When to Plant Lavender in Ottawa, ON – 2026
Published: April 27, 2026
Ottawa is in Canadian Zone 5b (continental inland). Last spring frost averages May 6; first fall frost October 6; the growing season runs about 153 frost-free days. Plant lavender in Ottawa from may (after last frost, before victoria day)..
Lavender Planting Window for Ottawa, ON
Plant lavender in spring after last frost (Zones 5–7) or fall (Zones 8–9). Needs full sun, excellent drainage, and alkaline to neutral soil (pH 6.5–7.5). Avoid clay soils — lavender roots rot in wet conditions.
For Ottawa, ON specifically, the recommended planting window is May (after last frost, before Victoria Day).. Ottawa Valley winters are harsh. Choose short-season tomato varieties under 70 days (Stupice, Sunrise, Sub-Arctic Plenty) and transplant only after the May long weekend. Fall garden extends the productive season into October with cold-tolerant greens and brassicas.
English lavender (Lavandula angustifolia) is hardy to Zone 5 — survives -28°C with good drainage and snow cover. 'Hidcote' and 'Munstead' are the most cold-tolerant. Spanish, French, and Italian lavenders are tender and survive only in Zone 7+ (BC coast).
Best Lavender Varieties for Ottawa, ON
For Ottawa, ON (Canadian Zone 5b), 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.
Compact (45 cm), deep purple flowers. Most cold-hardy named cultivar. The standard for Ontario, Quebec, and Atlantic Canada.
Slightly larger (60 cm), softer mauve flowers. Earlier bloomer than 'Hidcote'. Equally cold-hardy.
Patented hybrid bred for humidity tolerance and slightly extended cold hardiness. The best choice for Ottawa and Montreal Zone 5a.
Hybrid of English × Spike lavender. Larger plant (90 cm), longer flower spikes. Higher essential oil yield than English types.
Slightly more cold-hardy than 'Hidcote' — the best choice for Alberta gardeners attempting lavender in Zone 4.
How to Plant Lavender in Ottawa
Sow method: transplant (spring or fall). The steps below adapt the general planting advice for Ottawa, ON's climate and timing.
- →Choose a site with full sun (8+ hours) and excellent drainage — sloped beds, raised beds, or rocky soils are ideal.
- →Test soil pH; amend with lime to bring pH to 6.5–7.5 if below 6.5.
- →Improve clay soils with 30% pumice or coarse sand mixed in — never plant lavender in unamended clay.
- →Space plants 60–90 cm (2–3 ft) apart for English lavender; 90–120 cm (3–4 ft) for Lavandin.
- →Water deeply once at planting; reduce to once every 10–14 days for the first month, then minimal irrigation.
- →Skip mulch close to the crown — wet mulch causes crown rot. Use coarse gravel or pea stone if mulch is desired.
Frequently Asked Questions about Lavender in Ottawa, ON
When can I plant lavender in Ottawa?
Plant lavender in Ottawa from may (after last frost, before victoria day). based on the city's Canadian Zone 5b. Last spring frost: May 6; first fall frost: October 6; frost-free growing season: 153 days.
What Canadian zone is Ottawa?
Ottawa is in Canadian Zone 5b (USDA equivalent 5a). The climate is continental inland. Ottawa Valley winters are harsh. Choose short-season tomato varieties under 70 days (Stupice, Sunrise, Sub-Arctic Plenty) and transplant only after the May long weekend. Fall garden extends the productive season into October with cold-tolerant greens and brassicas.
Are lavender winter-hardy in Ottawa?
English lavender (Lavandula angustifolia) is hardy to Zone 5 — survives -28°C with good drainage and snow cover. 'Hidcote' and 'Munstead' are the most cold-tolerant. Spanish, French, and Italian lavenders are tender and survive only in Zone 7+ (BC coast).