Protecting shrubs from snow load and plow spray

This guide is part of our Montana Winter Property Guide and it deals with shrubs specifically. For large trees, see winter tree care and snow load. The advice below draws on University of Minnesota Extension and University of Wisconsin-Madison Extension, both cold-climate programs. We name them because they are not Montana sources, though heavy snow on a shrub works the same way here.

Which shrubs are most likely to break under snow?

Shape is the best predictor. University of Minnesota Extension lists plants with more than one central leader, upright evergreens such as arborvitae and juniper, multi-stemmed clumps such as birch, and plants with narrow crotches or included bark as most vulnerable. Heavy snow and ice bend and break branches, and they can topple whole trees.

Look at your yard with that list in mind. An upright arborvitae beside a garage has several stems held together by nothing but their foliage, and a wet snow can pull them apart.

Should you brush snow off shrubs?

Sometimes, and gently. University of Wisconsin-Madison Extension says to carefully brush away snow after a major snow event, assuming it easily comes off. If it does not easily come off or includes ice, it says the best thing is to leave it alone and let natural melting take care of it.

The reason is the delayed damage. Wisconsin warns that shaking frozen branches can cause damage that may not appear until sometime next season, when a cracked limb suddenly wilts and dies. So use a broom or your gloved hand, work from the bottom of the plant upward so snow is not dropped on lower branches, and do not whack or shake. Once a crust has formed, stop. That advice is ours from the logic of the load: the goal is removing weight without bending anything further.

Can you tie shrubs up before winter?

Yes, for upright plants with several leaders. Minnesota says to tie leaders with carpet strips, strong cloth or nylon stockings, two-thirds of the way above the weak crotches, and to remove the ties in spring to prevent girdling. Soft, wide material is the point, and it is worth writing yourself a spring reminder, because a forgotten tie is what causes the girdling.

Minnesota also recommends the longer-term fix: removing multiple leaders and weak branch attachments through pruning. On larger plants it says a professional arborist should cable main branches together. Pruning in the dormant season lets you see the structure clearly, and it is something we do as part of dormant pruning and our tree services. See tree cabling and bracing explained if you are weighing that option on something large.

Do shrub covers and wooden frames help?

Barriers help against sun, wind and spray. Minnesota recommends burlap or similar barriers for evergreens on the south, southwest and windward sides, and it says burlap barriers may protect some plants from salt spray. We cover how to set those up in our guide to protecting shrubs over a Montana winter.

We did not find an extension source that tests frames or A-frame shelters against heavy snow specifically, so treat them as common sense rather than proven. If you build one, make sure it is stronger than the snow it holds and that it does not touch the plant. The same goes for anything that could slide off a roof: if a shrub sits under an eave, read icicles and roof snow slides and consider whether that is the right place for it long term.

How much damage do plow piles do?

Plenty, and it is the easiest part of this to prevent. Wisconsin's reminder is simple: watch where snow gets plowed and piled to avoid damaging smaller shrubs. A pile is heavy and compacted, it may be full of gravel and de-icer, and it sits in place for months. It also melts last, keeping the root zone wet and cold into spring.

Decide on a pile location before the first storm. Our guide on where to pile snow covers the options, and snow stakes and markers shows how to mark what the operator cannot see once it is buried. For more on the mechanical side, see snow plow damage prevention. On our residential snow removal routes, this is a conversation worth having before the season starts rather than after the first push.

What does plow spray do to shrubs?

Salt reaches plants in two ways, according to University of Wisconsin-Madison Extension. Melted, salt-laden snow accumulates in the soil along streets and sidewalks, and fast-moving traffic and high winds disperse it as aerosol spray off wet, salted roads. Salt spray can cause severe foliar or stem injury, Minnesota adds, while salt in runoff builds up in the soil and injures roots.

Wisconsin's clues for spray injury are worth remembering. Damage is more severe on the side of the plant facing the road, plants downwind of the road show more damage than upwind, and branches covered by snow or sheltered from the road show none. Most damage occurs within 60 feet of a road and decreases with distance. For soil injury, most damage occurs within 30 feet of the road, and plants are hurt most in poorly drained soils or where runoff from salt-laden snow collects.

When does salt do the most harm?

Late, not early. Wisconsin says salt applications in late winter or early spring cause the most damage compared with earlier ones, because root systems are actively taking up water as plants break dormancy. That is a useful detail for a Montana property with a long shoulder season. The last few applications of the year near a bed may matter more than the first.

Our guide to how de-icing salt damages plants and concrete goes further into the mechanism. If a planting strip keeps failing, salt-tolerant plants for drivesides and walks is the next read.

How can you reduce salt on your own property?

Minnesota's list is practical. Clear snow quickly and apply the minimum salt needed, only where needed. Keep salt off grass and ditches, and avoid planting where salty runoff collects or near streets with heavy spray. It also suggests considering calcium chloride or calcium magnesium acetate as alternatives. Wisconsin says products containing potassium chloride are less harmful to vegetation than sodium chloride, and recommends sand for traction wherever possible.

Wisconsin also says to plow first and then apply salt, so that salt is not mixed into the snow you push onto the beds. Safety comes first on steps and walks, so use what you need there, and see sand, salt or both for traction and our ice melt guide for choosing a product. If pets use the same paths, pet-safe ice melt explains what the labels mean.

What should you do for shrubs in spring?

Wait for the snow to melt on its own and walk the beds. Remove gravel and debris that the plow left behind, and rake back what is smothering the plants. Cut broken stems back to healthy wood with clean, smooth cuts: MSU Extension forestry specialist Peter Kolb explains that a jagged break heals very slowly, while a smooth cut lets new bark cover the wound much faster, and he warns against leaving a dead stub.

Wisconsin notes that if you suspect salt injury, a soil test or foliar analysis is needed to confirm it, and that soil samples should be collected in early spring before rain leaches the salts out of the sampling area. Our guide to yard cleanup after the snow melts puts this in order with everything else.

Is it worth moving a shrub?

If it gets crushed every winter, often yes. A shrub on the inside of a driveway curve or at the end of a plow push is not going to win that argument, and no amount of tying fixes a location problem. The alternative is to change the plowing plan, or to replace the plant with something low that can be buried without breaking.

We can talk through both, since we handle landscaping design and snow and 24-hour storm services. Call (406) 215-7319 or contact us for a free estimate. Our crews work across Missoula, Lolo, Clinton and the Bitterroot Valley.

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