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When to Plant Hyssop in Parker County, TX

Parker County, Texas Zone 8a May

What to do in May

Here's what deserves your attention in Parker County, Texas this month. Everything below is tailored to Zone 8a and timed around your local frost dates.

Avg. last frost March 18
Avg. first frost November 12
Soil temp (4") 57°F
Watering Low
Pest pressure Moderate
Daylight 13.7 hrs
Coming up in June — start thinking about
  • 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.

Parker County, Texas is in USDA Zone 8a. The average last spring frost is March 18 and the first fall frost is November 12, giving you a growing season of approximately 239 days.

At an elevation of 4,469 feet, Parker County receives approximately 60.6 inches of rainfall annually with predominantly clay soil. Summer highs average 89°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.

Parker County, TX (Zone 8a) Long season
239 days
Last Spring Frost March 18
239 growing days
First Fall Frost November 12
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Parker County Soil Profile

Soil Type

Clay

Soil pH

7.1-8.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (107 days to spare)
Transplant: Mar 13 🍅 Harvest: May 22 – Jul 24
Recommended (50%) ✓ Fits season (99 days to spare)
Transplant: Mar 25 🍅 Harvest: Jun 3 – Aug 5
Safe Start (90%) ✓ Fits season (96 days to spare)
Transplant: Apr 19 🍅 Harvest: Jun 28 – Aug 30

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 Parker County

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

Soil pH

Your soil pH (7.1–8.4) overlaps with Hyssop's range (6.0–8.0), though not a perfect match.

Soil Texture

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

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 239-day season

Sow every 8 weeks. Last sowing by Aug 14 to harvest before frost.

Plant Water Budget

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

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 1.6" 0" ❄️ Dormant
Feb 1.9" 0" ❄️ Dormant
Mar 2.2" 3.5" 0" ✅ Rainfall sufficient
Apr 2.2" 5.7" 0" ✅ Rainfall sufficient
May 2.2" 9.5" 0" ✅ Rainfall sufficient
Jun 2.2" 9.5" 0" ✅ Rainfall sufficient
Jul 2.2" 8" 0" ✅ Rainfall sufficient
Aug 2.2" 7.3" 0" ✅ Rainfall sufficient
Sep 2.2" 5.8" 0" ✅ Rainfall sufficient
Oct 2.2" 3.8" 0" ✅ Rainfall sufficient
Nov 2.2" 2.3" 0" ✅ Rainfall sufficient
Dec 1.6" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Parker 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 ~1,340 GDD — county provides 4,003 GDD Excellent fit

Hyssop Planting Timeline — Parker County, TX

Hyssop Planting Calendar

Activity When Date Range
Transplant Outdoors March 25 Mar 25 – Apr 8
Harvest June 3 Jun 3 – Aug 5

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

Month-by-Month Timeline

MonthActivities
January
February
March Transplant Outdoors
April Transplant Outdoors
May
June Harvest
July Harvest
August Harvest
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: acceptable

🗺️ USDA Zone

Zone 8a

📆 Growing Season

239 days in Parker County

Growing Tips for Hyssop in Parker County

Direct sow Hyssop outdoors after March 18 in Parker County when soil has warmed and frost danger has passed.

With Parker County's clay soil (38% 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 Parker County, TX?

Parker County is in Zone 8a with an average last frost of March 18. Plan your Hyssop planting based on this frost date — see the calendar above for exact timing.

What planting zone is Parker County, TX?

Parker County, Texas is in USDA Hardiness Zone 8a. The average last spring frost is March 18 and first fall frost is November 12.

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Your Parker County Garden Planner — Free

A 24-page printable planner built for Parker County (Zone 8a). 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 Parker 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.