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When to Plant Echinacea in St. Mary's County, MD

Echinacea (purple coneflower) is a native prairie perennial valued for its immune-supporting properties and beautiful daisy-like flowers that attract pollinators.

St. Mary's County, Maryland is in USDA Zone 7a. The average last spring frost is April 5 and the first fall frost is November 4, giving you a growing season of approximately 213 days.

At an elevation of 156 feet, St. Mary's County receives approximately 41.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 92°F, providing good warmth for Echinacea during the growing season.

St. Mary's County, MD (Zone 7a) Long season
213 days
Last Spring Frost April 5
213 growing days
First Fall Frost November 4

St. Mary's County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Apr 4 🍅 Harvest: Aug 8 – Nov 14
Recommended (50%) ✗ May not fit
Transplant: Apr 12 🍅 Harvest: Aug 16 – Nov 22
Safe Start (90%) ✗ May not fit
Transplant: May 3 🍅 Harvest: Sep 6 – Dec 13

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.8″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Echinacea needs ~2,850 GDD — county provides 4,047 GDD Excellent fit

Echinacea Planting Timeline — St. Mary's County, MD

Echinacea Planting Calendar

Activity When Date Range
Transplant Outdoors April 12 Apr 12 – Apr 26
Harvest August 16 Aug 16 – Nov 22

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April Transplant Outdoors
May
June
July
August Harvest
September Harvest
October Harvest
November Harvest
December

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Low — drought tolerant

Days to Maturity

120–180 days

Soil pH

6 – 7

USDA Zone

Zone 7a

Growing Season

213 days

Growing Tips for St. Mary's County

Start seeds indoors 8-10 weeks before last frost or direct sow in fall for spring germination. Seeds need cold stratification. Deadhead to prolong blooming or leave seed heads for birds.

Companion Planting

Good Companions

Level Up Your Garden

Frequently Asked Questions

When should I plant Echinacea in St. Mary's County, MD?

St. Mary's County is in Zone 7a with an average last frost of April 5. Plan your Echinacea planting based on this frost date — see the calendar above for exact timing.

What planting zone is St. Mary's County, MD?

St. Mary's County, Maryland is in USDA Hardiness Zone 7a. The average last spring frost is April 5 and first fall frost is November 4.

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Plan Your Garden with Confidence

Get our free Garden Planner — designed to help St. Mary's County gardeners in Zone 7a organize planting dates, track what's growing, and never miss a planting window.

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Free download. Plan your entire garden season in minutes.

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