When to Prune Blue Spruce Trees: A Seasonal Guide

Q: I have a question I am hoping you can help me with. We have four very large blue spruce in our front yard. The bottom branches have had a lot of bare spots and dead needles for the past few years. We would prefer not having to remove those branches, but it would appear inevitable. When is the best time of year to do it? Is now a good time, before the system starts up?

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Q: I have a question I am hoping you can help me with. We have four very large blue spruce in our front yard. The bottom branches have had a lot of bare spots and dead needles for the past few years. We would prefer not having to remove those branches, but it would appear inevitable. When is the best time of year to do the job? Is now a good time, before the SAP starts running?Advertisement 2Story continues belowThis ad hasn’t loaded yet, but your article continues below

The blue spruce is a popular evergreen landscape tree, prized for its striking powder blue foliage, conical shape, and natural symmetry. While blue spruces don’t require much pruning to maintain their form, occasional trimming can help shape and invigorate the tree However, timing is everything when it comes to pruning blue spruces Make the cuts at the wrong time and you risk damaging the tree.

In this comprehensive guide we’ll go over the basics of blue spruce pruning, including

  • Why pruning is important
  • Signs your tree needs pruning
  • Tools and supplies for the job
  • The best time of year to prune blue spruces
  • Techniques for pruning mature trees
  • Tips for avoiding common mistakes

Follow these seasonal tips to prune your blue spruce successfully.

Why Prune Blue Spruce Trees?

Blue spruces are slow growing evergreens that normally retain a neat, pyramidal shape without intervention. However, occasional pruning provides the following benefits:

  • Removes dead, damaged, or crossing branches
  • Thins dense interior growth to improve air circulation
  • Rejuvenates old wood by stimulating new growth
  • Maintains structural integrity and natural form
  • Directs growth by selectively removing secondary branches

Pruning is especially helpful for mature trees that become overgrown and develop dead patches within the canopy. A strategic trim can restore vigor and aesthetics.

Signs Your Blue Spruce Needs Pruning

Watch for these signs that your blue spruce could use some judicious pruning

  • Dead, dying, broken, or rubbing branches
  • Excessively long interior branches shading the center
  • Areas of thin foliage or bare interior branches indicating poor air circulation
  • Lopsided, misshapen growth
  • Excessively dense foliage overall
  • Visible decline in vigor or health

Any of these issues can benefit from careful corrective pruning when timed properly.

Supplies for Pruning Blue Spruces

Pruning blue spruces doesn’t require much specialized equipment. Have these basic supplies on hand:

  • Bypass hand pruners for smaller branches
  • Loppers for thicker branches up to half inch diameter
  • Pruning saw for large branches over half inch diameter
  • Pole pruners/saws for high branches
  • Ladder for reaching high branches safely
  • Garden gloves to protect hands from abrasive needles
  • Rags for wiping tools clean between cuts
  • Bucket of bleach solution for disinfecting tools
  • Tar or paint to cover large wound sites

Sharp, clean tools will make pruning easier and minimize damage. Avoid using hedge shears which can mangle the foliage.

When to Prune Blue Spruces

Timing is absolutely critical when pruning blue spruces. Make pruning cuts at the wrong time and you risk severe damage to the tree.

Here’s an overview of the best – and worst – times to prune:

Best Time: Late Winter

The optimal time to prune blue spruces is late winter, before any new growth emerges. Most arborists recommend February or early March for colder climates. The precise timing depends on your USDA hardiness zone and local weather patterns. Wait until the tree is fully dormant but early enough that wounds can seal before spring growth begins.

Good Time: Early Spring

Some gardeners also prune blue spruces in early spring once dormancy breaks but before new buds elongate. Time this just as the buds begin to swell. It’s riskier than late winter pruning but can work.

Avoid Summer Pruning

Never prune blue spruces in summer when actively growing. Summer pruning cuts disrupt sap flow, weaken the tree, and invite disease. The exceptions are broken, diseased, or dead branches which should be removed promptly regardless of season.

Use Caution in Fall

Fall pruning is controversial. Some experts warn against any fall pruning for blue spruces as it may impact winter hardiness. Others say fall pruning can be done safely early in the season, no later than 6-8 weeks before your first expected frost date. Pay close attention to seasonal variations in your area.

Don’t Prune in Winter

Once winter dormancy sets in, hold off on pruning until late winter. Cuts made in mid to late winter have no time to seal before growth resumes and are vulnerable to canker fungi.

Techniques for Pruning Mature Blue Spruces

Here are some guidelines for pruning overgrown, neglected blue spruces:

  • Work slowly and selectively, never removing more than one-third of the tree’s foliage at once.

  • Use proper pruning cuts – look up arborist pruning techniques online. Never stub or top trees.

  • Always cut back to a side branch or main branch collar. Don’t leave protruding stubs.

  • Remove dense interior branches shading the center of the canopy.

  • Shorten excessively long branches, but leave some ends to stimulate regrowth.

  • Remove lower branches as needed to lift the canopy, but don’t over-thin the bottom.

  • Balance top reductions with interior thinning and lower branch removal.

  • Space out pruning over successive years for best results and recovery.

Mistakes to Avoid When Pruning Blue Spruces

Some common pruning mistakes to steer clear of include:

  • Topping or shearing into a ball – destroys the natural form

  • Making cuts too close to the trunk – leads to sunburned bark

  • Pruning heavily on one side only – causes imbalance

  • Removing too much live foliage at once – risks stress and shock

  • Leaving branch stubs – invites insects/disease

  • Pruning in summer when actively growing

  • Neglecting to disinfect tools between trees – spreads disease

  • Allowing wounds over 2” diameter to go uncovered – slows healing

With careful timing and responsible methods, you can safely prune your blue spruce to maintain its beauty and vitality. Just be sure to educate yourself on best practices first and time it right!

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A: Winter never stops a gardener from planning or solving problems. In answer to your question, yes, late winter is a good time to prune evergreens like spruce. Pruning after the sap starts running can be damaging to the tree. I know that the tree might look a little “different” without its skirt of lower branches, but that look, rather than one with bare branches, is more pleasing to the eye. When it comes to aesthetics it is only your opinion that matters anyway.

Q: Every fall, I use a spade to turn my soil over and let the frost break up the big chunks. In the spring, when the ground is workable, I rototill it to break down the lumps even further. I am planning on adding some cow manure to the garden this spring. Should the manure be added and then rototill it in, or should it be added on top of the soil that has already been tilled and then just raked in?

A: When I first started gardening, I was taught that you should always dig or till the manure into the soil. But these days, there’s a movement that says spreading it on top and leaving it alone has the same effect as digging it in. The idea behind this is that the worms will break it down for you. We live in an area with a lot of clay in the soil, so I’m not sure I agree with this reasoning. Digging the manure into the soil may still be best for our gardens. Advertisement 3Story continues belowThis advertisement has not loaded yet, but your article continues below. Article content.

One of the best ways to improve the structure of clay soil is to add manure or organic matter to it. This makes me think that the faster you can work the manure into the clay zone, the faster the structure will get better. I think that tilling or digging the organic matter in is the best way to go. One word of caution about tilling, though: rototilling often can actually pack down the soil, making a hardpan layer where the tines of the rototiller hit the ground, so be careful not to till too much.

Question: I want to grow some petunia cuttings over the winter, but powdery mildew is making it hard. This was my first time trying to take cuttings, and it’s really getting annoying. I’m giving up pretty quickly. On top of the plants, everything is nice and green, but the bottoms are getting fuzzy and golden brown. Can you please tell me how I can control this problem?.

A: Garden sulphur spray is very good at controlling powdery mildew. Spray it on generously, covering all parts of the plant. Keep an eye on your plants, and if the problem seems to be getting worse or not going away, spray them again. Powdery mildew is a fungal problem that can sometimes be controlled through environmental factors. Here is a list of things to try to help prevent reoccurrences:

– Do not crowd plants together. Good air circulation between plants is important.

When covering your cuttings with something like plastic, make sure you take it off for a good part of the day so the air can flow properly.

– Water from below and always try to avoid getting water on the leaves.

Gerald Filipski is a member of the Garden Writers Association of America. E-mail your questions to filipskigerald@gmail. com He is the author of Just Ask Jerry. To read previous columns, go to edmontonjournal. com/filipskiArticle contentShare this article in your social networkTrending.

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How to Prune Spruce Trees!


What time of year do you trim spruce trees?

Spruce and fir trees don’t grow continuously all year, but they can be pruned any time because they have lateral (side) buds that will sprout if the terminal (tip) buds are removed. It’s best to prune them in late winter, before growth begins. Some spring pruning is not harmful.

Should I trim lower branches on spruce trees?

Evergreen trees such as pine, spruce, fir, Douglas-fir, and hemlock require little pruning. These trees typically have a broad, pyramidal form with low branches, and should be left intact. DO NOT remove lower branches as this destroys the natural aesthetic form of the tree. NEVER remove the main, central stem.

When to fertilize blue spruce trees?

For Blue Spruces, the best time to fertilize is in the early spring or fall. Avoid fertilizing in the hot summer months when the tree is stressed from heat.

What is the lifespan of a blue spruce?

Blue spruce is a slow-growing tree and some individuals have been reported to live for more than 600 years. Reproduction by layering has not been reported for this species. Western spruce budworm larvae feed on old needles in late April, then mine developing buds and defoliate new tree growth.

How do you prune a blue spruce tree?

Late winter is best. Use sharp, sterile shears to complete the cuts. Wear gloves when pruning to protect your hands from the fairly sharp mature needles. The foliage of the blue spruce is so dense that the tree can develop dead areas within the tree’s canopy.

When should a blue spruce be pruned?

Act only during the tree’s dormancy. Unlike deciduous trees, the blue spruce can take several seasons to defoliate its oldest lower-lying branches. These aging branches often shed their needles and begin to lose their natural bluish-green color. These branches can be removed during the dormant pruning sessions.

Do Colorado blue spruce need pruning?

As a general rule, Colorado blue spruce do not require pruning to keep their natural, attractive shape, and the tree’s slow growth makes it largely intolerant of heavy pruning. Sometimes, however, they may need light pruning to clean up the shape or trim out a broken branch.

When should I prune a spruce tree?

By submitting your information you agree to the Terms & Conditions and Privacy Policy and are aged 16 or over. If you are pruning for other than corrective reasons, plan pruning spruce shrubs or trees in early summer. Avoid any pruning in late summer or early autumn since pruning can produce new growth that may die in the winter cold.

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