Blog

When to Plant Horehound in Rockwall County, TX

Rockwall County, Texas Zone 8b May

What to do in May

Your Rockwall County, Texas garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost March 9
Avg. first frost November 20
Soil temp (4") 75°F
Watering Low
Pest pressure High
Daylight 13.7 hrs
June prep starts now
  • First harvests: horehound

Instant PDF download. No spam, unsubscribe any time.

Horehound is a woolly, drought-tolerant perennial herb traditionally used for cough remedies and candy. It has a distinctive bitter, menthol-like flavor.

Rockwall County, Texas is in USDA Zone 8b. The average last spring frost is March 9 and the first fall frost is November 20, giving you a growing season of approximately 256 days.

At an elevation of 74 feet, Rockwall County receives approximately 71.3 inches of rainfall annually with predominantly clay soil. Summer highs average 91°F, providing good warmth for Horehound during the growing season. Clay soil retains moisture well for Horehound, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Horehound root diseases.

Rockwall County, TX (Zone 8b) Long season
256 days
Last Spring Frost March 9
256 growing days
First Fall Frost November 20

Rockwall County Soil Profile

Soil Type

Clay

Soil pH

7.2-8.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (114 days to spare)
Transplant: Mar 8 🍅 Harvest: May 24 – Jul 19
Recommended (50%) ✓ Fits season (116 days to spare)
Transplant: Mar 16 🍅 Harvest: Jun 1 – Jul 27
Safe Start (90%) ✓ Fits season (98 days to spare)
Transplant: Apr 17 🍅 Harvest: Jul 3 – Aug 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 Rockwall County

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

Soil pH

Your soil pH (7.2–8.1) overlaps with Horehound's range (6.0–8.0), though not a perfect match.

Soil Texture

Heavy clay soil (46% clay) in Rockwall County compacts easily and drains slowly. Amend with compost and avoid working soil when wet.

Organic Matter

Organic matter is moderate (2.7%). Annual compost additions will help Horehound.

How to Plant Horehound

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

Succession Planting Horehound

4
successive plantings in your 256-day season

Sow every 8.6 weeks. Last sowing by Aug 22 to harvest before frost.

Plant Water Budget

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

Monthly Watering Guide for Horehound

Horehound 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 Horehound Needs Rainfall You Supplement Action
Jan 2" 0" ❄️ Dormant
Feb 2.7" 0" ❄️ Dormant
Mar 2.2" 4.5" 0" ✅ Rainfall sufficient
Apr 2.2" 6.7" 0" ✅ Rainfall sufficient
May 2.2" 12.1" 0" ✅ Rainfall sufficient
Jun 2.2" 10" 0" ✅ Rainfall sufficient
Jul 2.2" 9.6" 0" ✅ Rainfall sufficient
Aug 2.2" 9" 0" ✅ Rainfall sufficient
Sep 2.2" 6.7" 0" ✅ Rainfall sufficient
Oct 2.2" 4.1" 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 Rockwall County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Horehound 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.

Horehound needs ~1,506 GDD — county provides 4,672 GDD Excellent fit

Horehound Planting Timeline — Rockwall County, TX

Horehound Planting Calendar

Activity When Date Range
Transplant Outdoors March 16 Mar 16 – Mar 30
Harvest June 1 Jun 1 – Jul 27

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

75–90 days

🧪 Soil pH

Needs 6–8 · Your soil: acceptable

🗺️ USDA Zone

Zone 8b

📆 Growing Season

256 days in Rockwall County

Growing Tips for Horehound in Rockwall County

Direct sow Horehound outdoors after March 09 in Rockwall County when soil has warmed and frost danger has passed.

With Rockwall County's clay soil (46% clay), work in 3-4 inches of compost before planting Horehound. Avoid tilling when soil is wet to prevent compaction.

General growing tips

Direct sow or start from divisions. Thrives in poor, dry soil. Harvest stems just before flowering. Deadhead to prevent aggressive self-seeding. Very drought-tolerant once established.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Horehound in Rockwall County, TX?

Rockwall County is in Zone 8b with an average last frost of March 9. Plan your Horehound planting based on this frost date — see the calendar above for exact timing.

What planting zone is Rockwall County, TX?

Rockwall County, Texas is in USDA Hardiness Zone 8b. The average last spring frost is March 9 and first fall frost is November 20.

🌱

Your Rockwall County Garden Planner — Free

A 24-page printable planner built for Rockwall 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.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Rockwall 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.