My inbox has been filled lately with pruning questions.  Specifically, how to prune back overgrown flowering shrubs.



Chihuahuan Sage (Leucophyllum laevigatum)
You may be wondering why you need to severely prune back overgrown shrubs?

Well, as you can see from the photo, above – as a shrub’s branches age, they produce fewer leaves and flowers.  As time passes – these branches die, which leave ugly, bare areas.

Here are a few more examples of overgrown shrubs that need to be severely pruned back…

‘Thunder Cloud’ Texas Sage (Leucophyllum candidum ‘Thunder Cloud’)

‘White Cloud’ Texas Sage (Leucophyllum frutescens ‘White Cloud’)
You may think the formally pruned sage shrubs in the photo above, look okay besides being a bit on the large side.  

But, what you don’t see is the large amount of dead branches inside.  In reality, these shrubs are covered in a very thin layer of growth.

Here is an example of old Cassia (Senna nemophila) shrubs that have only been pruned formally.  You can see that there are more dead areas then live growth.

So, how do you go about severely pruning old, overgrown shrubs back?

First of all – don’t do this during cooler months because it will take your shrubs a very long time to grow back.  In addition, it can make frost-tender shrubs more susceptible to frost damage.  Wait until spring for pruning back summer-flowering shrubs such as bougainvillea, sage, oleanders, etc.

You need a good pair of loppers and sometimes a pruning saw and you are ready to go.  Simply prune your shrub back until there is about 1 – 2 ft left (some people go back until there is only 6″ left).

Hedge trimmers can help if you use them to remove the outer part of the shrub and then you can get your loppers inside to prune off larger branches toward the base.

Below, are photos of ‘Rio Bravo’ Sage (Leucophyllum langmaniae ‘Rio Bravo’) shrubs that started out overgrown, were pruned back severely, and grew back.

Overgrown shrubs.

Pruned back to 1 ft.

This is the ugly stage.  But you need to go through this ‘awkward’ stage to achieve beautiful, healthy shrubs.

I promise that it doesn’t last long…

New growth appears 3 weeks later
8 weeks after pruning.

12 weeks after severe pruning.
 You can see that the severe pruning caused the shrub to grow young, new branches that produce beautiful green growth and flowers.


**Although severe renewal pruning keeps your shrubs healthy and attractive – there are a few cases when an old, overgrown shrub won’t grow back.  It is doubtful that the Cassia shrubs, above, will survive for long either with or without severe pruning). 

This usually indicates that the shrub has declined too much and would not have survived for long even without pruning.  If this happens, you are better off replacing your shrub.**

Hand pruners, pruning saw and loppers
A good guideline for severely pruning your shrubs is to do this every 3 years or so.  Of course, you can do this every year if you like to help keep your shrubs from outgrowing their space.

I hope that this helps to answer some of your questions.

For more information on pruning, including how to prune away frost-damaged growth, you can read some or all of these previous posts….



Noelle Johnson, aka, 'AZ Plant Lady' is a horticulturist, certified arborist, and landscape consultant who helps people learn how to create, grow, and maintain beautiful desert gardens that thrive in a hot, dry climate. She does this through her consulting services, her online class Desert Gardening 101, and her monthly membership club, Through the Garden Gate. As she likes to tell desert-dwellers, "Gardening in the desert isn't hard, but it is different."

21 replies
  1. Aaron Dalton
    Aaron Dalton says:

    Excellent post. But I had thought there were certain shrubs that would benefit from renewal pruning or coppicing, and others that would not appreciate such extreme pruning. In your experience, are there some shrubs that one should definitely *not* subject to renewal pruning?

    Reply
  2. Linda/patchwork
    Linda/patchwork says:

    I have some Texas Sage bushes that need some severe pruning.
    This post came just in time.

    I wasn't sure how far back I could cut them. They look awful now.

    We inherited them, when we bought the house. No telling how old they are. But, they obviously haven't been pruned often enough.

    Thanks for the advice.

    Reply
  3. arizonaplantlady@gmail.com
    arizonaplantlady@gmail.com says:

    Hi Aaron,

    Thank you for your comment.

    There are are very few flowering shrubs that don't benefit from this type of pruning in this area of the country.

    However, camellias and gardenias, which are rarely found here (they have a hard time growing in the desert), would probably be the two that I would make an exception to severely pruning. Hibiscus would probably be another, unless it had severe frost damage.

    This was a great thought-provoking question 🙂

    Noelle

    Reply
  4. David Cristiani
    David Cristiani says:

    Great clarifications on hard-prune reality, whys and whens – especially every few years. Am doing some of that now, balancing rejuvenation and keeping OK right now for Realtor showings!

    Reply
  5. Kristen
    Kristen says:

    I'M guessing it is too late to do this type of pruning now. I am totaly new to any type of gardening, and look forward to reading up on everything you've written to help educate me.

    Reply
  6. Mae
    Mae says:

    Thank you for posting this! I inherited a 6' overgrown oleander when I purchased my house and had no idea where to begin to make it manageable.

    Reply
  7. arizonaplantlady@gmail.com
    arizonaplantlady@gmail.com says:

    Hi James,

    Your shrubs should be okay if you prune them now. Be sure to water them deeply for the next month to help them to recover and put on new growth. It can take a few weeks before you see the new growth. If your shrubs don't grow back, it's a sign that they were old and/or in declining health and wouldn't have lasted long regardless whether you pruned or not.

    I recommend doing this early in the morning or in the evening when it's cooler 😉

    Best,
    Noelle – AZ Plant Lady

    Reply
  8. Amanda Wilcken
    Amanda Wilcken says:

    Thank you for this post! I have Texas sage that I’ve been benevolently ignoring for 2 years that were previously sheared. They have a bunch of old dead growth at the center and I didn’t know how to trim without causing more harm. Now, it’s november, so the hardest part is waiting until April to trim! Thank you!

    Reply
  9. Tim
    Tim says:

    How short can I safely prune an overgrown oleander tree/shrub? It’s out of control at around 10 ft tall. I would like it to be around 4 ft but all the green leaves are on the top. The branches are really long without leaves until the top 2-3 feet. Can I cut down to a few feet even if it leaves “stumps”?

    Reply
    • arizonaplantlady@gmail.com
      arizonaplantlady@gmail.com says:

      Hi Tim,

      Oleanders can usually be cut back almost to the ground and will grow back. In a few cases, they may not grow back, which is a sign that they were declining and wouldn’t have survived long whether you pruned or not. I hope this helps!

      Reply
  10. Sue L.
    Sue L. says:

    Hi, I know this post is kinda old but i have two simpson stopper bushes that i have pruned with a hedger and now they are mostly bald inside beautiful on the outside but nothing on the inside i was wonder if i can just hand prune just the top to open it up to let some light in the center without having to cut the whole thing down is this an option i am new to all this with no green thumb whatsoever any help from anyone would be appreciated .
    thank you- Sue.

    Reply
    • arizonaplantlady@gmail.com
      arizonaplantlady@gmail.com says:

      Hello Sue,

      While I am not familiar with this particular shrub, the type of pruning that you are describing does work well with many types of shrubs. You can also prune back 1/3 of the oldest branches back to the base and do another third the next year, and so on. This is helpful if you don’t want to prune back the entire shrub at once. I hope this helps.

      Reply
  11. Jen
    Jen says:

    Hi AZ Plant Lady!

    Great post! My question…I’m in Vegas (zone 9) and I have yellow desert cassia and Texas sage shrubs. Both are about 8 years old. I pruned the cassia for the first time this spring after they ‘went to pod’ & I’ve never pruned the sage. Even though I have some really nice regrowth on one of the cassias (the other two have new growth; but it’s not as soft), l have dead growth in the center of all the shrubs. Since it’s just the beginning of August & we won’t have any frost for about 4-5 months, can I hard prune now? Or should I still wait until next spring?

    Also, the shrubs are under a tree that likes to shed needles & pods that collect in the center of the shrubs. I’m going to hazard a guess that that will choke the life out of them?

    Thank you for your help!

    Reply
    • arizonaplantlady@gmail.com
      arizonaplantlady@gmail.com says:

      Hello Jen,

      It’s important not to prune severely in summer as this is a stressful time of year for plants. Wait until spring. The older a shrub is, the harder time that it will have coming back from being severely pruned – particularly if they have been badly pruned in the past. If they don’t grow back well, or not at all, this is an indicator that the shrub wouldn’t have lived long whether or not you had pruned it. When this happens, simply replace the shrub. If a shrub has a lot of debris falling on it, it does prevent the sun from reaching its leaves, so its best to clean them off. I hope this helps!

      Reply

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