Building a Pollinator Corridor: Alberta-Native Bloom Succession Through the Season

The bloom calendar: Alberta natives by week

April – early May (the critical emergence window)

Queen bumblebees emerge first; they need nectar immediately to start new colonies. This is the hardest window to cover.

• Prairie Crocus— first bloom of the year in many parts of the province.
• Pussy Willow— pollen and nectar in March catkins, essential for emerging queens.
• Golden Bean (Buffalo Bean)
• Balsam Poplar catkins
• Marsh Marigold— if you have a wet spot.

Mid May – late May

• Saskatoon Berry— clouds of white flowers, one of Alberta’s best native bee plants.
• Chokecherry
• Wolf Willow (Silverberry)— intensely fragrant.
• Shooting Star
• Prairie Smoke

June

• Wild Rose (Prickly Rose)
• Wild Blue Flax
• Heart-leaved Alexander— Black Swallowtail butterfly host plant.
• Yellow Prairie Violetand other violets — fritillary butterfly hosts.
• Harebell
• Canada Anemone

July

• Wild Bergamot— bumblebee and hummingbird magnet.
• Blanket Flower— blooms for months.
• Purple Prairie Clover
• Giant Hyssop (Anise Hyssop)— one of the highest nectar producers in NA.
• Fireweed
• Nodding Onion
• Common Yarrow

August

• Dotted Blazing Star— monarch butterfly favourite during fall migration.
• Smooth Aster— late blue blooms.
• Showy Aster
• Northern Goldenrod— critical late-season fuel.
• Other native goldenrods (Solidago canadensis, S. rigida)

September – early October

• Late goldenrods and asters continue through first frost.
• Smooth Aster often blooms past the first light frost.
• Wild Mintif you have wet ground — late-season bumblebee food.

Design principles beyond bloom succession

1. Plant in clumps, not single plants.Most native bees are most efficient foraging from a cluster of the same species. Groups of at least 3–5 of each plant; 7+ is better.
2. Provide nesting habitat.70% of Alberta’s native bees nest in bare ground. Leave a patch of unmulched, unworked soil — ideally south-facing. For stem-nesting bees (the other 30%), leave perennial stems standing through winter and cut them to 30–40 cm in spring rather than all the way to the ground.
3. Include a water source. A shallow dish of water with pebbles (so bees can land without drowning) meets pollinator water needs without creating mosquito breeding.
4. Skip the pesticides. Even organic insecticides kill pollinators. If pests become a problem, hand-pick or hose off rather than spray.
5. Ask nurseries about neonicotinoids.Many nursery starts are treated with systemic neonicotinoids that persist in the plant for a year or more — the pollen and nectar kill bees even after you buy and plant them. Alberta nurseries specializing in natives are usually neonic-free; ask to confirm.
6. Leave leaf litter in fall. Many butterfly and moth species overwinter as pupae in leaf litter. A bare swept garden bed loses them.

A minimal pollinator corridor (10 m²)

The smallest meaningful pollinator planting is around 10 square metres. A workable recipe for that size in full sun:

• Spring anchor: 1 Saskatoon Berry shrub
• Early summer: 5 Wild Blue Flax, 3 Harebell, 3 Prairie Smoke
• Midsummer: 3 Wild Bergamot, 3 Giant Hyssop, 3 Blanket Flower, 3 Purple Prairie Clover
• Late summer: 3 Dotted Blazing Star, 3 Smooth Aster, 3 Northern Goldenrod
• Groundcover and bee habitat: Leave a 1 m² patch of exposed lean soil for ground-nesting native bees
• Water: One shallow bee-safe water dish

After the establishment year, a planting this size needs minimal maintenance: deadheading is optional, watering only in severe drought, and no fertilizer. Leave stems and leaf litter through winter; cut back in late spring after emerging pollinators have left their overwintering shelter.

Why it matters

Alberta has lost 80%+ of its native grassland to cultivation. Pollinator populations are collapsing globally — some native bee species have declined 90% in the last 50 years. An individual yard doesn’t solve this, but a network of small pollinator corridors across Edmonton, Calgary, Lethbridge, and between can connect remaining habitat and keep populations functional. Your yard can be a step in that network.