Planning a pollinator garden that supports insects from early spring through late fall requires selecting plants whose bloom periods connect across the full growing season. This calendar focuses on Ontario and the adjacent Great Lakes region — USDA Hardiness Zones 5–7, Canada Plant Hardiness Zones 5b–7a — though many of these species range across much of eastern Canada.
Bloom times listed here are typical ranges for southern Ontario. Plants in northern Ontario, Quebec, or Manitoba may flower two to four weeks later. Actual timing varies with local weather conditions each year.
April to Early May: Spring Ephemerals and Early Bloomers
The first pollinators of the year — including queen bumblebees emerging from winter dormancy and small native bees of the genus Andrena — require early nectar and pollen sources. Spring ephemerals complete their growth and bloom before the forest canopy closes.
Bloodroot (Sanguinaria canadensis)
One of the earliest native bloomers in Ontario, bloodroot opens white flowers in April in woodland gardens. It is short-lived above ground but provides early pollen for mining bees. Requires part to full shade and rich, moist soil.
Wild Columbine (Aquilegia canadensis)
Blooms from late April through June. The red and yellow tubular flowers are well-suited to long-tongued bees and early hummingbirds. Tolerates dry, rocky conditions and partial shade — useful for woodland edges and rocky garden areas.
Wild Ginger (Asarum canadense)
A groundcover rather than a pollinator plant in the traditional sense — its small brown-purple flowers bloom at soil level in April and are pollinated by fungus gnats. Valuable as a larval host plant and for ground cover in shaded areas.
Late May to June: Transition Season
As temperatures stabilize, a second wave of native species begins flowering. This period overlaps with the early flight of many solitary bee species that have overwintered as pupae.
Wild Geranium (Geranium maculatum)
Blooms in May and June in part shade to sun. Provides pollen for a range of small and medium native bees. One of the most adaptable native wildflowers for Ontario gardens, tolerating average garden soil.
Native Violets (Viola spp.)
Several violet species native to Ontario bloom in May. They serve as the exclusive larval host plant for fritillary butterflies, including the great spangled fritillary. Even small violet patches in a garden can support fritillary reproduction if the site is suitable.
Canada Anemone (Anemone canadensis)
Blooms from late May into July and spreads by rhizome to form colonies. Provides abundant pollen for small native bees. Can become aggressive in moist, fertile soils — best planted where spread is acceptable.
July to August: Peak Pollinator Season
Mid-summer is the highest-activity period for most Ontario pollinators. Bumblebee colonies reach peak size, monarch butterflies are in their summer breeding phase, and the widest diversity of native bee species is active.
| Plant | Scientific Name | Bloom Period | Key Pollinators |
|---|---|---|---|
| Purple Coneflower | Echinacea purpurea | July–September | Bumble bees, mining bees, specialist bees |
| Wild Bergamot | Monarda fistulosa | July–August | Bumblebees, long-tongued bees, clearwing moths |
| Black-eyed Susan | Rudbeckia hirta | June–September | Wide range of bees, butterflies, beetles |
| Cardinal Flower | Lobelia cardinalis | July–September | Ruby-throated hummingbird, bumblebees |
| Swamp Milkweed | Asclepias incarnata | July–August | Monarch butterfly (larval host), bumblebees |
| Tall Meadow Rue | Thalictrum pubescens | June–August | Small native bees, hover flies |
Black-eyed Susan (Rudbeckia hirta)
One of the most ecologically generalist native flowers for Ontario gardens. Its flat, open flower head is accessible to short-tongued bees, beetles, and many butterfly species. Blooms over a long period and self-seeds freely on disturbed ground. Native to open meadows and roadsides across Ontario.
Purple Coneflower (Echinacea purpurea)
A high-value plant for mid-summer bumblebee foraging. The central cone provides landing structure for large bees, and the pollen is gathered by a number of specialist bees. Prefers well-drained soil and full sun. Tolerates dry conditions once established — a practical choice for Ontario's variable summer rainfall.
September to October: Late Season Bloom
Late-season flowering plants are critical. They support bumblebee queens building fat reserves before hibernation and provide nectar for migrating monarch butterflies from late August through early October.
Canada Goldenrod (Solidago canadensis)
Arguably the most ecologically valuable late-season plant in eastern Canada. Blooms from August into October. Supports a documented diversity of bee, butterfly, and fly species. Goldenrod pollen is heavy and sticky — it does not cause hay fever (airborne ragweed is the cause). Spreads aggressively by rhizome; better suited to naturalized areas than formal garden beds.
New England Aster (Symphyotrichum novae-angliae)
Blooms September to October with purple-pink flowers. One of the most important nectar sources for late-season bumblebee queens and migrating monarchs. Tolerates moist conditions and full sun. Pairs well with goldenrod for late-season habitat value.
White Snakeroot (Ageratina altissima)
Blooms August to October in shade or part shade — filling a late-season niche in woodland gardens where most sun-loving plants have finished. Provides nectar for small native bees and late-season butterflies including Eastern comma and question mark.
Planning a Continuous Bloom Sequence
A useful approach for small yards is to select at minimum one native species blooming in each of these windows: April–May, June, July, August, and September–October. Five well-chosen plants can provide nectar continuity across the full season.
Bloom overlap is also important. When one species is finishing, another should already be open. A gap of more than two weeks in nectar availability can reduce the bee population a garden can support. For most Ontario conditions, the most common gap occurs in early June — between the spring ephemerals finishing and the summer perennials opening. Wild geranium and native clematis (Clematis virginiana) are useful bridge plants for this period.