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When to Plant Hyssop in Stanislaus County, CA

Stanislaus County, California Zone 9b May

May to-do list for Stanislaus County, California

May is a pivotal month for Stanislaus County, California gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost February 24
Avg. first frost November 28
Soil temp (4") 71°F
Watering Critical
Pest pressure High
Daylight 14 hrs
  1. Pick hyssop

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

Get ahead of June
  • 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.

Stanislaus County, California is in USDA Zone 9b. The average last spring frost is February 24 and the first fall frost is November 28, giving you a growing season of approximately 277 days.

At an elevation of 2,887 feet, Stanislaus County receives approximately 15.2 inches of rainfall annually with predominantly loam soil. Summer highs average 94°F, providing good warmth for Hyssop during the growing season. With low rainfall, drip irrigation is essential for growing Hyssop successfully. Mulch heavily to conserve soil moisture.

Stanislaus County, CA (Zone 9b) Year-round
277 days
Last Spring Frost February 24
277 growing days
First Fall Frost November 28

Stanislaus County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (149 days to spare)
Transplant: Feb 13 🍅 Harvest: Apr 24 – Jun 26
Recommended (50%) ✓ Fits season (137 days to spare)
Transplant: Mar 3 🍅 Harvest: May 12 – Jul 14
Safe Start (90%) ✓ Fits season (102 days to spare)
Transplant: Apr 25 🍅 Harvest: Jul 4 – Sep 5

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 Stanislaus County

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

Soil pH

Your soil pH (6.5–7.7) is within Hyssop's preferred range (6.0–8.0).

Soil Texture

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

Organic Matter

Organic matter is moderate (2.6%). 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 277-day season

Sow every 8 weeks. Last sowing by Aug 30 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 803 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 3.1" 0" ❄️ Dormant
Feb 2.2" 3.5" 0" ✅ Rainfall sufficient
Mar 2.2" 2.1" 0.1" 💧 Light watering
Apr 2.2" 1.3" 0.9" 💧 Light watering
May 2.2" 0.5" 1.7" 🚿 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" 0.7" 1.5" 🚿 Regular watering
Nov 2.2" 1.5" 0.7" 💧 Light watering
Dec 2.2" 0" ❄️ Dormant

Water needs are for active growing months only (Feb–Nov in Stanislaus 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 ~1,640 GDD — county provides 5,699 GDD Excellent fit

Hyssop Planting Timeline — Stanislaus County, CA

Hyssop Planting Calendar

Activity When Date Range
Transplant Outdoors March 3 Mar 3 – Mar 17
Harvest May 12 May 12 – Jul 14

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

277 days in Stanislaus County

Growing Tips for Hyssop in Stanislaus County

Direct sow Hyssop outdoors after February 24 in Stanislaus County when soil has warmed and frost danger has passed.

Stanislaus 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 Stanislaus County, CA?

Stanislaus County is in Zone 9b with an average last frost of February 24. Plan your Hyssop planting based on this frost date — see the calendar above for exact timing.

What planting zone is Stanislaus County, CA?

Stanislaus County, California is in USDA Hardiness Zone 9b. The average last spring frost is February 24 and first fall frost is November 28.

🌱

Your Stanislaus County Garden Planner — Free

A 24-page printable planner built for Stanislaus 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 Stanislaus County, CA. 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.