How To Prune Upright Junipers

How-To's · Written by Roger

104 Comments

There are a number of varieties of upright juniper. Some of the more common ones are: Torialosa, Robusta, Blue Point, Moonglow, Pathfinder, Skyrocket and Wichita Blue.

This category of juniper fills a useful design niche in the landscape. Most stay relatively narrow, yet grow tall. Sometimes referred to as columnar or fastigiate.

Typically they are very hardy, drought tolerant, and adaptable to a variety of conditions.

Often, however, upright juniper are not pruned, but allowed to “go-it on their own”.  This usually causes an open, lanky growth habit.  As a result they have a less than stellar reputation.

Once you understand the characteristics of upright junipers and how to care for them, they’ll become a useful plant in your landscapes.

A Common Characteristic Not Talked About But One You Need To Know

Qualities that make most upright junipers useful in landscape design are:

  • their narrow form
  • their hardiness
  • their unique texture

There’s another characteristic that’s common to most, and that’s how they grow.  All their growth energy goes to the terminal ends of the main branches. If not “selectively pruned” regularly these branches keep getting longer and heavier.  This causes each branch to stay thin with minimal side growth and eventually pull away from the center of the plant.

upright juniper prunedLost Cause?… Not Necessarily

In the picture above is an upright juniper we planted a few years back.  This was a tough spot to select a plant. The space was narrow, but height was needed.  The exposure was full sun so the heat got intense in the summer.

This upright juniper (sorry, I don’t remember the exact variety) fit the bill.

But look what happened.  The maintenance company  either overlooked the pruning, or didn’t know how.

So is this plant now a lost cause? Not at this point. You can still save the plant and reverse its decline by:

  • “Selectively” pruning back the terminal end of each branch to reduce its length and weight.
  • Using Arbor Tie to support the sagging branches by guying them to the center stem of the plant.

upright juniper branch tiedPruning the terminal end of each branch removes the apical bud and encourages lateral or side buds to grow.  This naturally makes the plant grow fuller and stronger.

The Arbor Tie lets you pull the branch back to its correct position and hold it there.  These ties should be temporary until the branches get stronger and hold their position on their own.  This might take 2 or 3 years.

Even though the Arbor Tie is temporary you must make sure there is room for growth and movement.  This PDF on Arbor Tie shows some uses and applications, but you can improvise too.  This is great stuff and I keep a roll in my truck for all kinds of situations.

The picture below shows the upright juniper after being pruned and “arbor-tied”.  Notice how selective pruning maintains the natural character of the plant.

If you use a calendar program like in Microsoft Outlook, or some other scheduling system, set a date to check the arbor ties (e.g. once/year). Don’t forget about them.  They must be monitored and eventually removed.

upright juniper pruned properlyThe Benefits of Rescuing Plants Poorly Maintained

You have to use your judgement here because sometimes it just doesn’t pay to put in the time and effort. In this particular case the task took me 20 minutes; with a good outcome – well worth it. Once again you have to compare the cost of repair (and the expected results) with replacing the plant.

Also, we all like to see a plant saved if possible and there can be real value there for the ecologically-minded homeowner.  Many customers will really appreciate the effort and professionalism.

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    104 Responses to “How To Prune Upright Junipers”

    1. Boris Says:

      Hello Roger,

      I am living in Texas, Houston area. I would like to plant several blue point junipers about 2-2.5 feet from a concrete walkway that has metal arming inside. It would be an optimal place for my home landscape design. Could the roots destroy the walkway? Is concrete a toxic substance for juniper roots at this close distance? My soil is heavy clay, but I planted 3 years ago many local wild junipers on my lot, mixing clay with organic and light clay that I have in some area of my lot. They are in very good condition. I am not sure about success with blue point junipers.

      Thank you.

    2. Irina Says:

      Hi Roger, with blue point juniper, I am not clear, I can only prune green branches? all branches become brown closer to the main trunk but there is green foliage. So, do not prune where the branch became brown?

    3. Roger Says:

      Boris,
      Junipers are very hardy by their nature — including adaptive to a variety of site conditions. The concrete walkway should not cause a toxic affect on the juniper.

      I think it’s smart you’re mixing in organic matter and light clay (from elsewhere on-site) to amend the soil. Although junipers can tolerate some wet soil conditions temporarily, they are not going to do well if the soil is constantly wet.

      With regard to the blue point juniper posing a threat to the concrete walk, it’s hard to say. You said the concrete walk has “arming” inside — I imagine that’s reinforcing of some sorts like re-bar. That’s certainly helpful. But I’m thinking that when the blue point juniper mature and get much larger they could affect the level of the walkway — especially if the walkway is not that wide.

      2-2.5′ is not a great distance from the walkway. And blue point juniper will want to ultimately grow over the walk. Pruning will help contain the plant, but eventually it will want to get wider. If you think long-term to when the plant is maybe 10′ high and 6-7′ wide, you can imagine a heavy, woody plant close to your walk.

      I certainly don’t want to discourage you because you could go ahead with your plans, prune diligently and keep an eye on their development. With that you’ll probably get a good number of years out of the plant(s) and spot any problems early — long before any real damage would occur.

    4. Roger Says:

      Irina,
      Exactly. It becomes very difficult for the plant to rejuvenate (push new growth) from branches that are bare and/or brown.

      Realize, however, that you may also be able to prune back heavy growth/branches well into the interior without plans for it to necessarily grow back. But rather look forward to adjacent branches (next to that now missing branch) to push lateral growth and fill in the space.

      With large, overgrown plants it often becomes a combination of the two pruning techniques, i.e. prune back aggressively the heavy wood (into the interior), and prune more lightly the adjacent growth.

      I hope this makes sense.

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