When to Plant Rosemary in Simms, Montana (59477)

Location

Simms, Montana

ZIP Code

59477

USDA Zone

Last Frost

Tuesday, May 5, 2026

📅 Planting Calendar

Start Seeds Indoors Tuesday, February 24, 2026

Transplant Outdoors Tuesday, May 19, 2026

Pro Tip: Start Rosemary seeds indoors 10 weeks before your last frost date, then transplant outdoors around Tuesday, May 19, 2026.

🌿 Plant Details

Scientific Name Salvia rosmarinus

Days to Maturity 120 days

Mature Height 24-48"

Spread 24"

Type Shrub

Fruit Size N/A

☀️ Growing Requirements

☀️

Sun

Full Sun (6+ hours)

💧

Water

Low (drought tolerant)

↔️

Spacing

24" apart

🌱

Planting Depth

0.25" deep

Seeds typically germinate in 14-21 days

Ready to Plant Rosemary in Simms?

Get your seeds now so they're ready by Tuesday, February 24, 2026.

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Growing Rosemary in Zone 4b

Rosemary (Salvia rosmarinus) is a popular garden vegetable. In Simms, Montana, which is in USDA Hardiness Zone 4b, you should start seeds indoors around Tuesday, February 24, 2026.

Your average last frost date is Tuesday, May 5, 2026. Plan to transplant your Rosemary seedlings outdoors around Tuesday, May 19, 2026, about 2 weeks after your last frost date.