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When to Plant Hyssop in Fresno County, CA

Fresno County, California Zone 9b May

May in the garden — Fresno County, California

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

Avg. last frost March 2
Avg. first frost November 23
Soil temp (4") 72°F
Watering Critical
Pest pressure High
Daylight 14 hrs
  1. Basket week: hyssop

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  • First harvests: hyssop

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Hyssop is a semi-evergreen perennial herb with intense blue flower spikes that attract bees and butterflies. It has a minty, slightly bitter flavor used in liqueurs and teas.

Fresno County, California is in USDA Zone 9b. The average last spring frost is March 2 and the first fall frost is November 23, giving you a growing season of approximately 266 days.

At an elevation of 2,276 feet, Fresno County receives approximately 14.9 inches of rainfall annually with predominantly loam soil. Summer highs average 100°F, so Hyssop may need afternoon shade and extra watering during peak heat. With low rainfall, drip irrigation is essential for growing Hyssop successfully. Mulch heavily to conserve soil moisture.

Fresno County, CA (Zone 9b) Long season
266 days
Last Spring Frost March 2
266 growing days
First Fall Frost November 23

Fresno County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (127 days to spare)
Transplant: Feb 23 🍅 Harvest: May 4 – Jul 6
Recommended (50%) ✓ Fits season (126 days to spare)
Transplant: Mar 9 🍅 Harvest: May 18 – Jul 20
Safe Start (90%) ✓ Fits season (78 days to spare)
Transplant: May 18 🍅 Harvest: Jul 27 – Sep 28

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 Fresno County

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

Soil pH

Your soil pH (6.5–7.5) is within Hyssop's preferred range (6.0–8.0).

Soil Texture

The loam soil in Fresno County is excellent for Hyssop — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.2%). Annual compost additions will help Hyssop.

How to Plant Hyssop

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

Succession Planting Hyssop

4
successive plantings in your 266-day season

Sow every 8 weeks. Last sowing by Aug 25 to harvest before frost.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.2″/week
You supply
0.3″/week
Watering frequency 1-2 times/week
Season total 752 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Hyssop

Hyssop needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Hyssop Needs Rainfall You Supplement Action
Jan 2.8" 0" ❄️ Dormant
Feb 3.3" 0" ❄️ Dormant
Mar 2.2" 2.3" 0" ✅ Rainfall sufficient
Apr 2.2" 1" 1.2" 🚿 Regular watering
May 2.2" 0.4" 1.8" 🚿 Regular watering
Jun 2.2" 0.1" 2.1" 🚿 Regular watering
Jul 2.2" 0" 2.2" 🚿 Regular watering
Aug 2.2" 0" 2.2" 🚿 Regular watering
Sep 2.2" 0.2" 2" 🚿 Regular watering
Oct 2.2" 0.6" 1.6" 🚿 Regular watering
Nov 2.2" 1.3" 0.9" 💧 Light watering
Dec 2.8" 0" ❄️ Dormant

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

Hyssop 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.

Hyssop needs ~2,000 GDD — county provides 6,650 GDD Excellent fit

Hyssop Planting Timeline — Fresno County, CA

Hyssop Planting Calendar

Activity When Date Range
Transplant Outdoors March 9 Mar 9 – Mar 23
Harvest May 18 May 18 – Jul 20

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · 1-2 times/week

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 6–8 · Your soil: ideal

🗺️ USDA Zone

Zone 9b

📆 Growing Season

266 days in Fresno County

Growing Tips for Hyssop in Fresno County

Direct sow Hyssop outdoors after March 02 in Fresno County when soil has warmed and frost danger has passed.

With summer highs reaching 100°F in Fresno County, provide afternoon shade for Hyssop and water deeply in the morning.

Fresno County receives only 15" of rain annually. Hyssop needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Start seeds indoors or direct sow in spring. Prune back in early spring to encourage bushy growth. Hyssop is drought-tolerant once established and thrives in poor soil.

Companion Planting

Good Companions

Avoid Planting Near

  • Radish

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Hyssop in Fresno County, CA?

Fresno County is in Zone 9b with an average last frost of March 2. Plan your Hyssop planting based on this frost date — see the calendar above for exact timing.

What planting zone is Fresno County, CA?

Fresno County, California is in USDA Hardiness Zone 9b. The average last spring frost is March 2 and first fall frost is November 23.

🌱

Your Fresno County Garden Planner — Free

A 24-page printable planner built for Fresno 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 Fresno County, CA. Local conditions may vary. Last updated: May 2026.

Sources & credits

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