March Tree Care in Calgary: What to Do Right Now

March in Calgary is a month of contradictions. One week it is minus 20 with fresh snow on the ground; the next, a Chinook blows through and you are standing in your yard in a hoodie wondering if spring has arrived. For trees, this back-and-forth is one of the most stressful periods of the year. But for homeowners, it is also one of the best times to take action on tree care.

Here is what you should be doing right now.

1. Prune Your Elms Before the April 1 Deadline

This is the single most time-sensitive task for Calgary tree owners. The City of Calgary prohibits elm pruning between April 1 and September 30 to prevent the spread of Dutch elm disease. The elm bark beetles that carry the fungus become active once temperatures warm, and fresh pruning cuts attract them. If your elm trees need pruning, you have a few weeks left to get it done legally.

This is not a suggestion; it is a bylaw. Fines for illegal elm pruning in Calgary can be significant. If you are unsure whether you have an elm, look for the distinctive serrated, asymmetrical leaves (though they will not be on the tree yet in March, you may find dried leaves on the ground beneath it), or have an arborist identify the species.

2. Deal With Winter Storm Damage

By March, your trees have survived the bulk of Calgary's winter storms, but the damage may still be hanging in the canopy. Walk your yard and look for:

• Broken branches that are still attached but dangling
• Branches that cracked under snow load and are now resting on lower branches
• Split crotches where heavy limbs pulled apart from the main trunk
• Branches or debris lodged in the canopy that could fall unexpectedly

Address the hazards first. Hanging branches are unpredictable and can come down at any time, especially during the heavy, wet snowstorms Calgary often gets in March and April.

3. Prune Deciduous Trees While They Are Still Dormant

March is the tail end of the dormant pruning window for most deciduous trees in Calgary. With no leaves on the branches, you can see the structure clearly, make better pruning decisions, and the risk of disease transmission is at its lowest.

Good candidates for March pruning include ash, linden, birch, apple, crabapple, and most ornamental trees. Avoid pruning poplar species if the days are already warming significantly, as they will bleed sap heavily.

4. Inspect for Black Knot

Black knot is one of the most common and visible tree diseases in Calgary. It affects chokecherry, Mayday, and Schubert cherry trees, appearing as hard, black, swollen growths on branches. March is the perfect time to spot it because there are no leaves to hide it.

If you find black knot, prune the infected branches at least 15 to 20 centimetres below the visible swelling. Dispose of the infected material in the garbage, not in your compost or yard waste. The fungus releases spores in spring, so getting infected branches off the tree before warm weather arrives is critical.

5. Plan for Spring Planting

If you are thinking about planting new trees this year, March is the time to plan, not plant. The ground is still frozen or too wet to dig, and garden centres have not stocked their tree inventory yet. But you can:

• Decide where you want to plant and what function the tree should serve (shade, privacy, ornamental)
• Research species that are suitable for Calgary's Zone 3b climate
• Call 811 (Alberta One-Call) to have underground utilities located before you dig
• Consult with an arborist about species selection for your specific site conditions

6. Check Mulch and Tree Wraps

If you wrapped young tree trunks in the fall to protect against sunscald and frost cracking, remove the wraps once daytime temperatures consistently stay above freezing. Leaving them on too long creates a moist environment that can encourage bark disease and provide habitat for insects.

Check the mulch around your trees. Winter often compacts and displaces it. Rake it back into an even layer, 7 to 10 centimetres deep, keeping it pulled back from the trunk. Avoid the "mulch volcano" look, where mulch is mounded up against the bark.

7. Do Not Fertilize Yet

It is tempting to give your trees a boost as spring approaches, but March is too early for fertilization in Calgary. The ground is still frozen or thawing, and the tree's roots are not yet actively absorbing nutrients. Fertilizer applied to frozen ground will simply wash away with snowmelt, potentially into storm drains and waterways.

Wait until the soil has fully thawed and trees are actively growing, typically mid-May in Calgary, before considering fertilization. Deep root fertilization done by a professional is the most effective method for established trees.

8. Book Your Arborist Now

This is the practical advice that most homeowners overlook. Spring is the busiest season for tree care companies in Calgary, and by April, most reputable arborists are booked weeks out. If you know your trees need pruning, assessment, or removal, pick up the phone in March. You will get faster service and often better scheduling flexibility.

March is the month of preparation. The trees are still dormant but waking up. The ground is still hard but thawing. Everything you do now sets the stage for how your trees perform for the rest of the year. Take an hour this weekend to walk your property with fresh eyes.