Blog

When to Plant Snapdragon in Johnson County, TX

Johnson County, Texas Zone 8b June

Your June planting checklist for Johnson County, Texas

Your garden in Johnson County, Texas is working on a schedule, even when you're not. Here's where you should be this June.

Avg. last frost March 18
Avg. first frost November 12
Soil temp (4") 79°F
Watering Low
Pest pressure High
Daylight 14.1 hrs
  1. Pick snapdragon

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

Get ahead of July
  • First harvests: snapdragon

Instant PDF download. No spam, unsubscribe any time.

Snapdragons (Antirrhinum majus) are classic cool-season annuals whose upright spikes of dragon-lipped flowers are among spring's most dramatic displays. Tolerating light frosts, they bloom from early spring until summer heat shuts them down — then often revive in fall. In zones 9-11 they are grown as fall-planted winter annuals and may re-seed to naturalize.

Johnson County, Texas is in USDA Zone 8b. 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 2,525 feet, Johnson County receives approximately 62.8 inches of rainfall annually with predominantly clay soil. Summer highs average 92°F, providing good warmth for Snapdragon during the growing season. Clay soil retains moisture well for Snapdragon, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Snapdragon root diseases.

Annual Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting Fragrant
Johnson County, TX (Zone 8b) Long season
239 days
Last Spring Frost March 18
239 growing days
First Fall Frost November 12
Share this guide:

Johnson County Soil Profile

Soil Type

Clay

Soil pH

7-7.8

Drainage

Well Drained

Snapdragon Planting Risk Windows

Early Start (70% safe) ✓ Fits season (72 days to spare)
Start indoors: Dec 26 Transplant: Feb 13 🌸 Bloom: Apr 24 – Aug 28
Recommended (50%) ✓ Fits season (64 days to spare)
Start indoors: Jan 7 Transplant: Feb 25 🌸 Bloom: May 6 – Sep 9
Safe Start (90%) ✓ Fits season (61 days to spare)
Start indoors: Feb 1 Transplant: Mar 22 🌸 Bloom: May 31 – Oct 4

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 Johnson County

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

Soil pH

Your soil pH (7.0–7.8) is more alkaline than Snapdragon prefers (6.2–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

Heavy clay soil (42% clay) in Johnson County compacts easily and drains slowly. Amend with compost and avoid working soil when wet.

Organic Matter

Organic matter is moderate (3.1%). Annual compost additions will help Snapdragon.

How to Plant Snapdragon

9"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Snapdragon

4
successive plantings in your 239-day season

Sow every 8 weeks. Last sowing by Aug 04 to harvest before frost.

For a dedicated fall crop, sow by Sep 03.

Snapdragon Water Budget

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

Monthly Watering Guide for Snapdragon

Snapdragon needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Snapdragon Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 2.2" 0" ❄️ Dormant
Mar 4.3" 4.4" 0" ✅ Rainfall sufficient
Apr 4.3" 7.2" 0" ✅ Rainfall sufficient
May 4.3" 8.1" 0" ✅ Rainfall sufficient
Jun 4.3" 11.5" 0" ✅ Rainfall sufficient
Jul 4.3" 7.5" 0" ✅ Rainfall sufficient
Aug 4.3" 6.9" 0" ✅ Rainfall sufficient
Sep 4.3" 6" 0" ✅ Rainfall sufficient
Oct 4.3" 3.6" 0.7" 💧 Light watering
Nov 4.3" 2.1" 2.2" 🚿 Regular watering
Dec 1.7" 0" ❄️ Dormant

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

Snapdragon 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.

Snapdragon needs ~1,615 GDD — county provides 4,541 GDD Excellent fit

Snapdragon Planting Timeline — Johnson County, TX

Snapdragon Planting Calendar

Activity When Date Range
Start Indoors January 7 Jan 7 – Jan 21
Transplant Outdoors February 25 Feb 25 – Mar 11
Direct Sow February 4 Feb 4 – Feb 25
Bloom May 6 May 6 – Sep 9
Fall Sowing September 3 Sep 3 – Sep 17

· 9" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January Start Indoors
February Transplant Outdoors Direct Sow
March Transplant Outdoors
April
May Bloom
June Bloom
July Bloom
August Bloom
September Fall Sowing Bloom
October
November
December
Share this guide:

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6.2–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 8b

📆 Growing Season

239 days in Johnson County

Growing Tips for Snapdragon in Johnson County

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

With Johnson County's clay soil (42% clay), work in 3-4 inches of compost before planting Snapdragon. Avoid tilling when soil is wet to prevent compaction.

General growing tips

Start indoors 10-12 weeks before last frost; seeds need light to germinate — press into moist medium and do not cover. Transplant after hardening off, even if light frosts remain. Pinch seedlings once to encourage branching. Deadhead to prolong blooming. In zones 8-11, sow in fall for a winter-to-spring show. Tall varieties (24-36") make excellent cut flowers.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Snapdragon in Johnson County, TX?

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

What planting zone is Johnson County, TX?

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

🌱

Your Johnson County Garden Planner — Free

A 22-page printable planner built for Johnson 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 Johnson County, TX. Local conditions may vary. Last updated: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.