When to Plant Wildflowers in London, ON – 2026
Published: April 27, 2026
London is in Canadian Zone 6a (southwestern Ontario temperate). Last spring frost averages May 3; first fall frost October 20; the growing season runs about 170 frost-free days. Plant wildflowers in London from late april through early may or late october..
Wildflowers Planting Window for London, ON
Sow wildflower seed mixes in early spring (before last frost — many need cold stratification) or in fall for next-spring bloom. Best results: prepare bare soil, scatter seed, press in. Many wildflowers require no care once established.
For London, ON specifically, the recommended planting window is Late April through early May or late October.. London has 150-170 frost-free days — adequate for most warm-season crops when transplants go in by late May. The region's rich soils support heavy feeders like tomatoes and brassicas with minimal amendment.
Canadian native wildflower mixes are reliably hardy in their native zone — choose Prairie, Boreal, Eastern Woodland, Pacific, or Atlantic mixes appropriate to your Canadian region.
Best Wildflowers Varieties for London, ON
For London, ON (Canadian Zone 6a), choose varieties rated for your zone or one zone colder for reliable winter survival. The Canadian-bred or tested varieties below perform well in Ontario conditions.
Purple coneflower, blanketflower, prairie smoke, native asters, native milkweed. Source from Canadian native plant nurseries (Wildflower Farm, Prairie Originals).
Wild bergamot, black-eyed susan, native columbine, woodland phlox, wild geranium.
Camas lily, native lupine, Oregon iris, columbine, wild Oregon grape (low-growing native species).
Fireweed, wild rose, bunchberry, Labrador tea — native species for Northern Ontario, Quebec, and Yukon gardens.
Wild aster, milkweed, beach pea, native goldenrod. Salt-tolerant species for coastal Atlantic gardens.
How to Plant Wildflowers in London
Sow method: direct (scatter seeding). The steps below adapt the general planting advice for London, ON's climate and timing.
- →Choose a region-specific or state-specific seed mix; avoid generic national mixes that include species inappropriate for your climate.
- →Prepare bare soil by removing existing vegetation — scalp existing turf, till, or smother with cardboard for one full season before sowing.
- →Sow wildflower seed in fall (October through November) for next-spring bloom OR very early spring (March through April) when soil is still cold but workable.
- →Mix seed with sand at 1:4 ratio for even distribution; scatter by hand or with a broadcast spreader.
- →Press seed into soil with a roller or by walking on it — do NOT bury seeds, most need light to germinate.
- →Water lightly twice daily for the first 3 weeks until germination; reduce to weekly until established.
Frequently Asked Questions about Wildflowers in London, ON
When can I plant wildflowers in London?
Plant wildflowers in London from late april through early may or late october. based on the city's Canadian Zone 6a. Last spring frost: May 3; first fall frost: October 20; frost-free growing season: 170 days.
What Canadian zone is London?
London is in Canadian Zone 6a (USDA equivalent 5b). The climate is southwestern ontario temperate. London has 150-170 frost-free days — adequate for most warm-season crops when transplants go in by late May. The region's rich soils support heavy feeders like tomatoes and brassicas with minimal amendment.
Are wildflowers winter-hardy in London?
Canadian native wildflower mixes are reliably hardy in their native zone — choose Prairie, Boreal, Eastern Woodland, Pacific, or Atlantic mixes appropriate to your Canadian region.