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When to Plant Lemon Verbena in Graham County, AZ

Graham County, Arizona Zone 8b May

May to-do list for Graham County, Arizona

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

Avg. last frost April 6
Avg. first frost November 5
Soil temp (4") 62°F
Watering Critical
Pest pressure Moderate
Daylight 13.7 hrs
  1. Start lemon verbena under lights

    Your window is short. These crops want several weeks of indoor growth before they go outside.

To set up a strong June, finish these tasks
  • First harvests: lemon verbena

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Lemon verbena is a deciduous shrub with intensely lemon-scented leaves that retain their aroma when dried. It makes an exceptional tea and adds citrus flavor to dishes.

Graham County, Arizona is in USDA Zone 8b. The average last spring frost is April 6 and the first fall frost is November 5, giving you a growing season of approximately 213 days.

At an elevation of 2,604 feet, Graham County receives approximately 8 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 98°F, so Lemon Verbena may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Lemon Verbena will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Lemon Verbena successfully. Mulch heavily to conserve soil moisture.

Graham County, AZ (Zone 8b) Long season
213 days
Last Spring Frost April 6
213 growing days
First Fall Frost November 5

Graham County Soil Profile

Soil Type

Sandy Loam

Soil pH

7-8.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (81 days to spare)
Start indoors: Jan 24 Transplant: Mar 28 🍅 Harvest: May 30 – Aug 8
Recommended (50%) ✓ Fits season (66 days to spare)
Start indoors: Feb 16 Transplant: Apr 20 🍅 Harvest: Jun 22 – Aug 31
Safe Start (90%) ✓ Fits season (70 days to spare)
Start indoors: Mar 12 Transplant: May 14 🍅 Harvest: Jul 16 – Sep 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 Graham County

How your county's soil matches Lemon Verbena's growing requirements.

Soil pH

Your soil pH (7.0–8.8) is more alkaline than Lemon Verbena prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Lemon Verbena.

Organic Matter

Organic matter is low (0.8%). Add 2-3 inches of compost before planting Lemon Verbena.

How to Plant Lemon Verbena

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Succession Planting Lemon Verbena

4
successive plantings in your 213-day season

Sow every 6.9 weeks. Last sowing by Aug 07 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.2″/week
You supply
1.4″/week
Watering frequency 2-3 times/week
Season total 2,598 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Lemon Verbena

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

Month Lemon Verbena Needs Rainfall You Supplement Action
Jan 0.5" 0" ❄️ Dormant
Feb 0.5" 0" ❄️ Dormant
Mar 0.5" 0" ❄️ Dormant
Apr 4.3" 0.3" 4" 🚿 Regular watering
May 4.3" 0.2" 4.1" 🚿 Regular watering
Jun 4.3" 0.3" 4" 🚿 Regular watering
Jul 4.3" 1.2" 3.1" 🚿 Regular watering
Aug 4.3" 1.8" 2.5" 🚿 Regular watering
Sep 4.3" 1" 3.3" 🚿 Regular watering
Oct 4.3" 0.8" 3.5" 🚿 Regular watering
Nov 4.3" 0.5" 3.8" 🚿 Regular watering
Dec 0.5" 0" ❄️ Dormant

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

Lemon Verbena 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.

Lemon Verbena needs ~1,762 GDD — county provides 5,005 GDD Excellent fit

Lemon Verbena Planting Timeline — Graham County, AZ

Lemon Verbena Planting Calendar

Activity When Date Range
Start Indoors February 16 Feb 16 – Mar 2
Transplant Outdoors April 20 Apr 20 – May 4
Direct Sow April 13 Apr 13 – May 4
Harvest June 22 Jun 22 – Aug 31

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Start Indoors
April Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
June Harvest
July Harvest
August Harvest
September
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 8b

📆 Growing Season

213 days in Graham County

Growing Tips for Lemon Verbena in Graham County

Direct sow Lemon Verbena outdoors after April 06 in Graham County when soil has warmed and frost danger has passed.

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

With summer highs reaching 98°F in Graham County, provide afternoon shade for Lemon Verbena and water deeply in the morning.

Graham County receives only 8" of rain annually. Lemon Verbena needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Grow in a container in cold climates and bring indoors for winter. Prune back hard in spring. Harvest leaves anytime but flavor peaks just before flowering. Dries well for tea.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Lemon Verbena in Graham County, AZ?

Graham County is in Zone 8b with an average last frost of April 6. Plan your Lemon Verbena planting based on this frost date — see the calendar above for exact timing.

What planting zone is Graham County, AZ?

Graham County, Arizona is in USDA Hardiness Zone 8b. The average last spring frost is April 6 and first fall frost is November 5.

🌱

Your Graham County Garden Planner — Free

A 24-page printable planner built for Graham County (Zone 8b). 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 Graham 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.