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When to Plant Mulberries in Gilliam County, OR

Gilliam County, Oregon Zone 7b May

What to do in May

We've pulled the most time-sensitive tasks for Gilliam County, Oregon this May and put them front and centre. Tackle them in order.

Avg. last frost April 25
Avg. first frost October 15
Soil temp (4") 63°F
Watering High
Pest pressure Low
Daylight 14.7 hrs
  1. Harden off and plant mulberries

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

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Mulberries are fast-growing, long-lived trees that produce abundant sweet-tart berries over an extended harvest period. The berries resemble elongated blackberries.

Gilliam County, Oregon is in USDA Zone 7b. The average last spring frost is April 25 and the first fall frost is October 15, giving you a growing season of approximately 173 days.

At an elevation of 965 feet, Gilliam County receives approximately 22.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Mulberries during the growing season.

Gilliam County, OR (Zone 7b) Moderate season
173 days
Last Spring Frost April 25
173 growing days
First Fall Frost October 15

Gilliam County Soil Profile

Soil Type

Silt Loam

Soil pH

5.3-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: May 6
Recommended (50%) ✓ Fits season
Transplant: May 16
Safe Start (90%) ✓ Fits season
Transplant: Jun 3

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 Gilliam County

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

Soil pH

Your soil pH (5.3–6.7) overlaps with Mulberries's range (5.5–7.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Mulberries.

Organic Matter

Organic matter is excellent (4.5%) — Mulberries will thrive.

How to Plant Mulberries

120"
Between Plants
144"
Between Rows

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
0.8″/week
Watering frequency 2-3 times/week
Season total 1,164 gal / 100 sq ft

Monthly Watering Guide for Mulberries

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

Month Mulberries Needs Rainfall You Supplement Action
Jan 2.8" 0" ❄️ Dormant
Feb 2.8" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 4.3" 1.4" 2.9" 🚿 Regular watering
May 4.3" 1.4" 2.9" 🚿 Regular watering
Jun 4.3" 0.8" 3.5" 🚿 Regular watering
Jul 4.3" 0.3" 4" 🚿 Regular watering
Aug 4.3" 0.5" 3.8" 🚿 Regular watering
Sep 4.3" 0.9" 3.4" 🚿 Regular watering
Oct 4.3" 1.7" 2.6" 🚿 Regular watering
Nov 3.7" 0" ❄️ Dormant
Dec 3.8" 0" ❄️ Dormant

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

Mulberries 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.

Mulberries needs ~17,566 GDD — county provides 2,378 GDD May not mature

Mulberries Planting Timeline — Gilliam County, OR

Mulberries Planting Calendar

Activity When Date Range
Transplant Outdoors May 16 May 16 – May 30

· 120" apart · Rows 144" 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 · 2-3 times/week

📅 Days to Maturity

730–1825 days

🧪 Soil pH

Needs 5.5–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 7b

📆 Growing Season

173 days in Gilliam County

Growing Tips for Mulberries in Gilliam County

Direct sow Mulberries outdoors after April 25 in Gilliam County when soil has warmed and frost danger has passed.

Your 173.0-day growing season in Gilliam County is tight for Mulberries (730.0-1825.0 days to maturity). Start indoors and choose early-maturing varieties.

Gilliam County receives only 22" of rain annually. Mulberries needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Plant away from driveways and patios as fallen berries stain. Minimal pruning is needed. Harvest by shaking branches over a tarp. Birds love mulberries so plant extra.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Mulberries in Gilliam County, OR?

Gilliam County is in Zone 7b with an average last frost of April 25. Plan your Mulberries planting based on this frost date — see the calendar above for exact timing.

What planting zone is Gilliam County, OR?

Gilliam County, Oregon is in USDA Hardiness Zone 7b. The average last spring frost is April 25 and first fall frost is October 15.

🌱

Your Gilliam County Garden Planner — Free

A 24-page printable planner built for Gilliam County (Zone 7b). 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 Gilliam County, OR. 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.