When to Plant Lemon Verbena in Contra Costa County, CA
May in Contra Costa County, California — your action list
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.
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Harvest lemon verbena as they ripen
Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.
Get ahead of June
- First harvests: lemon verbena
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.
Contra Costa County, California is in USDA Zone 9b. The average last spring frost is February 26 and the first fall frost is November 29, giving you a growing season of approximately 276 days.
At an elevation of 88 feet, Contra Costa County receives approximately 19 inches of rainfall annually with predominantly loam soil. Summer highs average 93°F, providing good warmth for Lemon Verbena during the growing season. With low rainfall, drip irrigation is essential for growing Lemon Verbena successfully. Mulch heavily to conserve soil moisture.
Contra Costa County Soil Profile
Soil Type
Loam
Soil pH
6.7-7.8
Drainage
Well Drained
Plant Planting Risk Windows
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 Contra Costa County
How your county's soil matches Lemon Verbena's growing requirements.
Soil pH
Your soil pH (6.7–7.8) is more alkaline than Lemon Verbena prefers (6.0–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Contra Costa County is excellent for Lemon Verbena — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.0%). Annual compost additions will help Lemon Verbena.
How to Plant Lemon Verbena
Succession Planting Lemon Verbena
Sow every 6.9 weeks. Last sowing by Aug 31 to harvest before frost.
Plant Water Budget
Water stress score is 8/10 — 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 | — | 4.1" | 0" | ❄️ Dormant |
| Feb | 4.3" | 4.5" | 0" | ✅ Rainfall sufficient |
| Mar | 4.3" | 3" | 1.3" | 💧 Light watering |
| Apr | 4.3" | 1.5" | 2.8" | 🚿 Regular watering |
| May | 4.3" | 0.6" | 3.7" | 🚿 Regular watering |
| Jun | 4.3" | 0.1" | 4.2" | 🚿 Regular watering |
| Jul | 4.3" | 0" | 4.3" | 🚿 Regular watering |
| Aug | 4.3" | 0" | 4.3" | 🚿 Regular watering |
| Sep | 4.3" | 0.2" | 4.1" | 🚿 Regular watering |
| Oct | 4.3" | 0.7" | 3.6" | 🚿 Regular watering |
| Nov | 4.3" | 1.6" | 2.7" | 🚿 Regular watering |
| Dec | — | 2.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Feb–Nov in Contra Costa 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 Planting Timeline — Contra Costa County, CA
Lemon Verbena Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 15 | Jan 15 – Jan 29 |
| Transplant Outdoors | March 5 | Mar 5 – Mar 19 |
| Direct Sow | March 5 | Mar 5 – Mar 26 |
| Harvest | May 7 | May 7 – Jul 16 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors |
| February | — |
| March | Transplant Outdoors Direct Sow |
| April | — |
| May | Harvest |
| June | Harvest |
| July | Harvest |
| August | — |
| 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 9b
📆 Growing Season
276 days in Contra Costa County
Growing Tips for Lemon Verbena in Contra Costa County
Direct sow Lemon Verbena outdoors after February 26 in Contra Costa County when soil has warmed and frost danger has passed.
Contra Costa County receives only 19" 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 →
Lemon Verbena in Other Locations
Frequently Asked Questions
When should I plant Lemon Verbena in Contra Costa County, CA?
Contra Costa County is in Zone 9b with an average last frost of February 26. Plan your Lemon Verbena planting based on this frost date — see the calendar above for exact timing.
What planting zone is Contra Costa County, CA?
Contra Costa County, California is in USDA Hardiness Zone 9b. The average last spring frost is February 26 and first fall frost is November 29.
Your Contra Costa County Garden Planner — Free
A 24-page printable planner built for Contra Costa 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.