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When to plant Salvia in Cass County, MN

Cass County's 139-day season only supports one Salvia planting per year. Sow between May 26 and June 9 for the best chance at full maturity before September 28.

When to Plant Salvia in Cass County, MN

Salvia splendens is a tender perennial from Brazil grown as a warm-season annual throughout the US. Its vivid, upright flower spikes in brilliant red, purple, and coral are irresistible to hummingbirds, bees, and butterflies. One of the longest-blooming annuals in the landscape — plants bloom from early summer until hard frost with minimal deadheading required.

Cass County, Minnesota is in USDA Zone 4a. The average last spring frost is May 12 and the first fall frost is September 28, giving you a growing season of approximately 139 days.

At an elevation of 938 feet, Cass County receives approximately 32.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Salvia to ensure they mature before fall.

Annual Blooms in Summer Pollinator-friendly Deer-resistant Good for cutting Fragrant
Cass County, MN (Zone 4a) Short season
139 days
Last Spring Frost May 12
139 growing days
First Fall Frost September 28

Cass County Soil Profile

Soil Type

Silt Loam

Soil pH

6.0-7.0

Drainage

Well Drained

Salvia Planting Timeline — Cass County, MN

Salvia Planting Calendar

Activity When Date Range
Start Indoors March 3 Mar 3 – Mar 17
Transplant Outdoors May 26 May 26 – Jun 9
Bloom August 4 Aug 4 – Oct 6

· 12" apart · Rows 18" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April
May Transplant Outdoors
June Transplant Outdoors
July
August Bloom
September Bloom
October Bloom
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 5.5–7 · Your soil: N/A

🗺️ USDA Zone

Zone 4a

📆 Growing Season

139 days in Cass County

Growing Tips for Cass County

Start indoors 8-10 weeks before last frost; seeds need 65-70°F soil and light to germinate (surface-sow, do not cover). Transplant after last frost when soil has warmed. Salvia is frost-sensitive — even a light frost kills plants. Pinch spent spikes to encourage continued bloom. Tolerates heat and humidity well once established. In zones 9b-11b can be grown as a short-lived perennial.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Salvia in Cass County, MN?

Cass County is in Zone 4a with an average last frost of May 12. Plan your Salvia planting based on this frost date — see the calendar above for exact timing.

What planting zone is Cass County, MN?

Cass County, Minnesota is in USDA Hardiness Zone 4a. The average last spring frost is May 12 and first fall frost is September 28.

When should I plant Salvia in Cass County, MN?

In Cass County, MN, plant Salvia after the last frost (around May 12) and before the first frost (around September 28). Best results when soil holds above 50°F.

What growing zone is Cass County, MN for Salvia?

Cass County sits in USDA Zone 4a. Salvia grows reliably in zones 2a through 11b, so it's a good fit here.

Can Salvia grow in Cass County's climate?

Yes — Salvia grows well in Cass County's temperate climate. Cass County averages a 139-day frost-free season, with last frost around May 12 and first frost around September 28.

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Your Cass County Garden Planner — Free

A 22-page printable planner built for Cass County (Zone 4a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Cass County, MN. Local conditions may vary. Last updated: June 2026.

Sources & credits

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