Protecting shrubs from heavy snow, ice and the plow

Which shrubs break under snow?

Snow does its damage by weight. University of Minnesota Extension lists upright evergreens such as arborvitae and juniper among the plants most likely to be bent and broken by snow and ice, along with trees that have more than one main leader and clump-form trees such as birch. Iowa State Extension adds weak-wooded trees like Siberian elm and silver maple.

Columnar arborvitae, popular as privacy screens and living fences, are the classic case. MSU Extension names 'Green Giant', 'Emerald Green' and 'DeGroot's Spire' as varieties that do not stand up well to heavy snow or ice loads: the stems bend open and some break. MSU's example was a November storm that began as rain and changed to wet, heavy snow.

Foundation shrubs get hurt differently. After the hard winter of 2013-14, MSU Extension described yews and junipers buried in packed snow and shrubs under the eaves reduced to rubble by snow shoveled off roofs. Brittle-wooded species were hit hardest, and MSU warned that lilacs and rhododendrons might need heavy renewal pruning.

How do you protect shrubs before the first heavy snow?

Tie upright evergreens. MSU Extension's advice is to wrap them at the beginning of winter to keep the top branches together and upright. Burlap works and also slows hungry deer; landscape wrap, heavy cloth strapping tape or bungee cords work too. University of Minnesota Extension suggests strips of carpet, strong cloth or nylon stockings. The goal is support, so use something wide and soft.

Take it off in spring. MSU and Minnesota both stress removing the wraps once the threat of snow is over. Left on, they girdle the stems.

Screen roadside evergreens. Minnesota Extension recommends burlap on the south, southwest and windward sides of evergreens, with the top left open for light and air, and notes that burlap barriers may protect some plants from salt spray thrown by traffic and snowplows. The salt injury itself is covered in salt-burned grass and shrubs.

What should you do during and after a storm?

Iowa State Extension's advice: gently shake snow from the branches, or brush it off with a broom using upward strokes. Sweeping downward adds strain to branches that are already bent.

Ice is different. Let ice-coated branches melt on their own. Beating ice off branches breaks more of them than the ice does.

Late in winter, leave shrubs buried in old, packed piles alone. After the 2013-14 winter, MSU Extension's advice was not to dig and shake buried plants, but to let the snow melt and then assess the damage. Snow itself is not the enemy: Minnesota Extension notes that snow cover insulates plants from wind and subzero temperatures.

How do you keep plowed snow off shrub beds?

Plowed snow is packed, heavy and salty, and a pile on a bed stays for weeks.

• Stake the bed edges before the ground freezes, so the bed is visible under snow. See driveway markers.
• Pile on lawn, not beds. Where to pile snow at home has the full list of places snow should not go.
• Tell your snow company. A bed at the edge of the drive, or a hedge that must not be buried, belongs on your stop notes so the crew knows before the first storm.
• Watch the roof line. If you rake a roof, or snow slides off it, decide where it lands before it lands on the rhododendrons.

What do you do with broken branches in spring?

1. Wait for the melt, then look closely. MSU Extension warns that broken stems on plants such as boxwood can stay green for a while and brown out later in the season.
2. Leave bent but unbroken branches. Many bounce back over the growing season. MSU says bent arborvitae branches can sometimes be tied back into position, but training ties should stay on no more than two seasons or they girdle the branch.
3. Prune broken branches cleanly. Minnesota Extension says to cut close to the branch collar at the base of the limb, not to leave stubs, and on larger limbs to start with a cut from underneath so the bark does not tear. Wound dressing is not normally needed.
4. Prune between snowmelt and late spring. MSU says pruning can be done from the time the snow recedes until late spring.
5. Call an arborist for anything you cannot do safely from the ground or a small stepladder, which is MSU's rule of thumb. Minnesota adds that large trees with wide-spreading leaders should be cabled by a professional, and that a chainsaw should never be used above shoulder height or from a ladder.