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When to Plant Blackberries in Phillips County, AR

Phillips County, Arkansas Zone 8a May

Your May planting checklist for Phillips County, Arkansas

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 March 14
Avg. first frost November 12
Soil temp (4") 70°F
Watering Low
Pest pressure Moderate
Daylight 13.8 hrs

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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.

Phillips County, Arkansas is in USDA Zone 8a. The average last spring frost is March 14 and the first fall frost is November 12, giving you a growing season of approximately 243 days.

At an elevation of 678 feet, Phillips County receives approximately 50 inches of rainfall annually with predominantly silt loam soil. Summer highs average 93°F, providing good warmth for Blackberries during the growing season.

Phillips County, AR (Zone 8a) Long season
243 days
Last Spring Frost March 14
243 growing days
First Fall Frost November 12

Phillips County Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: Mar 30
Recommended (50%) ✓ Fits season
Transplant: Apr 4
Safe Start (90%) ✓ Fits season
Transplant: Apr 28

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 Phillips County

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

Soil pH

Your soil pH (5.6–6.7) is within Blackberries's preferred range (5.5–7.0).

Soil Texture

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

Organic Matter

Organic matter is moderate (2.8%). Annual compost additions will help Blackberries.

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
0.2″/week
Watering frequency Only during dry spells
Season total 352 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 4.4" 0" ❄️ Dormant
Feb 4" 0" ❄️ Dormant
Mar 4.3" 5.5" 0" ✅ Rainfall sufficient
Apr 4.3" 3.9" 0.4" 💧 Light watering
May 4.3" 4.4" 0" ✅ Rainfall sufficient
Jun 4.3" 4.4" 0" ✅ Rainfall sufficient
Jul 4.3" 5.2" 0" ✅ Rainfall sufficient
Aug 4.3" 4.3" 0" ✅ Rainfall sufficient
Sep 4.3" 3.2" 1.1" 💧 Light watering
Oct 4.3" 2.9" 1.4" 💧 Light watering
Nov 4.3" 3.6" 0.7" 💧 Light watering
Dec 4.2" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Phillips 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 ~10,813 GDD — county provides 4,799 GDD May not mature

Blackberries Planting Timeline — Phillips County, AR

Blackberries Planting Calendar

Activity When Date Range
Transplant Outdoors April 4 Apr 4 – Apr 18

· 24" apart · Rows 72" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April Transplant Outdoors
May
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 8a

📆 Growing Season

243 days in Phillips County

Growing Tips for Blackberries in Phillips County

Direct sow Blackberries outdoors after March 14 in Phillips County when soil has warmed and frost danger has passed.

Your 243.0-day growing season in Phillips 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 Phillips County, AR?

Phillips County is in Zone 8a with an average last frost of March 14. Plan your Blackberries planting based on this frost date — see the calendar above for exact timing.

What planting zone is Phillips County, AR?

Phillips County, Arkansas is in USDA Hardiness Zone 8a. The average last spring frost is March 14 and first fall frost is November 12.

🌱

Your Phillips County Garden Planner — Free

A 24-page printable planner built for Phillips County (Zone 8a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Phillips County, AR. 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.