living a well tended life... at any age

cutting back (the good kind, in the garden)

Even the most confident gardeners I talk to admit to some level of anxiety when it comes to pruning their perennials. Fear of “hurting the plants” typically results in doing nothing at all. And while no harm will come from NOT pruning your plants, there are many compelling reasons to do so.

I’ve already covered one important gardening task – deadheading. Today’s post is about cutting back.

I cut back my plants to delay growth, achieve a more compact and attractive shape, and avoid staking.

Late-season plants such as sedum “Autumn Joy”, chrysanthemum and Montauk daisy spend most of the summer growing. If left unpruned,  by August or September they will be tall and leggy, and most likely require staking. Worse, they will often produce only a few blooms atop those too-tall stalks, resulting in an ungainly appearance.

Cutting  these plants down by half (sometime in late spring)  will reduce or even eliminate the need for staking – and you KNOW how much I hate staking!

Here’s a great example using one of my favorite perennials. Joe-Pye weed is a late bloomer that grows nice and tall and is reliably deer resistant. The problem is that it grows a little TOO tall – as high as 7 or 8 feet – and tends to lean heavily, with one lone bloom atop each stem. Take a look at this plant unpruned:

joe pye weed, unpruned

So sometime in June (or when the plants are about 2′ tall), I cut them all back by one third:

joe pye weed, cut back

In a week or so they will shoot out new leaves from where I made the cuts:

joe pye weed, 1 week after cutting back

This is what they look like two weeks later:

joe pye weed, 3 weeks after cutting back

In addition to being more compact and bushy, the plants will produce several blooms, rather than just one – and again, no staking!

Other plants that are improved by cutting back are those that grow too-tall, too-fast. Where I garden we typically get long stretches of rain in spring – this sends perennials shooting up faster and taller than usual, and by the time summer comes these plants are way too tall and in desperate need of staking. Plants like nepeta and coneflower shoot up like wildfire, and while I like some height in the garden,  I DON’T like skinny, stringy-looking stems.  So I cut back, by about half, many of my spring and summer blooming plants when they are about 12-18” high.

Take a look at two different bee balms in my garden. This plant was installed last summer – when it grew to about 18″ this spring I cut it down by half. It’s nice and bushy, compact, and covered with blooms:

bee balm, cut back

Now look at the bee balm I planted a few weeks ago:

bee balm, left unpruned

This plant is gigantic (over 5′ tall) – leggy, spindly and pretty unattractive.

Which leads me to another great benefit to cutting back:

bee balm, cut back after blooming

This is that same ugly guy from the photo above. When the flowers were finished I cut the stalks down – and look! – new leaves emerging. They probably won’t produce  blooms but the plant will look fresh and clean for the rest of the season.

It’s important to note that not all plants benefit from this type of pruning – perennials such as peonies, astilbes and alliums will not respond the way I described above, and worse – you’ll lose the blooms for that season as well. A search on-line or in a gardening book will help you determine if you should prune or not.

So what are you waiting for? Sharpen up those pruners and get out there! And as always, I’m happy to answer all of your gardening questions here!

 

9 Comments

  1. Hotly Spiced on July 5, 2012 at 6:31 pm

    Deer resistant? That’s not a problem we have to worry about here in Australia. Our troubles lie with the possums xx

    • sherisilver on July 6, 2012 at 12:24 pm

      Possums? I thought it was kangaroos!

  2. Rosa @ FlutterFlutter on July 6, 2012 at 11:43 pm

    Oh, I’ll be passing on the Joe Pye info to my parents… my dad wants to rip it out and my mom loves it. Trimming it so it’s more manageable might be a good compromise!

    • sherisilver on July 7, 2012 at 8:22 am

      Yes! It’s a great plant and even greater when nice and short – let me know if he has any questions! 🙂

  3. Kathy O'Harra on July 10, 2016 at 1:02 pm

    Joe Pye is tall with spindly upper stems holding small bud heads…..it’s 7/10/16 cut some back and get flower heads this fall? First time this has happened in a group of 10 yr. old plants. Thanks

    • sherisilver on July 11, 2016 at 2:37 pm

      Where are you located? I’m in New York and typically cut mine back starting in June so that they have time to re-leaf/bud and then bloom. Let me know!

      • Kathy O'Harra on July 11, 2016 at 3:23 pm

        Davenport, IA I think I would just cut a few to see what happens. I’m used to the flowers being the size of an 8 x 10 oblongish shape that 8-10 bumble bees smother themselves in. I’m not sure these will hold 1 bumblebee. They look healthy. Thanks for your response.

        • sherisilver on July 11, 2016 at 8:54 pm

          That’s a great idea – the plant sounds abundant enough to try a few and see what happens. Please let me know!

          • Kathy O'Harra on July 12, 2016 at 7:38 am

            thank you….after the rain. Have the best day you can make it.



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