The Role of Mulching in Winter Tree Prep

Winter presents new challenges for trees—rapid temperature fluctuations, drought, and heavy ice on the branches. Mulching is an important part of preparing your trees for winter and is a powerful tool for insulating the roots of your trees and helping them retain moisture.

We want to review some helpful winter tree care tips for mulching and how Green Drop can help you keep your trees healthy and thriving every season.

The Importance of Mulching in Winter

A strategically applied layer of mulch helps protect tree roots from the rapid freezing and thawing cycles of Canadian winters and creates a stable environment for growth and nutrient absorption.

Mulch provides a barrier between snow and ice and the roots of your trees, helping mitigate the risk of soil and frost heaving. Well-mulched trees before winter grow sturdier and taller than trees forced to survive the winter with dried-out, cold soil or, worse, roots exposed to snow, ice, and other extreme elements.

Top Benefits of Mulching Your Trees for the Winter

Mulching around your trees before winter does more than make them aesthetically appealing. The practice has many benefits for the health of your trees. Mulching has been shown to:

• Improve soil health
• Prevent soil erosion and compaction
• Suppress weed growth
• Protect tree roots from weather damage
• Regulate soil temperature in icy conditions
• Help retain moisture during winter droughts
• Prevent common winter pests

Different Types of Mulch for Winter

There are several different kinds of mulch you can use to prep your trees for winter, like:

• Clean straw or hay. Using clean straw or hay works well to insulate the tree roots from harsh temperatures while simultaneously protecting the soil from water evaporation.
• Torn newspaper. This is an economical and environmentally friendly way to mulch around your trees in the winter and helps prevent soil erosion. Plus, typically, newspapers break down over the course of just one season, unlike inorganic mulches.
• Chopped or shredded tree bark. Chopped bark is one of the most common mulches in use today and is a great way to use up wood scraps that ordinarily would serve no other purpose. Wood mulch can be made from dead trees, pruned limbs from living trees, and tree stumps. Recently, mulch manufacturers have been using wood chips from ground up shipping pallets.
• Grass clippings or leaves. Repurposing grass clippings or leaves from the last mow of the season as tree mulch not only recycles organic matter but also enriches the soil with nutrients as they decompose. This is especially important ahead of winter when nutrients will be less available in the soil.
• Evergreen trimmings. Like grass clippings, you can use pine needles, evergreen boughs, and other trimmings to mulch around your trees. Just be wary of pests that may be present, and be sure to shake everything out well before you start mulching.
• Inorganic mulch. Stones, pebbles, and other inorganic mulches provide a low-maintenance mulch that's effective, visually appealing, and long-lasting. Gravel and similar mulches smother weeds while facilitating moisture retention and creating a clean, inviting look.
• Rubber mulch. Rubber mulch is often used around municipal trees and as a cover for playgrounds. This sustainable solution uses recycled materials that last a long time, removing the need for frequent upkeep. Rubber retains heat and insulates very well, which is an excellent choice for Canada’s frigid winter climate. You can expect rubber mulch to last 10 years or more.

Helpful Tips for Applying Mulch Around Your Trees

Mulching around your trees is a process, so many homeowners rely on tree care professionals like the GreenKeepers at Green Drop to help them prepare their trees for winter. Here are a few helpful tips you can try now:

Start by Removing Old Mulch

Start the mulching process by removing and throwing away old, decomposing mulch around your trees. You want to have a clean slate for the new layer of mulch without bringing in any bacteria, fungi, or pests from the old mulch.

Be gentle when removing mulch around your trees; the roots are usually soft and damp. You want to avoid nicking or cutting into the roots or the tree's stump while removing decayed mulch.

Trim Roots and Pull Weeds

Before applying the new mulch around your tree, take the time to trim away any visible surface roots, vegetation, or weeds that might be encroaching on the mulch area and competing with your tree for nutrients.

Your tree needs all the nutrients it can get during the winter without other vegetation soaking it up instead. You should be able to apply a flat layer of mulch evenly around the base of your tree without bumps from roots, weeds, or other unwanted plant material.

Avoid Using Dyed or Coloured Mulch

Dyed or coloured mulch is traditional wood chips or shavings that have been soaked in a dye and allowed to dry. This mulch is often in shades of rust, black, and brown. While most dyes are safe, coloured mulch may be made from materials that could harm your trees.

According to The Spruce, dyed mulch may be made from old, recycled wood that was once treated with chromated copper arsenate (CCA). This compound can raise the arsenic levels in your soil and cause damage to your trees, surrounding area, and even nearby plants.

While CCA has been prohibited by the Government of Canada since 2003, it's hard to know for sure that mulch made from recycled materials doesn't contain wood previously treated with CCA.

Apply the Right Amount of Mulch

How deep your tree mulch is plays a crucial part in how effective it is at retaining moisture and insulating the roots of your tree later on during the winter. A layer that’s too thin won’t do much in shielding the roots from snow, ice, and temperature fluctuations, but a layer that’s too thick could end up rotting with moisture that can’t adequately evaporate from all of the mulch.

A good depth for tree mulch is 2 to 4 inches or 5 to 10 centimetres. Spread the mulch evenly in a donut-shaped ring around the base of your tree, being careful to avoid stacking your mulch against the trunk. This promotes disease and decomposition around your tree.

Make Your Mulch Thinner Near Your Tree and Thicker at the Edges

When applying mulch to the base of your tree, make it a little bit thinner towards the center of the mulch around your tree. It should be thicker towards the edges, creating a little “well” for collecting water at the tree trunk.

Stacking your mulch in a mound or hill around your tree causes water to run off the mulch and away from your tree. If possible, you should mulch all the way out to the tree's drip line.

Surround Your Mulched Tree with a Border

While it's not completely necessary to surround your mulch "donut" with a border, this can be helpful to contain the mulch in the specific area you want it and prevent it from washing away during storms.

It also enhances the aesthetic appeal of your mulched tree. Consider using bricks, large stones, or other objects to create a border around the inside of the mulch to keep it from touching the tree and the outside to keep it off your lawn.

Don’t Mix Mulch and Soil

Many people think mixing mulch with soil is a good way to give their trees extra nutrients before winter. You can still refresh both the soil and mulch around your trees, but you’ll want to do it in layers. Mulch should be applied after soil in a layer on top and never mixed down into the ground.

Monitor Moisture Levels

It's important to check the moisture levels of your mulch frequently, especially after periods of rain or drought. Mulch does help retain moisture, but it can also dry out. Adjusting how much you water your trees based on the conditions of your mulch helps prevent problems caused by overwatering, like rot or fungal overgrowth.

Get Help with Your Winter Tree Prep Today from the Experts at Green Drop

Good winter prep is crucial for trees to survive the region’s frigid temperatures. Mulching is just one key part of this.

At Green Drop, our experienced arborists are winter tree care experts who can help you take the necessary steps to safeguard your trees from common cold-weather problems.Check out our tree care packages or fill out our form for an estimate.