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When to Plant Hyssop in Hill County, TX

Hill County, Texas Zone 8b May

May to-do list for Hill County, Texas

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

Avg. last frost March 12
Avg. first frost November 19
Soil temp (4") 65°F
Watering Low
Pest pressure High
Daylight 13.6 hrs
  1. Basket week: hyssop

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

Looking ahead to 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.

Hill County, Texas is in USDA Zone 8b. The average last spring frost is March 12 and the first fall frost is November 19, giving you a growing season of approximately 252 days.

At an elevation of 2,597 feet, Hill County receives approximately 54.7 inches of rainfall annually with predominantly clay soil. Summer highs average 93°F, providing good warmth for Hyssop during the growing season. Clay soil retains moisture well for Hyssop, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Hyssop root diseases.

Hill County, TX (Zone 8b) Long season
252 days
Last Spring Frost March 12
252 growing days
First Fall Frost November 19
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Hill County Soil Profile

Soil Type

Clay

Soil pH

7.3-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (111 days to spare)
Transplant: Mar 12 🍅 Harvest: May 21 – Jul 23
Recommended (50%) ✓ Fits season (112 days to spare)
Transplant: Mar 19 🍅 Harvest: May 28 – Jul 30
Safe Start (90%) ✓ Fits season (99 days to spare)
Transplant: Apr 14 🍅 Harvest: Jun 23 – Aug 25

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 Hill County

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

Soil pH

Your soil pH (7.3–7.7) is within Hyssop's preferred range (6.0–8.0).

Soil Texture

Your clay soil in Hill County is workable for Hyssop. Add compost annually to improve structure.

Organic Matter

Organic matter is moderate (2.9%). 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 252-day season

Sow every 8 weeks. Last sowing by Aug 21 to harvest before frost.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — 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 1.5" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.2" 3.6" 0" ✅ Rainfall sufficient
Apr 2.2" 5.9" 0" ✅ Rainfall sufficient
May 2.2" 6.7" 0" ✅ Rainfall sufficient
Jun 2.2" 9.7" 0" ✅ Rainfall sufficient
Jul 2.2" 7.3" 0" ✅ Rainfall sufficient
Aug 2.2" 7" 0" ✅ Rainfall sufficient
Sep 2.2" 4.8" 0" ✅ Rainfall sufficient
Oct 2.2" 3.5" 0" ✅ Rainfall sufficient
Nov 2.2" 2" 0.2" 💧 Light watering
Dec 1.4" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Hill 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 ~1,580 GDD — county provides 4,977 GDD Excellent fit

Hyssop Planting Timeline — Hill County, TX

Hyssop Planting Calendar

Activity When Date Range
Transplant Outdoors March 19 Mar 19 – Apr 2
Harvest May 28 May 28 – Jul 30

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 6–8 · Your soil: ideal

🗺️ USDA Zone

Zone 8b

📆 Growing Season

252 days in Hill County

Growing Tips for Hyssop in Hill County

Direct sow Hyssop outdoors after March 12 in Hill County when soil has warmed and frost danger has passed.

With Hill County's clay soil (36% clay), work in 3-4 inches of compost before planting Hyssop. Avoid tilling when soil is wet to prevent compaction.

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 Hill County, TX?

Hill County is in Zone 8b with an average last frost of March 12. Plan your Hyssop planting based on this frost date — see the calendar above for exact timing.

What planting zone is Hill County, TX?

Hill County, Texas is in USDA Hardiness Zone 8b. The average last spring frost is March 12 and first fall frost is November 19.

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Your Hill County Garden Planner — Free

A 24-page printable planner built for Hill 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 Hill 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.