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When to Plant Blackberries in Tazewell County, IL

Tazewell County, Illinois Zone 6a May

Your May gardening checklist

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost April 19
Avg. first frost October 15
Soil temp (4") 60°F
Watering Low
Pest pressure Low
Daylight 14.3 hrs
  1. Get blackberries in the ground

    Pick a cloudy afternoon or evening to plant. Less transplant shock, and your seedlings will barely blink.

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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.

Tazewell County, Illinois is in USDA Zone 6a. The average last spring frost is April 19 and the first fall frost is October 15, giving you a growing season of approximately 179 days.

At an elevation of 1,006 feet, Tazewell County receives approximately 40 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Blackberries during the growing season.

Tazewell County, IL (Zone 6a) Moderate season
179 days
Last Spring Frost April 19
179 growing days
First Fall Frost October 15

Tazewell County Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: May 5
Recommended (50%) ✓ Fits season
Transplant: May 10
Safe Start (90%) ✓ Fits season
Transplant: May 24

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.

Soil Compatibility in Tazewell County

How your county's soil matches Blackberries's growing requirements.

Soil pH

Your soil pH (6.3–6.9) is within Blackberries's preferred range (5.5–7.0).

Soil Texture

The silt loam soil in Tazewell County is excellent for Blackberries — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.0%) — Blackberries will thrive.

How to Plant Blackberries

24"
Between Plants
72"
Between Rows

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 98 gal / 100 sq ft

Monthly Watering Guide for Blackberries

Blackberries needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Blackberries Needs Rainfall You Supplement Action
Jan 1.9" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 2.6" 0" ❄️ Dormant
Apr 4.3" 3.9" 0.4" 💧 Light watering
May 4.3" 5.2" 0" ✅ Rainfall sufficient
Jun 4.3" 5.1" 0" ✅ Rainfall sufficient
Jul 4.3" 3.9" 0.4" 💧 Light watering
Aug 4.3" 4.7" 0" ✅ Rainfall sufficient
Sep 4.3" 3.3" 1" 💧 Light watering
Oct 4.3" 3.1" 1.2" 💧 Light watering
Nov 2.6" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Tazewell County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Blackberries Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Blackberries needs ~8,349 GDD — county provides 2,729 GDD May not mature

Blackberries Planting Timeline — Tazewell County, IL

Blackberries Planting Calendar

Activity When Date Range
Transplant Outdoors May 10 May 10 – May 24

· 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

1"/week · Only during dry spells

📅 Days to Maturity

365–730 days

🧪 Soil pH

Needs 5.5–7 · Your soil: ideal

🗺️ USDA Zone

Zone 6a

📆 Growing Season

179 days in Tazewell County

Growing Tips for Blackberries in Tazewell County

Direct sow Blackberries outdoors after April 19 in Tazewell County when soil has warmed and frost danger has passed.

Your 179.0-day growing season in Tazewell County is tight for Blackberries (365.0-730.0 days to maturity). Start indoors and choose early-maturing varieties.

General growing tips

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 Tazewell County, IL?

Tazewell County is in Zone 6a with an average last frost of April 19. Plan your Blackberries planting based on this frost date — see the calendar above for exact timing.

What planting zone is Tazewell County, IL?

Tazewell County, Illinois is in USDA Hardiness Zone 6a. The average last spring frost is April 19 and first fall frost is October 15.

🌱

Your Tazewell County Garden Planner — Free

A 24-page printable planner built for Tazewell County (Zone 6a). 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 Tazewell County, IL. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.