Wasps in Mercier–Hochelaga-Maisonneuve Backyards — When to Treat, When to Wait

Published May 15, 2026 · Extermination DMP

Mercier–Hochelaga-Maisonneuve (MHM) has more compact backyards per square kilometre than almost any other Montreal borough. That density — combined with mature trees, garden sheds, and a heavy concentration of detached garages from the 1950s and 60s — creates one of the most reliable wasp environments on the island. By mid-July, almost every MHM block has at least one active nest.

Why MHM is a wasp hot spot

• Garden sheds and detached garages with eave gaps and unsealed roof vents — yellowjacket and paper wasp queens emerge from these in late April
• Mature trees and overgrown hedges giving aerial wasps multiple sheltered nesting spots
• Underground voids near patios — abandoned rodent burrows become ground-nest wasp colonies
• Compost bins and recycling producing the sugar/protein mix that fuels colony growth from June through August

When to call — and when to leave it alone

Call now if:

• The nest is within 3 metres of a doorway, deck, kid's play area, or pool
• You can hear or see steady traffic in and out within 24 hours of first noticing it
• Anyone in the household has a known wasp allergy
• The nest is inside a wall cavity, under a deck, or in attic eaves — you cannot wait those out safely

It is okay to wait if:

• The nest is on a shed in the back corner of the yard with no foot traffic
• It is paper wasp (small, open-celled, slow) and not yellowjacket (enclosed, fast-flying) — paper wasps are 10× less aggressive
• It is late August and the nest is visibly declining — Quebec winter will eliminate the colony in 4-6 weeks regardless of treatment

What we find in MHM backyards

The single most common MHM wasp callout: yellowjackets nesting in detached-garage roof eaves where the soffit meets the gutter. Second most common: ground nests beneath patio stones. Third: paper wasp umbrella nests on shed door frames.

What it costs

• Single accessible aerial nest under 3m height: $185-$245
• Wall-void or attic nest requiring pyrethrin dust application: $285-$395
• Multi-nest property (3+ active): $395-$595 single visit, all nests
• Season-long prevention treatment (May spray-on prevention): $185 (cuts mid-summer wasp pressure by 60-70% on average)

DIY spray ($15 retail) is reasonable for a single visible paper wasp nest under 30cm. It is not appropriate for yellowjackets, wall-void nests, or any nest where the entry point is more than 1 metre from where you spray.

FAQ

Will the nest come back next year?

Not the same colony — wasps abandon old nests. But the same conditions that attracted this year's queen will attract next year's. The May prevention treatment addresses the conditions, not just the visible nest.

Same-day response in MHM?

Yes. Our techs operate out of Saint-Hubert and Verdun; MHM is a 15-20 minute drive. Most wasp callouts get same-day or next-morning service from May through September.