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When to plant Blackberries in Warren County, IL

In Warren County, Blackberries is a single-season spring crop — there's no second fall window. Plant May 4–May 18 for an 365–730-day harvest, finishing well before the October 21 first frost.

When to Plant Blackberries in Warren County, IL

Blackberries

Blackberries are vigorous bramble fruits that produce sweet-tart berries on thorny or thornless canes. They are prolific producers and relatively low-maintenance once established.

Warren County, Illinois is in USDA Zone 5b. The average last spring frost is April 13 and the first fall frost is October 21, giving you a growing season of approximately 191 days.

At an elevation of 801 feet, Warren County receives approximately 36.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Blackberries during the growing season.

Warren County, IL (Zone 5b) Moderate season
191 days
Last Spring Frost April 13
191 growing days
First Fall Frost October 21

Warren County Soil Profile

Soil Type

Silt Loam

Soil pH

6.0-7.0

Drainage

Well Drained

Blackberries Planting Timeline — Warren County, IL

Blackberries Planting Calendar

Activity When Date Range
Transplant Outdoors May 4 May 4 – May 18

· 24" apart · Rows 72" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

365–730 days

🧪 Soil pH

Needs 5.5–7 · Your soil: N/A

🗺️ USDA Zone

Zone 5b

📆 Growing Season

191 days in Warren County

Growing Tips for Warren County

Plant bare-root canes in spring. Provide a sturdy trellis system. Prune out spent fruiting canes after harvest. New canes fruit in their second year (floricanes).

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Peppers

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Blackberries in Warren County, IL?

Warren County is in Zone 5b with an average last frost of April 13. Plan your Blackberries planting based on this frost date — see the calendar above for exact timing.

What planting zone is Warren County, IL?

Warren County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 13 and first fall frost is October 21.

When should I plant Blackberries in Warren County, IL?

In Warren County, IL, plant Blackberries after the last frost (around April 13) and before the first frost (around October 21). Best results when soil holds above 50°F.

What growing zone is Warren County, IL for Blackberries?

Warren County sits in USDA Zone 5b. Blackberries grows reliably in zones 5a through 10b, so it's a good fit here.

Can Blackberries grow in Warren County's climate?

Yes — Blackberries grows well in Warren County's temperate climate. Warren County averages a 191-day frost-free season, with last frost around April 13 and first frost around October 21.

🌱

Your Warren County Garden Planner — Free

A 22-page printable planner built for Warren County (Zone 5b). 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 Warren County, IL. Local conditions may vary. Last updated: June 2026.

Sources & credits

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