blue.  Bigleaf hydrangea is the plant that throws a wrench into all of the conventional wisdom and advice about pruning, because it flowers in late summer on old wood. It is the only popular landscape plant to do this, which makes it especially tricky to prune.

The best advice on pruning big-leaf hydrangea is to avoid doing so if at all possible, because you cannot prune it without sacrificing some flowers. If you prune before it blooms, you remove flower buds. If you prune after it blooms, it won’t have enough time to grow the mature wood that is capable of producing flower buds for the following year. Even in the case of reblooming hydrangeas like the Let’s Dance series, which flower on both old and new wood, avoiding pruning ensures the longest display and showiest performance. We select all of our big-leaf hydrangeas for a nice, rounded, compact form, so they don’t require pruning to look handsome and tidy, though any remaining flowers from the previous year should be removed when new growth begins in the spring. If you’ve inherited an older type of hydrangea, or moved to a home with a large, unruly hydrangea, the best management strategy is to shorten one-third of the stems every year after flowering. In this way, two-thirds of the plant remains to flower every summer and the plant can be maintained at a lower height.

Oak leaf hydrangeas and climbing hydrangeas, which are not as widely grown as big leaf hydrangeas, also flower on old wood and shouldn’t be pruned if possible. If, however, they must be, follow the guidelines above for big-leaf hydrangea.

The other two popular types of hydrangeas – smooth hydrangea (Hydrangea arborescens sometimes called ‘Annabelle’ hydrangea) and panicle hydrangea (Hydrangea paniculata – also known as peegee hydrangea) – flower on new wood, so can be pruned and still flower that same summer. It’s a good idea to go out in early spring and remove any skeletons from last year’s blooms that are still on the plant, as these may not fall off naturally and can spoil the look of this year’s flowers. Aside from that recommendation, these plants do not strictly require regular pruning, though if do you do want to prune them, they will still flower if that summer. One-third of their height may be removed each spring to encourage new growth and branching if desired.

 

 

 

 

The following plants may be pruned in early spring, just as the new growth begins to emerge on the stems:

Abelia
Butterfly Bush (Buddleia)
Beauty Berry (Callicarpa)
Bluebeard (Caryopteris)
Summersweet (Clethra)
Burning Bush (Euonymus)
Rose of Sharon (Hibiscus)
St. John’s wort (Hypericum)
Goji berry (Lycium)
Potentilla
Rose  

 

 

 

The following plants may be pruned later in the season, immediately after they finish flowering:

Carolina allspice (Calycanthus)
Quince (Chaenomeles)
Red twig dogwood (Cornus)
Deutzia
Pearlbush (Exochorda)
Forsythia
Sweetspire (Itea)
Beautybush (Kolkwitzia)
Ninebark (Physocarpus)
Rhododendrons and azaleas
Elderberry
(Sambucus) *note – if growing for fruit, elderberry cannot be pruned without sacrificing flowers/berries
Spiraea
Lilac (Syringa)
Weigela 

Shrubs that flower on old wood and offer ornamental fruit cannot be pruned without sacrificing their display, so it is best to avoid pruning these all together:

Winterberry holly (Ilex verticillata)
Blue holly (Ilex x meservae)
Viburnums  - if grown for the berry display – varieties grown only for their flowers, like Koreanspice viburnum, may be pruned immediately after flowering if necessary
Coralberry (Symphoricarpos)

Conifers and evergreens that are not grown for their flowers or fruit should generally be pruned in late spring or early summer, after new growth has already begun but before temperatures get too warm.

 

This group includes:

Boxwood
Wintercreeper (Euonymus)
Bay laurus
Japanese holly
False cypress (Chamaecyparis)
Juniper
Arborvitae (Thuja)
Russian cypress (Microbiota)

Remember – when in doubt, don’t prune! It’s easier to correct an unpruned shrub than an incorrectly pruned shrub. If you still have questions, we’re always here to help. Contact us any time!

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Anonymous's picture
Anonymous Mon, 08/01/2016 - 2:08am

I just moved to Bel Air Maryland and the property were my home is located on has so many different shrubs, i don't know how to care for them. Please give me some resource information if possible.

Stacey Hirvela's picture
Stacey Hirvela Tue, 08/09/2016 - 1:21pm

Can you contact us here: https://www.provenwinners.com/feedback and we'll let you know how to send us some photos so we can give you the best advice.

Anonymous's picture
Anonymous Mon, 08/03/2015 - 7:09am

Do you have any suggestions on how to support this plant? The main stem is about 4 feet tall and then the stems that bloom start and are about 3 ft. When is blooms the weight of the flower pulls the stems down, I tried to support with twine but that caused the stem to break when the flowers bloomed.

How do I get the stem stronger so they can hold the weight of the flowers?
I also need to water everyday because it will fade and the leaves will curl. When we have a good summer and it is not so blistering hot the tree requires less watering. When I water I use the hose with a slow trickle for about 1 hour or is there a better way to water?

Thank you and appreciate all the help I can get for this beautiful plant.

Stacey Hirvela's picture
Stacey Hirvela Mon, 08/03/2015 - 12:45pm

If the stems on your Limelight hydrangea cannot support the flowers, this usually indicates that the plant needs more sun. Unfortunately, stem strength won't improve this year, but there are a couple of things you can do for a better display next year: 1) give it at least 6 hours of sun each day, ideally in the morning if you live in a hot climate 2)In late fall or early spring, prune the plant's "canopy" back by about two-thirds its total length 3) avoid heavy fertilizing, as excessive fertilizer can cause soft growth. Is your plant in a container or is it in the ground? If it is in the ground, it should not be that difficult to keep watered, so that points to something being amiss. Would you please contact us using the form here: https://www.provenwinners.com/feedback and select "shrubs" so we can talk with you directly about it?

Anonymous's picture
Anonymous Wed, 04/01/2015 - 8:14pm

Hi, I have a 12 year old honeysuckle bush and really don't know how to prune and when. We live in zone 3.
The old growth about 4 feet high and then another 3 feet of new spindly tops. We keep cutting these off but they keep growing during the summer and fall. Should I be pruning these off in the fall.
Of course I went out to prune 4 days ago and found (because of the mild winter and spring we have had) that many of the plants such as rose and clematis were already budding. I did prune them but wonder if it was too late.

Anonymous's picture
Anonymous Fri, 09/12/2014 - 9:16pm

Thank you for the informative article. Could you please comment/advise on how/when to prune Bloomerang Lilac.

Stacey Hirvela's picture
Stacey Hirvela Mon, 09/15/2014 - 1:36pm

I recommend that you do prune your Bloomerang lilac after it flowers in late spring. That's what we do here in our trial gardens, and though it delays the rebloom for a few weeks, it neatens the appearance considerably and keeps the plant growing in a more attractive, compact form. Even the brief delay in flowering is an advantage, in a way: here in Michigan, it pushes the bloom time into September, so when most things are starting to slow down in the garden, Bloomerang lilac is just starting to turn on the charm! We simply cut the branches back by about one-quarter their length, shaping the plant by eye to maintain the rounded form.

Anonymous's picture
Anonymous Fri, 09/12/2014 - 3:39pm

My lace cap turns brown, droopy and ugly by late fall so I have always cut it down, albeit ignorantly! Is it supposed to do that? It always grows back beautifully by summer just no flowers. Am I just supposed to let it alone once it turns brown and droopy? Also, I would like to move it. Is fall the time to do so?
Thank you!

Stacey Hirvela's picture
Stacey Hirvela Mon, 09/15/2014 - 1:43pm

The answers to your questions depend largely on where you live and what type of hydrangea you are growing. You can send us a direct meessage by clicking the "Questions? Feedback? We're listening" arrow to your left with more information. Until we hear from you, here are some thoughts - it sounds like your plant is not getting enough water and/or it is getting too much sun. Moving it may be the answer to that, and I would definitely recommend a 2--3" thick layer of shredded bark mulch to help keep the roots cool and conserve moisture. As for moving it, if you live in a mild climate (say, zone 7 or warmer), now is a fine time to move it. If you live in a cold climate (zone 6 and lower), I would wait until spring.

Anonymous's picture
Anonymous Sun, 04/13/2014 - 10:17am

Hello. I'm trying to found out where to plant my new Quice Shrub. It is beautiful and healthy right now, but needs to get in the ground quick. Please advise a.s.a.p., Thank you so much for your help.

JoDee
Raleigh, NC

Stacey Hirvela's picture
Stacey Hirvela Mon, 09/15/2014 - 1:48pm

Hi JoDee - sorry we didn't see your comment earlier! Double Take quince do best in an area where they get at least 5 hours of sun.

Anonymous's picture
Anonymous Sat, 02/01/2014 - 12:41pm

Hang on, Let's Dance was sold to me as a hydrangea that bloomed on old AND new wood. According to this article, it blooms on old wood. Period. What gives?

Pauline

Anonymous's picture
Anonymous Tue, 05/27/2014 - 11:52am

Read the article again. You read it incorrectly.

Stacey Hirvela's picture
Stacey Hirvela Tue, 02/04/2014 - 1:15pm

Hi Pauline - Great question. Let's Dance hydrangea does indeed bloom on old AND new wood. However, you'll get the best show out of your plant by protecting the old wood flower buds. Relying solely on flowers to form on the new wood deprives you of several weeks of flowering (since the new wood flowers appear after the old wood ones), and we want you to enjoy the best floral display possible on your hydrangeas.

Anonymous's picture
Anonymous Fri, 06/28/2013 - 11:03am

I have tried to change the zone and can't find a way to do it. It is set on Kansas and I'm in the boreal forest of Minnesota. How do I do it

Stacey Hirvela's picture
Stacey Hirvela Tue, 02/04/2014 - 1:22pm

If our website is putting you in a different zone than you live in, it is because it is drawing that information from where your internet service provider is based instead of where you actually live. The best way to get it to reflect your actual zone is to create an account with your zip code and it will reset.

Anonymous's picture
Anonymous Wed, 05/29/2013 - 11:34am

Eek! Thank you for the advice; there are three reputable nurseries in my area, so I'll do as you recommend.

Anonymous's picture
Anonymous Sat, 05/25/2013 - 9:23pm

my japanes maple is out of control. how do u cut this with

Evelyn in Oregon's picture
Evelyn in Oregon Sat, 05/25/2013 - 12:51pm

I posted this question earlier, but hadn't created an account yet. We have an old double mock orange "shrub" (we've lived here 35 years and the mock orange was well-established when we moved here). Last year, the first leaves at the tops of branches turned black; we pruned about 1/3 of the wood after blooming. This spring, the younger wood sprouted leaves, which died almost immediately. About 2 feet down, the leaves are very healthy, so now I have this leafy plant with bare "sticks" at the top. Can I prune those dead parts, or do I need to prune from the bottom?

Stacey Hirvela's picture
Stacey Hirvela Wed, 05/29/2013 - 12:11pm

Hi Evelyn - it sounds like your mock orange is getting nipped by cold weather after the leaves emerge. Go ahead and prune off the bare portions now.

Anonymous's picture
Anonymous Sat, 05/25/2013 - 1:34pm

Hi, Evelyn! I had some glorious Mock Orange bushes when I lived in San Jose, Ca. I can tell you that black leaves are not normal. I would suggest before you do any more cutting that you take a specimen, in a sealed plastic bag, to a reputable nursery where they can diagnose what is ailing it. It sounds like it has a virus, and will probably need to be treated. If you prune it, it could cause it more stress, weaken it, and cause even more damage to them.

Good luck!

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