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When to Plant Lemon Verbena in Harris County, TX

Harris County, Texas Zone 9b May

Your May planting checklist for Harris County, Texas

A quick May briefing for Harris County, Texas gardeners — what's urgent, what's next, and what can wait.

Avg. last frost February 14
Avg. first frost December 4
Soil temp (4") 77°F
Watering Low
Pest pressure High
Daylight 13.5 hrs
  1. It's harvest week for lemon verbena

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

Get ahead of June
  • 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.

Harris County, Texas is in USDA Zone 9b. The average last spring frost is February 14 and the first fall frost is December 4, giving you a growing season of approximately 293 days.

At an elevation of 390 feet, Harris County receives approximately 67.7 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 102°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. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Lemon Verbena root diseases.

Harris County, TX (Zone 9b) Year-round
293 days
Last Spring Frost February 14
293 growing days
First Fall Frost December 4

Harris County Soil Profile

Soil Type

Sandy Loam

Soil pH

5.3-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (153 days to spare)
Start indoors: Dec 26 Transplant: Feb 13 🍅 Harvest: Apr 17 – Jun 26
Recommended (50%) ✓ Fits season (153 days to spare)
Start indoors: Jan 3 Transplant: Feb 21 🍅 Harvest: Apr 25 – Jul 4
Safe Start (90%) ✓ Fits season (149 days to spare)
Start indoors: Jan 25 Transplant: Mar 15 🍅 Harvest: May 17 – Jul 26

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 Harris County

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

Soil pH

Your soil pH (5.3–6.5) is more acidic than Lemon Verbena prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.2%). Annual compost additions will help Lemon Verbena.

How to Plant Lemon Verbena

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

Succession Planting Lemon Verbena

5
successive plantings in your 293-day season

Sow every 6.9 weeks. Last sowing by Sep 05 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 86 gal / 100 sq ft

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 1.6" 0" ❄️ Dormant
Feb 4.3" 2.7" 1.6" 💧 Light watering
Mar 4.3" 3.8" 0.5" 💧 Light watering
Apr 4.3" 7.4" 0" ✅ Rainfall sufficient
May 4.3" 10.1" 0" ✅ Rainfall sufficient
Jun 4.3" 10" 0" ✅ Rainfall sufficient
Jul 4.3" 9.6" 0" ✅ Rainfall sufficient
Aug 4.3" 8.5" 0" ✅ Rainfall sufficient
Sep 4.3" 6.3" 0" ✅ Rainfall sufficient
Oct 4.3" 3.9" 0.4" 💧 Light watering
Nov 4.3" 2.2" 2.1" 💧 Light watering
Dec 4.3" 1.6" 2.7" 🚿 Regular watering

Water needs are for active growing months only (Feb–Dec in Harris 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 ~1,988 GDD — county provides 7,791 GDD Excellent fit

Lemon Verbena Planting Timeline — Harris County, TX

Lemon Verbena Planting Calendar

Activity When Date Range
Start Indoors January 3 Jan 3 – Jan 17
Transplant Outdoors February 21 Feb 21 – Mar 7
Direct Sow February 21 Feb 21 – Mar 14
Harvest April 25 Apr 25 – Jul 4

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 9b

📆 Growing Season

293 days in Harris County

Growing Tips for Lemon Verbena in Harris County

Direct sow Lemon Verbena outdoors after February 14 in Harris County when soil has warmed and frost danger has passed.

Sandy soil in Harris 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 102°F in Harris County, provide afternoon shade for Lemon Verbena and water deeply in the morning.

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 Harris County, TX?

Harris County is in Zone 9b with an average last frost of February 14. Plan your Lemon Verbena planting based on this frost date — see the calendar above for exact timing.

What planting zone is Harris County, TX?

Harris County, Texas is in USDA Hardiness Zone 9b. The average last spring frost is February 14 and first fall frost is December 4.

🌱

Your Harris County Garden Planner — Free

A 24-page printable planner built for Harris 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 Harris County, TX. 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.