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When to Plant Mulberries in Maricopa County, AZ

Maricopa County, Arizona Zone 9b May

Maricopa County, Arizona gardeners: here's your May plan

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

Avg. last frost January 31
Avg. first frost December 6
Soil temp (4") 66°F
Watering Critical
Pest pressure High
Daylight 13.7 hrs

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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.

Maricopa County, Arizona is in USDA Zone 9b. The average last spring frost is January 31 and the first fall frost is December 6, giving you a growing season of approximately 309 days.

At an elevation of 4,014 feet, Maricopa County receives approximately 12.5 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 108°F, so Mulberries may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Mulberries will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Mulberries successfully. Mulch heavily to conserve soil moisture.

Maricopa County, AZ (Zone 9b) Year-round
309 days
Last Spring Frost January 31
309 growing days
First Fall Frost December 6

Maricopa County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.2-8.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: Jan 31
Recommended (50%) ✓ Fits season
Transplant: Feb 14
Safe Start (90%) ✓ Fits season
Transplant: Mar 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.

Soil Compatibility in Maricopa County

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

Soil pH

Your soil pH (7.2–8.5) is more alkaline than Mulberries prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

Sandy soil in Maricopa County warms quickly in spring but drains fast. Mulberries will need more frequent watering and regular compost additions to retain nutrients.

Organic Matter

Organic matter is low (0.7%). Add 2-3 inches of compost before planting Mulberries.

How to Plant Mulberries

120"
Between Plants
144"
Between Rows

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.2″/week
You supply
1.0″/week
Watering frequency 2-3 times/week
Season total 2,750 gal / 100 sq ft
Drought risk

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

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 4.3" 0.9" 3.4" 🚿 Regular watering
Feb 4.3" 0.8" 3.5" 🚿 Regular watering
Mar 4.3" 0.7" 3.6" 🚿 Regular watering
Apr 4.3" 0.5" 3.8" 🚿 Regular watering
May 4.3" 0.3" 4" 🚿 Regular watering
Jun 4.3" 0.4" 3.9" 🚿 Regular watering
Jul 4.3" 2.1" 2.2" 🚿 Regular watering
Aug 4.3" 2.3" 2" 💧 Light watering
Sep 4.3" 1.9" 2.4" 🚿 Regular watering
Oct 4.3" 1.2" 3.1" 🚿 Regular watering
Nov 4.3" 0.6" 3.7" 🚿 Regular watering
Dec 4.3" 0.8" 3.5" 🚿 Regular watering

Water needs are for active growing months only (Jan–Dec in Maricopa 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 ~39,602 GDD — county provides 9,610 GDD May not mature

Mulberries Planting Timeline — Maricopa County, AZ

Mulberries Planting Calendar

Activity When Date Range
Transplant Outdoors February 14 Feb 14 – Feb 28

· 120" apart · Rows 144" apart

Month-by-Month Timeline

MonthActivities
January
February Transplant Outdoors
March
April
May
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: too_alkaline

🗺️ USDA Zone

Zone 9b

📆 Growing Season

309 days in Maricopa County

Growing Tips for Mulberries in Maricopa County

Direct sow Mulberries outdoors after January 31 in Maricopa County when soil has warmed and frost danger has passed.

Sandy soil in Maricopa County dries quickly — mulch Mulberries with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 108°F in Maricopa County, provide afternoon shade for Mulberries and water deeply in the morning.

Your 310.0-day growing season in Maricopa County is tight for Mulberries (730.0-1825.0 days to maturity). Start indoors and choose early-maturing varieties.

Maricopa County receives only 12" 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 Maricopa County, AZ?

Maricopa County is in Zone 9b with an average last frost of January 31. Plan your Mulberries planting based on this frost date — see the calendar above for exact timing.

What planting zone is Maricopa County, AZ?

Maricopa County, Arizona is in USDA Hardiness Zone 9b. The average last spring frost is January 31 and first fall frost is December 6.

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Your Maricopa County Garden Planner — Free

A 24-page printable planner built for Maricopa County (Zone 9b). 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 Maricopa County, AZ. 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.